The Conversation

The program can work well for polygamous species such as gorillas. Mary Ann McDonald/shutterstock.com

A quick look at the popularity of online dating services like OkCupid and eHarmony shows us that people are pretty comfortable with letting an algorithm choose them a mate. Now we at the Flinders Molecular Ecology Lab want to do a similar thing for other animals.

With human-driven extinctions on the rise, many species are likely to be left relying on captive breeding for their survival. We hope that our algorithm will help ensure these breeding programs are successful, by pairing up matches who will have healthy, thriving offspring.

Unlike human dating services, we cannot ask a snake, fish or possum to answer questions. But we can look at their DNA. This allows us to breed individuals who are not closely related, avoiding the genetic problems that arise from inbreeding, and thus producing healthy populations with a diverse gene pool.

We have created Swinger, a computer program that uses DNA profiling to matchmake endangered animals for captive breeding - especially those that have multiple mates - and which we describe in a paper published in the journal Molecular Ecology Resources. We envision it helping to conserve many endangered animals, with the first animals being native freshwater fishes in Australia.

It’s all in the DNA

Genetic diversity is crucial, because it helps populations to adapt and evolve in response to environmental changes that they may encounter in the future. So maintaining a large gene pool is an important consideration for captive breeding programs, particularly in populations that have already dwindled to small numbers. This makes avoiding inbreeding vitally important.

Many species kept in zoos – such as pandas – have clear family relationships or are bred in pairs and so their parentage is certain. Armed with pedigree information, it is relatively easy for zoos to select unrelated breeding pairs, often by working in collaboration with other zoos.

But most animals in the world are polygamous, with each individual naturally having multiple partners, even around the same time. This is where it becomes harder to track family relationships, unless you can examine their DNA.

It’s easier with pandas - well, the choosing part at least. Ritesh251123/Wikimedia Commons, CC BY-SA

The matchmaking algorithm is also ideal for starting a captive breeding program from individuals newly brought into captivity. This is because we often have no idea about their relationships to each other, except through DNA, and they may be highly related individuals.

The very circumstances that brought about the need for captive breeding also often results in inbreeding in wild populations. This is because the population has reduced in size to the point that individuals may unavoidably breed with their close relatives. This makes it especially important to ensure breeding in captivity occurs between unrelated individuals.

Captive breeding of swingers

Even when dealing with such serious issues as extinction, we like to keep a sense of humour – hence the name Swinger, which we feel is pretty appropriate given that individuals of most species in the world are naturally polygamous. Indeed, our algorithm is just as suitable for setting up polygamous breeding groups as monogamous ones.

The algorithm is inspired by our efforts to save freshwater fishes in Australia. Native freshwater fish lineages recently became at risk of extinction due to human activities during the Millennium Drought in the Murray-Darling Basin, in southeastern Australia. The fish needed to be saved by their removal from the wild before their habitat completely dried out.

We created breeding groups of these rescued polygamous fish. This was done by using DNA information to create, by hand, “swinger” groups of unrelated individuals. The breeding was successful, with offspring reintroduced to the wild. However, the breeding groups were unavoidably sub-optimal because at that time we had no algorithm to work out the best possible mates for individuals.

Swinger is now being used to save native rainbowfish in northern Queensland. Although it is still early days, the rainbowfish breeding has been very successful, producing thousands of fingerlings that our collaborators are releasing to the wild.

We are also using Swinger to inform the design of a breeding program of endangered species of Galápagos giant tortoises previously considered extinct. These tortoises were rediscovered in a remote volcano and moved to the captive breeding facility of the Galápagos National Park. The aim is to reintroduce the captive-born offspring to the island where they evolved.

The brilliance of DNA is that it is in all living things. This means that Swinger could potentially be used to help breed all endangered species with sexual reproduction - especially, of course, the many polygamous species.

To borrow another concept from the world of human dating, there will hopefully soon be “Plenty of Fish” as a result of our efforts.

Catherine R. M. Attard has received funding from the Australian Government and other organisations.

Luciano Beheregaray receives funding from the Australian Research Council.

Jonathan Sandoval Castillo ne travaille pas, ne conseille pas, ne possède pas de parts, ne reçoit pas de fonds d'une organisation qui pourrait tirer profit de cet article, et n'a déclaré aucune autre affiliation que son poste universitaire.

The higher the plume, the bigger the problem. Jim Peaco/Wikimedia Commons

The journal Climatic Change has published a special edition of review papers discussing major natural hazards in Australia. This article is one of a series looking at those threats in detail.

Fire has been a driving force across Australia for millennia. Indeed, the health of many of our ecosystems is intrinsically dependent on fire. But bushfires are also one of our most frequent natural hazards, with a total cost estimated at A$8.5 billion per year.

In the past decade or so, extreme bushfires in southeastern Australia have burned more than a million hectares, claiming more than 200 lives and over 4,000 homes. Similar losses in other major urban areas have prompted questions about whether we are seeing a shift towards a significantly more hazardous fire regime, characterised by increasing fire frequency and intensity, and the development of catastrophic “firestorms”.

While these extreme bushfires account for only a very small percentage of fire events, they are responsible for the lion’s share of bushfire-related losses.

In contrast to typical bushfires, which spread across the landscape as well-defined burning fronts with smoke plumes perhaps a few kilometres high, extreme bushfires exhibit deep and widespread flaming and produce smoke plumes that can extend 10-15km into the atmosphere.

At these altitudes, bushfire plumes can actually develop into thunderstorms (hence the term “firestorm”). As such, extreme bushfires become much more difficult for emergency services to handle, making them all but impossible to suppress and their spread difficult to predict.

Beyond hot, dry and windy

Like other dangerous bushfires, firestorms are driven by hot, dry and windy weather. But to spawn a firestorm, a range of other conditions must also be met; these can include a rugged landscape, particularly nasty weather events that produce “spikes” in fire danger, and conditions in the upper atmosphere that allow fire plumes to grow to considerable heights.

While previous studies have considered past and projected changes in the hot, dry and windy aspect of fire danger, less research has been done on the future projections for these other types of conditions. This means that we have quite a poor understanding of how extreme bushfires might affect us in the future.

As part of a series of reviews produced by the Australian Energy and Water Exchange initiative, my colleagues and I have taken a closer look at the most catastrophic bushfire cases and the factors that drive them, beyond the usual hot, dry and gusty weather.

There has been an overall increase in the frequency of major bushfire events in southeastern Australia since the mid-19th century. In particular, in the past 15 years a major fire event has occurred every 5 years or less. While some of this increase is due to changes in land use since European colonisation, there is also strong evidence of climate-driven changes.

We found that besides increases in dangerous surface fire danger conditions, upper atmospheric conditions have also become more conducive to explosive fire growth. High levels of the c-Haines index, which signals greater potential for a fire’s plume to rise high into the atmosphere, have become considerably more prevalent since the 1980s. The effects of droughts and widespread heatwaves have also contributed to the occurrence of extreme bushfires.

Looking into the future, high c-Haines values are projected to grow more prevalent still, albeit more gradually than over recent decades. Frontal weather patterns associated with particularly bad fire days are also projected to become more frequent during this century, and rainfall is projected to decrease over southwest and southeastern Australia.

All of this suggests that extreme bushfires will become a more common occurrence into the future.

What we still don’t know

Our methods for assessing fire danger do not explicitly account for the effects of extended drought and heatwaves on larger fuel elements such as branches and logs, and so may not properly account for their effects on fire spread and heat release into the atmosphere.

There is also considerable uncertainty about how fuel loads will change into the future. It is possible that the higher fire intensities expected to result from the direct effects of a warmer, drier climate may be offset by lower fuel loads.

Our understanding of extreme fire occurrence is also hampered by the lack of long-term and prehistoric climate data, which makes it hard to work out what the “normal” level of extreme bushfires has been in the past. While charcoal records show promise in this regard, we still don’t know enough about how charcoal is generated, deposited and subsequently preserved during extreme fires.

To predict the future occurrence of extreme bushfires, we also have more work to do in understanding how the trends forecast by global climate models will play out in terms of creating regional-scale fire weather conditions. And we still need to figure out the likely effects of other large-scale patterns such as El Niño.

Given the relatively recent advances that have been made in understanding the key drivers of extreme bushfires, the field is now ready for targeted studies that will help us estimate the future risk of extreme bushfires – and how best we can confront the threat.

Jason Sharples receives funding from the Australian Research Council and the Bushfire and Natural Hazards Cooperative Research Centre.

Australia’s government has announced that it is to ratify the Paris climate agreement, which was struck 11 months ago and entered into force last Friday.

The move comes despite the election of Donald Trump, who has called climate change a Chinese-inspired hoax. Trump has pledged to turn his back on the Paris treaty after he takes office in January, although this would take at least a year and technically leave the Agreement still in force, albeit weakened.

The question for Australia is how Canberra will react to such a seismic shift in US climate policy. The last time a US president pulled the plug on international climate negotiations was in March 2001, when George W. Bush withdrew from the Kyoto treaty. Australia’s prime minister John Howard followed suit on Earth Day 2002.

The temptation for Australia’s current government would be to follow in Trump’s slipstream in much the same way. Despite its 2030 climate target being widely seen as unambitious, Australia still lacks a credible plan to deliver the necessary emissions cuts, and has no renewable energy target beyond 2020.

While Prime Minister Malcolm Turnbull may be a vocal supporter of climate action, not everyone on on his side of politics is as keen – such as MPs Craig Kelly and George Christensen. (It was not always thus under the Liberals.)

The temptation to defect might be strong, but the countervailing pressure will be much stronger that it was in 2002, and the clean energy transition is already underway. Just this week, a high-powered group of business leaders, energy providers, academics and financiers called on Turnbull to expand the renewable energy target and create a market mechanism to phase out coal.

Yet the US election has also reinvigorated Australian opponents of climate action, such as One Nation senators Pauline Hanson and Malcolm Roberts, who were cracking champagne at the prospect of Trump in the White House, and media commentator Andrew Bolt, who jubilantly described Trump’s victory as a “revolt against the left’s arrogance”.

Which bit of history will repeat?

On balance, then, it is still hard to predict Australia’s next move – and past form is little guide for future performance.

Over the past 26 years, Australia has made two largely symbolic commitments to international climate action, and one very concrete refusal.

In 1990, ahead of the 2nd World Climate Conference which fired the starting gun for the United Nations’ climate negotiations, the Hawke government announced a target of a 20% reduction by 2005.

The pledge, however, was laced with crucial caveats, like this one:

…the Government will not proceed with measures which have net adverse economic impacts nationally or on Australia’s trade competitiveness in the absence of similar action by major greenhouse-gas-producing countries.

This target was sidelined in the final United Nations Framework Convention on Climate Change, which Australia signed and ratified in 1992.

In 1997, Australia got a very sweet deal at the Kyoto climate talks, successfully negotiating an 8% increase in greenhouse gases as its emissions “reduction” target, as well as a special loophole that allowed it take account of its large reduction in land clearing since 1990. Australia signed the deal in April 1998, but never ratified it.

Kyoto’s rules hid a multitude of sins, anyway, as Oxford University’s Nicholas Howarth and Andrew Foxall have pointed out:

…its accounting rules obscure the real level of carbon emissions and structural trends at the nation-state level… it has shifted focus away from Australia as the world’s largest coal exporter towards China, its primary customer.

Although Kevin Rudd famously ratified Kyoto and received a standing ovation at the Bali Climate summit in 2007, a stronger Australian emissions reduction target was not forthcoming.

The next big moment came at the Paris negotiations of 2015. Australia’s official pledge was a 26-28% reduction on 2005 levels by 2030 – a target unveiled by the former prime minister Tony Abbott, and which met with a lukewarm response from analysts.

Since then, pressure has been building for Australia to explain how it can meet even that target, given the hostility to renewable energy among the federal government, the lack of a post-2020 renewables target, and the inadequacy of the current Direct Action policy.

And now we are looking at the prospect of a Trump presidency, already described as “a turning point in the history of climate action” and “the end of any serious hope of limiting climate change to 2 degrees”.

In a chaotic world that has confounded pollsters, it seems foolish to bet on anything. But two predictions seem sure: atmospheric concentrations of carbon dioxide will rise, and the future will be … interesting.

Marc Hudson does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

Australia’s iconic Great Barrier Reef has suffered through the worst bleaching event in its history, part of the world’s third mass bleaching event.

However, coral reefs from the other side of the continent have also experienced unprecedented bleaching and coral death. This is bad news because the unique coral reefs of Western Australia’s northwest are home to some of the toughest coral in the world.

Western Australia’s unique coral reefs

Although much less well-known, coral reefs in Western Australia are highly diverse. They include, for example, Australia’s largest fringing reef, the World Heritage-listed Ningaloo Reef, as well as Australia’s largest inshore reef, Montgomery Reef which covers 380 square kilometres.

WA’s remote Kimberley region also features “super-corals” – corals that have adapted to a naturally extreme environment where tidal swings can be up 10m. These corals can therefore tolerate exposure to the air during low tide as well as extreme daily temperature swings.

My past research has shown that these naturally extreme conditions increase the heat tolerance of Kimberley corals but that they are nevertheless not immune to bleaching when water temperatures are unusually hot for too long.

Previously I had put these super-corals in tanks and subjected them to a three-week heatwave to see how they would respond, but I always wondered how they would cope in the wild where such events typically unfold over longer timescales. Unfortunately, I did not have to wait long to find out.

The hottest years on record

2015 was the hottest year on record and 2016 will likely be hotter still. This has caused an unprecedented global coral reef crisis. Although global coral bleaching events already occurred in 1998 and 2010, this third global bleaching event is the longest on record and still ongoing.

Sadly, in WA the Kimberley region was hit the hardest. As part of Australia’s National Coral Bleaching Taskforce, colleagues and I conducted extensive monitoring before, during and after the predicted bleaching event along the entire WA coastline. In the southern Kimberley, we also carried out aerial surveys to assess the situation on a regional level.

The severity and scale of bleaching that we observed in April was devastating. Almost all inshore Kimberley reefs that we surveyed had about 50% bleaching, including Montgomery Reef. Researchers from the Australian Institute of Marine Science found that offshore Kimberley reefs such as Scott Reef fared even worse, with 60-90% bleaching in shallow lagoon waters.

Many corals had already died from the severe bleaching in April, but the final death toll has only been revealed during visits to the Kimberley last month. Vast areas of coral reef are now dead and overgrown with algae, both at the inshore and offshore Kimberley reefs.

According to local Indigenous Rangers and Traditional Owners who assisted in the research, this appears to be unprecedented. Such events had never previously been described in their rich local history of the coastal environment.

Bleached staghorn coral on inshore Kimberley reefs in April 2016. Verena Schoepf Dead staghorn coral on the same reefs in October 2016. Verena Schoepf Some good news

There was nevertheless some good news. Corals living in intertidal areas, where they regularly experience exposure to air, stagnant water, and extreme temperature fluctuations, bleached less than corals from below the low-tide mark, where conditions are far more moderate. And importantly, the majority of intertidal corals were able to fully recover within a few months.

Similarly, researchers from the Western Australian Museum and Curtin University confirmed last month that intertidal coral reefs in the central Kimberley (Bonaparte Archipelago) were in great condition.

Overall, these observations confirm the findings from my past research which showed that highly-variable, extreme temperature environments can boost the bleaching resistance of corals.

It is also important to note that the 2016 severe bleaching event in WA was restricted to the Kimberley region. Ningaloo Reef as well as coral reefs in the Pilbara and the Abrolhos Islands all escaped the bleaching. This is great news because some of these locations are still recovering from major bleaching in 2010-11 and 2013.

Healthy coral at Ningaloo Reef in 2016. Morane Le Nohaic The future of WA’s coral reefs

Although it is now clear that WA’s coral reefs are at risk of bleaching during both El Niño (as in 2016) and La Niña years (as in 2010-11), they have some advantages over other reefs that may hopefully allow them to recover from bleaching more quickly and stay healthy in the long term.

For example, most of WA’s coral reefs are located far away from major population centres and are thus less affected by environmental threats such as poor water quality (though other threats such as oil and gas exploration do exist). We also know that their isolation, particularly in the case of offshore reefs, helped them recover from previous mass bleaching events.

Finally, it is critical that we identify coral populations worldwide that are already naturally adapted to higher temperatures and have a greater bleaching resistance, such as the Kimberley corals.

These super-corals, while not immune to climate change, should be a priority for research into the limits of coral tolerance, as well as conservation efforts.

Verena Schoepf is affiliated with the University of Western Australia, the ARC Centre of Excellence for Coral Reef Studies and the Western Australian Marine Science Institution (WAMSI). The research presented here was funded by WAMSI, the ARC Centre of Excellence for Coral Reef Studies, the PADI Foundation and an ARC Laureate Fellowship to Prof Malcolm McCulloch.

The journal Climatic Change has published a special edition of review papers discussing major natural hazards in Australia. This article part of a series looking at those threats in detail.

Australia is no stranger to heatwaves. Each summer, large areas of the continent fry under intense heat for days on end, causing power outages, public transport delays, and severe impacts to human health. The estimated impact on our workforce alone is US$6.2 billon per year. Heatwaves are also Australia’s deadliest natural hazard, accounting for well over half of all natural disaster-related deaths.

Along with our colleagues, we have taken a close look at what we know and don’t know about heatwaves in Australia, as part of a series of reviews produced by the Australian Energy and Waster Exchange initiative.

Let’s start with the stuff we know. First, we are very clear on the weather systems that drive heatwaves in Australia’s densely populated coastal areas. Typically, a persistent high-pressure system sits next to the region experiencing the heatwave, pushing hot air from the centre of Australia towards that region. The location of the high depends on the region experiencing the heatwave, but there is always one there.

These high-pressure systems are created and sustained by other weather influences farther afield, for instance. We know for instance that heatwaves in Melbourne are coupled with tropical cyclones to the northwest of Australia.

Other, longer-term variables can affect not just individual heatwaves but their patterns, timing and severity too. So heatwaves are likely to be much longer and more frequent during El Niño than La Niña phases over much of northern and eastern Australia. However, this does not influence heatwaves over Australia’s far southeast – here, the most important driver is changes to wind patterns over the Southern Ocean.

We also know that heatwave trends have increased in the observational record, and, unfortunately, that they will continue to do so. By far the strongest trend is in the number of heatwave days experienced each season. Over much of eastern Australia, this trend is as large as two extra days per season, per decade.

Looking into the future, heatwaves are projected to become more frequent, with increases of between 20 and 40 extra days per season in the north and 5-10 extra days in the south likely by the end of this century, under a “business as usual” scenario. The intensity of heatwaves over southern Australia is also increasing faster than the average temperature. This is not good news for our ageing population, our fragile ecosystems and our outdated infrastructure.

The Australian research community has been successful in leading the development of a comprehensive way to measure marine heatwaves. Just like the atmosphere, areas of the ocean can experience prolonged periods of abnormally warm temperatures. These marine heatwaves can be every bit as damaging as atmospheric ones, decimating marine habitats and killing coral.

What we don’t yet know

Perhaps surprisingly, given the amount of research and public attention that heatwaves attract, they still do not have an official definition. The Bureau of Meteorology uses a concept called excess heat factor, which looks at maximum temperatures and ensuing minimum temperatures over a three-day period, incorporating the key characteristic of heatwaves of heat tending to persist overnight. However, we still do not have a universal definition that fits all situations.

We are also unclear on how the physical mechanisms that drive heatwaves will change under ongoing greenhouse warming. Recent research suggests that background warming will predominantly drive future increases in heatwaves, with some heatwave-inducing systems moving further south. But we don’t really know how future changes to patterns such as El Niño will continue to influence our heatwaves.

We also don’t really understand the extent to which the land surface drives Australian heatwaves. European studies have shown that dry conditions leading up to heatwave season, resulting in more parched soils, are a recipe for more intense and longer events, particularly when coupled with a persistent high-pressure system.

For Australia, we know that dry soil contributed to the deadly heatwave that preceded the Black Saturday bushfires in 2009. But more extensive studies are needed to understand this complex relationship over Australian soil (pun intended).

We also need a more comprehensive understanding of marine heatwaves. So far there has been only a handful of studies describing individual events. We still don’t know how much marine heatwaves have increased over recent decades, or how their causes and severity will change in the future. Given how vulnerable we are to marine heatwaves here in Australia, this topic should be a national research priority.

Finally, we need to develop more practical predictions of how heatwaves are likely to affect people in the future. We know how bad the impacts of heatwaves can be, and we know in general terms how heatwaves will change in the future. Yet the vast majority of our projections come from global climate models. Forecasting the exact impacts calls for finer spatial detail, using regional climate models. But these models are far more computationally expensive to run, and more investment into this area is necessary.

There is no doubt that heatwaves have been, and will continue to be, an integral feature of Australia’s climate, and recent research has taught us a lot about them. But there is more work to be done if we want to safeguard Australians properly from their deadly impacts in the future.

Sarah Perkins-Kirkpatrick receives funding from the Australian Research Council.

Christopher J. White receives funding from various Tasmanian State Government research funding programs, Wine Australia and the Bushfire and Natural Hazard CRC.

Replanting trees is one of the better ways to remove carbon from the atmosphere. CIFOR/Flickr, CC BY-NC-ND

This week international leaders are meeting in Marrakech to thrash out how to achieve the Paris climate agreement, which came into force on Friday. The Marrakech meeting is the 22nd Congress of Parties (or COP22) to the United Nation’s climate convention. One of the key goals of the agreement is to limit global warming to well below 2℃, and aim to limit warming to 1.5℃.

With global greenhouse gas emissions still rising, this is a daunting task. Numerous models, including recent research, suggest we will not be able to achieve this without removing large amounts of greenhouse gases from the atmosphere later this century (known as “negative emissions”).

But scientists are becoming increasingly sceptical of the concept, as it may create more problems than it solves, or fail to deliver. Instead, we need to ramp up action before 2020, before even the earliest targets of the Paris Agreement.

Going negative

Some models suggest that up to 1 trillion tonnes of carbon dioxide needs to be removed from the atmosphere to meet the 1.5℃ goal.

This idea is increasingly being called out as a risky and “highly speculative” strategy to limit warming to 1.5℃, as it puts food security and biodiversity at risk, and may not even be possible to deliver. The Convention on Biodiversity has also now weighed in on the issue, declaring that carbon removal techniques are highly uncertain.

A recent report from the Stockholm Environment Institute (SEI), summarised here, argues that the scale of negative emissions assumed by many climate models is improbably high.

The key components of negative emissions are reducing deforestation, planting trees, and an untested technology called “bioenergy with carbon capture and storage” or BECCS. The involves burning plant matter to produce energy, capturing the waste CO₂, and then storing it underground. The result is less CO₂ in the atmosphere.

But there are several problems with these strategies. For one, the scale of land required for the expected level of negative emissions suggests serious social and ecological risks, since land plays a crucial role in food security, livelihoods and biodiversity conversation.

Indeed, the scale of bioenergy supply in many cases is equivalent to the current global harvest of all biomass – for food, feed, and fibre - assuming a doubling of human harvest of biomass by 2050.

The SEI paper argues that the risks and uncertainties associated with negative emissions could lock us into much higher levels of warming than intended, substantially undermining society’s overall mitigation efforts.

Better ways to remove carbon

So does all of this mean the 1.5℃ goal is out of reach? Some may think so.

However, the SEI analysis finds that if emissions were cut sufficiently quickly and ambitiously, we wouldn’t need to rely so much on negative emissions. We could also choose negative emissions methods with lower impacts on biodiversity, resource demands, and livelihoods.

The SEI analysis optimistically suggests that a maximum of 370 billion to 480 billion tonnes of CO₂ could be removed without exceeding biophysical, technological and social constraints. This would be done through protecting forests and allowing degraded forests to regenerate, along with some reforestation.

Even that would be extremely challenging to achieve, but done right, for example through community forestry and agro-ecological farming,, climate mitigation and sustainable development could go together.

In fact, securing land rights of indigenous peoples and local communities who protect and preserve the carbon stocks in forests is one of the most cost-effective forms of climate mitigation we have, with obvious social co-benefits.

Scaling up

The real threat of negative emissions is the potential to delay emissions reduction into the future. Many modelled pathways for 1.5℃ that include substantial negative emissions suggest that emissions do not begin to decline until the late 2020s.

But limiting negative emissions to lower levels would require immediate global mitigation on a scale greatly exceeding that which has so far been pledged by nations under the Paris Agreement.

We cannot wait until 2020 to speed up global action on climate change - less action now will mean more work later.

Key for strengthening pre-2020 action in Marrakech will be a facilitative dialogue on enhancing ambition and support and a high level ministerial meeting on increased ambition of 2020 commitments under the Kyoto Protocol.

Many countries, including Australia, still have completely inadequate targets for 2020, making arguments about whether they are on track to meet them or not moot.

The Moroccan government has dubbed Marrakech the “action COP”. Action here must focus on the urgent need for global emissions to begin declining before 2020, and on the finance needed to deliver it. This includes scaling up the rollout of renewable energy, halting and reversing the loss of the world’s forests, and tackling rich world consumption patterns to ensure equitable mitigation pathways.

Limiting global warming to 1.5℃ is not only possible, it is the only chance of survival for the most vulnerable communities around the world, who are increasingly exposed to rising sea levels, drought and food shortages.

As Erik Solheim, head of the UN Environment Program (UNEP), and Jacqueline McGlade, UNEP’s chief scientist, wrote in a recent report, those most vulnerable “take little comfort from agreements to adopt mitigation measures and finance adaptation in the future. They need action today”.

Kate Dooley receives funding from the Australian government through an Australian Post-graduate Award.

The great grey owl is imperiled by intensive logging of northern-hemisphere forests. Copyright Ondrej Prosicky/Shutterstock.

Life has existed on Earth for roughly 3.7 billion years. During that time we know of five mass extinction events — dramatic episodes when many, if not most, life forms vanished in a geological heartbeat. The most recent of these was the global calamity that claimed the dinosaurs and myriad other species around 66 million years ago.

Growing numbers of scientists have asserted that our planet might soon see a sixth massive extinction — one driven by the escalating impacts of humanity. Others, such as the Swedish economist Bjørn Lomborg, have characterised such claims as ill-informed fearmongering.

We argue emphatically that the jury is in and the debate is over: Earth’s sixth great extinction has arrived.

Collapse of biodiversity

Mass extinctions involve a catastrophic loss of biodiversity, but what many people fail to appreciate is just what “biodiversity” means. A shorthand way of talking about biodiversity is simply to count species. For instance, if a species goes extinct without being replaced, then we are losing biodiversity.

But there’s much more to biodiversity than just species. Within each species there usually are substantial amounts of genetic, demographic, behavioural and geographic variation. Much of this variation involves adaptations to local environmental conditions, increasing the biological fitness of the individual organism and its population.

Natural variation within two species of sea snails. Upper row: Littorina sitkana. Lower row: Littorina obtusata. Copyright David Reid/Ray Society.

And there’s also an enormous amount of biodiversity that involves interactions among different species and their physical environment.

Many plants rely on animals for pollination and seed dispersal. Competing species adapt to one another, as do predators and their prey. Pathogens and their hosts also interact and evolve together, sometimes with remarkable speed, whereas our internal digestive systems host trillions of helpful, benign or malicious microbes.

Hence, ecosystems themselves are a mélange of different species that are continually competing, combating, cooperating, hiding, fooling, cheating, robbing and consuming one another in a mind-boggling variety of ways.

All of this, then, is biodiversity - from genes to ecosystems and everything in between.

The modern extinction spasm Cumulative vertebrate species extinctions since 1500 compared to the ‘background’ rate of species losses. G. Ceballos et al. (2015) Scientific Advances.

No matter how you measure it, a mass extinctions has arrived. A 2015 study that one of us (Ehrlich) coauthored used conservative assumptions to estimate the natural, or background rate of species extinctions for various groups of vertebrates. The study then compared these background rates to the pace of species losses since the beginning of the 20th century.

Even assuming conservatively high background rates, species have been disappearing far faster than before. Since 1900, reptiles are vanishing 24 times faster, birds 34 times faster, mammals and fishes about 55 times faster, and amphibians 100 times faster than they have in the past.

For all vertebrate groups together, the average rate of species loss is 53 times higher than the background rate.

Extinction filters

To make matters worse, these modern extinctions ignore the many human-caused species losses before 1900. It has been estimated, for instance, that Polynesians wiped out around 1,800 species of endemic island birds as they colonised the Pacific over the past two millennia.

And long before then, early human hunter-gatherers drove a blitzkrieg of species extinctions — especially of megafauna such as mastodons, moas, elephant birds and giant ground sloths — as they migrated from Africa to the other continents.

In Australia, for instance, the arrival of humans at least 50,000 years ago was soon followed by the disappearance of massive goannas and pythons, predatory kangaroos, the marsupial “lion”, and the hippo-sized Diprotodon among others.

Changes in climate could have contributed, but humans with their hunting and fires were almost certainly the death knell for many of these species.

As a result of these pre-1900 extinctions, most ecosystems worldwide went through an “extinction filter”: the most vulnerable species vanished, leaving relatively more resilient or less conspicuous species behind.

Giant ground sloths such as this elephant-sized Megatherium vanished soon after humans arrived in the New World. Copyright Catmando.

And it’s the loss of these survivors that we are seeing now. The tally of all species driven to extinction by humans from prehistory to today would be far greater than many people realise.

Vanishing populations

The sixth great extinction is playing out in other ways too, especially in the widespread annihilation of millions (perhaps billions) of animal and plant populations. Just as species can go extinct, so can their individual populations, reducing both the genetic diversity and long-term survival prospects of the species.

For example, the Asian two-horned rhinoceros once ranged widely across Southeast Asia and Indochina. Today it survives only in tiny pockets comprising perhaps 3% of its original geographic range.

Three-quarters of the world’s largest carnivores, including big cats, bears, otters and wolves, are declining in number. Half of these species have lost at least 50% of their former range.

Likewise, except in certain wilderness areas, populations of large, long-lived trees are falling dramatically in abundance.

WWF’s 2016 Living Planet Report summarises long-term trends in over 14,000 populations of more than 3,700 vertebrate species. Its conclusion: in just the last four decades, the population sizes of monitored mammals, birds, fish, amphibians and reptiles have shrunk by an average of 58% worldwide.

And as populations of many species collapse, their crucial ecological functions decline with them, potentially creating ripple effects that can alter entire ecosystems.

Hence, disappearing species can cease to play an ecological role long before they actually go extinct.

Once a widespread and dominating predator, the tiger today is vanishingly rare across most of its former range. Copyright Matt Gibson Paying the extinction debt

Everything we know about conservation biology tells us that species whose populations are in freefall are increasingly vulnerable to extinction.

Extinctions rarely happen instantly, but the conspiracy of declining numbers, population fragmentation, inbreeding and reduced genetic variation can lead to a fatal “extinction vortex”. In this sense, our planet is currently accumulating a large extinction debt that must eventually be paid.

And we’re not just talking about losing cute animals; human civilisation relies on biodiversity for its very existence. The plants, animals and microorganisms with which we share the Earth supply us with vital ecosystem services. These include regulating the climate, supplying clean water, limiting floods, running nutrient cycles essential to agriculture and forestry, controlling serious crop pests and carriers of diseases, and providing beauty, spiritual and recreational benefits.

Are we preaching doom? Far from it. What we’re saying, however, is that life on Earth is ultimately a zero-sum game. Humans cannot keep growing in number and consuming ever more land, water and natural resources and expect all to be well.

Limiting harmful climate change has become a catchphrase for battling such maladies. But solutions to the modern extinction crisis must go well beyond this.

We also have to move urgently to slow human population growth, reduce overconsumption and overhunting, save remaining wilderness areas, expand and better protect our nature reserves, invest in conserving critically endangered species, and vote for leaders who make these issues a priority.

Without decisive action, we are likely to hack off vital limbs of the tree of life that could take millions of years to recover.

The Slow Loris, a primitive primate, is a denizen of intact rainforests in southern Asia. Copyright hkhtt hj

Paul Ehrlich will present a lecture on the current mass extinction, at James Cook University’s Cairns campus on November 10.

Bill Laurance receives funding from the Australian Research Council and other scientific and philanthropic organisations. He is the director of the JCU Centre for Tropical Environmental and Sustainability Science, and founder and director of ALERT--the Alliance of Leading Environmental Researchers & Thinkers.

Paul Ehrlich does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

The Millennium drought had a huge impact on the Murray-Darling river system. suburbanbloke/Flickr/Wikimedia Commons, CC BY-SA

The journal Climatic Change has published a special edition of review papers discussing major natural hazards in Australia. This article is one of a series looking at those threats in detail.

Droughts are a natural feature of the Australian environment. But the Millennium drought (or “Big Dry”), which ran from 1997 to 2010, was a wake-up call even by our parched standards.

The Millennium drought had major social, economic and environmental impacts. It triggered water restrictions in major cities, and prompted severe reductions in irrigation allocations throughout the vast Murray-Darling Basin.

The Millennium drought also highlighted that, compared to the rest of the world, the impacts of drought on Australia’s society and economy are particularly severe. This is mainly because our water storage and supply systems were originally designed by European settlers who failed to plan for the huge variability in Australia’s climate.

Have we learned the lessons?

Are we likely to fare any better when the next Big Dry hits? It’s important to reflect on how much we actually understand drought in Australia, and what we might expect in the future.

Our study, part of the Australian Water and Energy Exchanges Initiative (OzEWEX), had two aims related to this question. The first was to document what is known and unknown about drought in Australia. The second aim was to establish how Australia’s scientists and engineers can best investigate those unknowns.

The fact is that despite their significance, droughts are generally still poorly understood. This makes it hard to come up with practical, effective strategies for dealing with them when they strike.

One reason for this is that unlike natural hazards with more graphic and measurable impacts (such as floods, cyclones, and bushfires), droughts develop gradually over huge areas, and can last for years. Often they go unnoticed until they trigger widespread water or food shortages, or cause significant energy, economic, health or environmental issues.

By the time you know it’s arrived, a drought can already be doing damage. Bidgee/Wikimedia Commons, CC BY-SA

Drought has been described as a “creeping disaster”, because by the time a drought is identified, it is usually already well under way, the costs to fix it are mounting, and the opportunity to take proactive action has already been missed.

This is complicated still further by the uncertainties around defining, monitoring and forecasting drought – including predicting when a drought will finally end. As in the case of other natural hazards (such as drought’s polar opposite, floods), what we need most is accurate and practically useful information on the likelihood, causes and consequences of droughts in particular areas.

This is a very tricky question, not least because we still need to come up with a rigorous way to distinguish between correlation and causation. For example, are increased local temperatures a cause or a consequence of drought?

The complications don’t end there. Because droughts are so much slower and bigger than other natural disasters, they therefore have much more complicated effects on agriculture, industry and society. Bushfires can be devastating, but they also offer ample opportunities to learn lessons for the next time. Droughts, in contrast, give us limited opportunities to learn how best to prepare.

Yet prepare we must. Given Australia’s history of decades-long swings between wet and dry, and the fact that these swings are projected to grow even stronger, drought will be a key concern for Australia for a long time to come.

What to do next

We therefore make several recommendations to help boost our understanding and management of drought.

1). Reconsider the way drought is defined and monitored to remove confusion between drought causes, impacts and risks. Similarly, there is also a need to better distinguish between drought, aridity, and water scarcity due to over-extractions.

The simplest definition of “drought” is a deficit of water compared with normal conditions. But what is normal? How long does the deficit have to persist, and how severe does it need to be, to be considered a drought? What is meant by water: rainfall, snow, ice, streamflow, water in a storage reservoir, groundwater, soil moisture, or all of these?

The answers to these questions depend very much on the local situation in terms of climate and water use, which varies significantly in space and time and is why the simplest definition of drought is insufficient. We need to develop drought definitions that clearly differentiate drought from long-term changes in aridity and water scarcity, and that capture drought start, duration, magnitude and spatial extent. Such definitions should account for the differences between Australia’s climate zones, the wide variety of end-users and applications of drought monitoring information, and the diversity of droughts that have occurred in the past. There needs to be a common understanding of what a drought is and the differences between drought, aridity and human-induced water scarcity.

2). Improve documentation of droughts that took place before weather records began, in roughly 1900. This will improve our understanding of Australia’s long-term “baseline” drought characteristics (that is, how bad can droughts get? how does the worst drought on record compare with the worst that has ever occurred?), and thus provide the fundamental information needed to successfully manage droughts.

This requires compilation of longer-term and more spatially complete drought histories via the merging of palaeoclimate information with instrumental, satellite, and reanalysis data. This will help us better understand instrumental and pre-instrumental drought behaviour, and put the droughts observed in the instrumental record into context. This work will involve looking at ice cores, tree rings, different tree rings, cave deposits, corals, sediments and historical changes to river channels and floodplains.

3). Improve drought forecasting by developing more realistic models of the many factors that cause (or contribute to) drought. This will help us separate out the influences of natural variability and human-induced climate change, which in turn will help us make more accurate long-term projections.

If we can answer these big research questions, we will all be better prepared when the next big dry inevitably arrives.

Anthony Kiem receives funding from the Australian Research Council and the National Climate Change Adaptation Research Facility.

Fiona Johnson receives funding from the Australian Research Council and World Health Organisation.

Seth Westra receives funding from the Australian Research Council and various State Government research funding programs.

This week’s US Presidential election will likely be more important for climate change action than the United Nations (UN) Climate Change Conference which started in Marrakech yesterday. Whichever candidate makes it to the White House, progressive action on climate change in America, and therefore globally, is going to take a hit.

We have already seen stagnation on climate change action in the lead up to the US election. The mudslinging and controversy of the campaign has taken climate change off the front pages. Climate change has had even less visibility in the US election campaign than it did in the Australian election in July.

It was telling that Hillary Clinton, who had talked up climate policy in the primaries when competing against Bernie Sanders, dropped the climate ball as soon as she had the Democratic party’s nomination.

It wasn’t simply that there was no longer any point taking on climate change in order to win more Sanders supporters, but that climate change was so far down the list of ways Clinton could differentiate herself from the Republican candidate Donald Trump that it seemed pointless to insert it into the election campaign at all.

Trump’s worldview projects a complete abnegation of climate change, as shown by his intention to undo America’s commitment to the Paris climate agreement should he get to the White House.

Trump’s negative attitude towards climate change is another example of his belief in conspiracy theories. But his neglect of climate change is not to be found in deploying denier myths, but his abandonment of a policy stance about anything in favour of filling the airwaves with insults more suited to a bar room brawl.

For many Americans, its 240 year old system of democracy is in great danger. Because so many unemployed and dispossessed Americans feel that neither capitalism nor the two great parties can meet their needs, they are rejecting the political elites and the establishment politics that keep the unequal distribution of wealth in check.

Of course, such a system has always been part of American life. It’s just that it is now at breaking point. It is of no consequence that Trump is himself part of the US economic elite. It is enough that he has himself been a “loser” many times over, and that he speaks the reality-TV language of those who want America to be “great again” both at rallies and on social media.

Ironically, America is a greater power now than it has been in the past. But due to the automation of the increased manufacturing output in heavy industries and the reliance on China for consumer goods, unemployment and income inequality have risen to unacceptable levels. It’s now the turn of working class Americans to be the “losers of globalisation”.

This has given rise to a loss of faith in American institutions, and the celebration of Trump as a bad boy who should be able to do whatever he wants to rail against the establishment.

Many analysts have drawn the comparison between Trump’s version of America and fascism — military isolationism, the ridiculing of “others” (including Muslims, Hispanics, women, Chinese and Mexicans), high levels of paranoia (the media is “rigged”, the election is “rigged”), and the fairy tale conviction that one person alone can save America.

But the real danger for the US is in four years from now. If Trump doesn’t win the presidency, a smarter Republican candidate – one who is actually supported by the floor of the Grand Old Party, actually has policies and appeals to the disaffected – will take US politics to a climate inactive isolationist extreme.

However, a moderating force for climate change is the success of the Paris agreement, which is now in full force. The Paris agreement, which replaces the Kyoto framework, has been ratified extremely quickly by UN standards. It now has almost 100 countries signed up – needing only the 55 countries that account for 55% of global emissions.

This is impressive progress given the scale and complexity of the UN’s framework convention on climate change. The momentum of the Paris agreement provides a kind of political guardrail for achieving stronger action on climate change, leaving no country with an excuse not to join in.

The only counter-force that could reverse this momentum would be the rise of populist support for isolationism within the states signed up to the treaty. And a Trumpist America, whether it eventuates this week or in the future, offers an archetypal case.

The journal Climatic Change has published a special edition of review papers discussing major natural hazards in Australia. This article is the first in a series looking at those threats in detail.

Recent floods in New South Wales, South Australia and Victoria have reminded us of the power of our weather and rivers to wreak havoc on homes, business and even, tragically, lives.

As Dorothea Mackellar poetically pointed out, “droughts and flooding rains” have been a feature of Australia throughout history, so maybe we shouldn’t be all that surprised when they happen.

However, we also know that the reported costs of flooding in Australia have been increasing, most likely through a combination of increased reporting, increased exposure through land use change and population growth, and changes to flood magnitude and severity. So it is critical that we understand what might be causing these changes.

This was the question we asked in our review on how flood impacts have changed over time in Australia and how they may change in the future. We found that despite decades of research in these areas, there are still many gaps in what we know.

Copping a soaking

We know that floods depend not just on how much rain falls, but also on how wet the ground is before a heavy rainfall, and how full the rivers are. We also have evidence that the storms that generate heavy rainfall will become more intense in the future, because as the atmosphere warms it can hold more moisture.

This is particularly the case for storms that last just a few hours; in fact we think that these storms are the most likely to show the largest increases. In urban environments this translates to an even greater flood risk, because the concrete and hard surfaces allow this intense rain to run off quickly through storm drains and into creeks and rivers, rather than seeping into the landscape.

In larger catchments and rural areas the story is more complicated than in cities. If the soil is very wet as a result of rain over the previous weeks and months, then when a big storm hits there will be a lot of runoff. In contrast, if the soil is dry then flooding is less likely to be a problem.

Engineers currently use simple models to estimate this relationship between soil wetness and storm rainfall. But our research indicates that these simple models will need to be replaced with longer-term simulations that model all of the previous rainfall leading up to the storm.

Simple models use simple assumptions to translate rainfall risk into flood risk. But if these assumptions are incorrect, our estimates of flood risk (that is, the probability of a given flood magnitude occurring in any particular year) could be wrong. Flood risk is used to guide infrastructure assessment through cost-benefit ratios, so getting it right is important.

One of the reasons that catchment wetness varies is because of climate cycles like El Niño and La Niña. We have some idea how these and similar ocean cycles affect our climate, including the fact that they can cause fluctations in flood risk over decades-long timescales.

The difficulty here is that for most locations we only have 50 to 60 years of recorded river flow data. This makes it hard to separate out the influences of these climate cycles from other trends in flood data, such as the effect of increasing urbanisation.

There has been progressively less monitoring of streamflow in Australia over the past few decades, and this makes it even harder to understand regional changes in flood risk. Governments need to prioritise investment in data collection to allow us to improve our estimates of the risk of flooding and the associated damages now and in the future.

The recent work by the Bureau of Meteorology to develop a comprehensive set of high quality streamflow gauge data is a step in the right direction, but much more investment is needed in these areas.

Finally, we recommend that continued research into the fundamental changes likely from climate change is required. This requires climate models to be run at a range of resolutions to enable all the important climate processes for extreme rainfall to be properly represented.

Recent pressure on CSIRO’s climate modelling capabilities is concerning – the scientific questions are by no means fully answered on these topics. It is great to see the recent funding of the ARC Centre of Excellence on Climate Extremes. The work of these researchers, combined with ongoing efforts across Australia, will be important to provide better assessments on climate changes. This can help engineers and hydrologists continue to provide accurate flood risk estimates.

Fiona Johnson receives funding from the Australian Research Council and World Health Organisation.

Chris White receives funding from various Tasmanian State Government research funding programs, Wine Australia and the Bushfire and Natural Hazard CRC.

Seth Westra receives funding from the Australian Research Council and various State Government research funding programs.

Bushfires have been the most common natural disaster in New South Wales over the past decade, according to our study published today in Nature’s Scientific Reports.

Our study, the first of its kind, looked at disaster declarations in local government areas (LGAs). We found 207 disasters affected the state between 2004 and 2014. Bushfires were the most common, responsible for 108 disaster declarations, followed by storms (55) and floods (44).

By looking at where disasters were declared, we found a “hotspot” in northern New South Wales, which includes some of the state’s most disadvantaged communities.

This suggests that to help communities prepare for disasters, we need to address underlying causes of disadvantage.

There’s nothing natural about a disaster

Disasters are a regular part of life for communities across the globe. So far in 2016, disasters have cost US$71 billion and claimed some 6,000 lives. Globally, the number and cost of disasters is rising.

Australia has a long history of natural disasters, from catastrophic bushfires to flooding rains. Many people are asking whether such disasters are becoming more frequent, and what we can do to better prevent and prepare for them.

Despite the way we talk about them, fires, floods and storms are not inherently natural disasters. Though they may threaten social systems or the environment, they are more accurately classified as natural hazards.

A disaster occurs when a natural hazard overwhelms a social system’s capacity to cope and respond. Instead, disasters require many agencies and a coordinated response. Many factors such as vulnerability, resilience and population density influence a how a community copes with hazards.

Natural disasters are therefore socially constructed, and this is in Australian legislation on how disasters are declared.

What types of disasters are most common in NSW?

Using data on local government areas (LGAs) involved in Natural Disaster Declarations we examined three types of sudden hazards - bushfires, floods and storms. We found that LGAs in New South Wales were involved in disaster declarations on 905 separate occasions.

Across the state, 27 LGAs experienced no disaster declarations. All of these were located within the Greater Metropolitan Region around Sydney. The highest numbers of disasters declared were in Clarence Valley (21), Richmond Valley (16), Narrabri (15) and Nambucca (15).

While bushfires were the most commonly occurring type of disaster event, floods affected the highest number of LGAs. Bushfire and storm disasters were most common in 2012-13, and floods in 2010-11.

By analysing these data we found a cluster or hotspot in the state’s north east. LGAs here were much more frequently involved in disaster declarations than elsewhere.

What’s causing these disasters?

We found clear differences between the number and type of disaster declarations in different years. We wondered if disasters were linked to El Niño (which can lead to hotter, drier weather in Australia) and La Niña (which can lead to cooler, wetter weather).

We did indeed find that bushfires were more common in hot, dry El Niños, and floods and storms in wetter La Niñas. But the relationship wasn’t “statistically significant” - which is how scientists decide how important a statistical finding is.

This suggests that for NSW at least, the strength of El Niño and La Niña is not a good predictor of the number of bushfire, storm or flood disaster declarations that will be made. This might be for two reasons.

First, the declaration of a disaster is based on its socioeconomic and human impacts – not the physical size or intensity of the actual event. And second, we only have a good data set of disaster declarations back to 2004, a very short period of time to look for detailed patterns.

We also compared disaster declarations to the Australian Bureau of Statistics’ Socio-Economic Indexes for Areas data, a dataset that ranks communities on their relative social disadvantage. Research shows that vulnerable, disadvantaged communities are more susceptible to hazards and disasters.

We found that of the most disadvantaged LGAs in NSW, 43% were found in the state’s disaster hotspot.

While we don’t know exactly why so many disadvantaged communities are found in the disaster hotspot, this demonstrates the role that social disadvantage plays in influencing susceptibility to disasters. This builds on other recent studies about inequality and disadvantage in Australia.

The key message for Australia, and the world, is if we do not deal with the root causes of inequality, injustice, disadvantage and poverty, no amount of spending on disaster risk management will stem ever increasing disaster losses.

What can we do?

The overlap of disadvantage and disaster declarations presents a challenge to communities, disaster managers and governments. Increased funding to address social disadvantage in these communities may increase resilience to natural hazards, preventing them from becoming disasters.

Even Sydney, where all of the LGAs with no disasters were found, shouldn’t become complacent. Areas with less experience of hazards have lower awareness of the risks, and respond less effectively as a result. So even though metropolitan areas are typically better off, if a disaster were to occur, the population here would likely be less prepared to cope with the impacts.

Community outreach and education programs may help increase general awareness of the risks and help communities become better prepared. Similarly, more training and deploying emergency services personnel to disasters elsewhere could help gain insight and experiences which can be brought home.

The 2011 Queensland floods demonstrated the need for better education, risk communication and community awareness.

With flood disasters the most widespread across NSW, it would be prudent to focus on educating communities about floods to increase resilience and help them cope. Increasing resources for the State Emergency Service will also allow for more effective planning, mitigation and response strategies to be developed and implemented.

The damage bill from recent flooding across NSW topped A$500 million. The Bureau of Meteorology has predicted an above-average 2016-17 cyclone season. It is an apt time to pause and reflect on what drives people’s understanding of disaster risk and community resilience.

Dale Dominey-Howes receives funding from AusAID, the Australian Research Council, the Global Resilience Partnership and the Australian National Disaster Resilience Program.

Eleanor Bruce receives funding from ACIAR and the Asia Pacific Network for Global Change Research.

Ruby E. Stephens currently works for the NSW Government. The views expressed in this article are solely her own and are not representative of this organisation.

Sarah Perkins-Kirkpatrick receives funding from the Australian Research Council.

Thomas Sewell now works for the NSW Government and is also a volunteer member of the NSW State Emergency Service. The views expressed in this article are solely his own and are not representative of the opinions of either of these organisations.

Generation Y has grown up in a rapidly warming world. According to the US National Climate Data Centre, every month since February 1985 has seen above average global temperatures, compared with the twentieth century. I have no memories of a “normal” month.

2016 is on track to be the hottest year on record, surpassing the previous records set in 2015 and in 2014. These are just a few of the flurry of recent record temperatures, which includes Australia’s hottest day, week, month, season and year.

The question now is what the future will look like. At some point in the decades to come, these record-breaking temperatures will not be rare; they will become normal. But when exactly?

In a new study just released in the Bulletin of the American Meteorological Society, I (together with co-authors Andrew King and Sarah Perkins-Kirkpatrick) find that on the current greenhouse gas emissions trajectory, global temperatures like 2015 will by normal by 2030, and Australia’s record-breaking 2013 summer will likely be an average summer by 2035.

While we still have time to delay some of these changes, others are already locked in - cutting emissions will make no difference - so we must also adapt to a warmer world. This should be a sobering thought as world leaders gather in Marrakech to begin work on achieving the Paris Agreement which came into force last week.

Today’s extremes, tomorrow’s normal

The recent record-breaking temperatures have often been described as the “new normal”. For example, after the new global temperature record was set in 2016, these high temperatures were described as a new normal.

What is a new normal for our climate? The term has been used broadly in the media and in scientific literature to make sense of climate change. Put simply, we should get used to extremes temperatures, because our future will be extreme.

But without a precise definition, a new normal is limited and difficult to understand. If 2015 was a new normal for global temperatures, what does it mean if 2017, 2018, or 2019 are cooler?

In our study we defined the new normal as the point in time when at least half the following 20 years are warmer than 2015’s record breaking global temperatures.

We examined extreme temperatures in a number of state-of-the-art climate models from an international scientific initiative. We also explored how different future greenhouse gas emissions impact temperatures.

We used four different greenhouse gas scenarios, known as Representative Concentration Pathways, or RCPs. These range from a business-as-usual situation (RCP8.5) to a major cut to emissions (RCP2.6).

It is worth emphasising that real-world emissions are tracking above those covered by these hypothetical storylines.

2015’s record temperatures will likely become normal between 2020 and 2030. Future extremes

Our findings were straightforward. 2015’s record-breaking temperatures will be the new normal between 2020 and 2030 according to most of the climate models we analysed. We expect within a decade or so that 2015’s record temperatures will likely be average or cooler than average.

By 2040, 2015’s temperatures were average or cooler than average in 90% of the models. This result was unaffected by reducing greenhouse gas emissions or not - we are already locked in to a significant amount of further warming.

We also looked at the timing of a new normal for different regions. Australia is a canary in the coal mine. While other regions don’t see extreme temperatures become the new normal until later in the century, Australia’s record-breaking 2013 summer temperatures will be normal by 2035 - according to the majority of the models we looked at.

At smaller spatial scales, such as for state-based based temperature extremes, we can likely delay record-breaking temperatures becoming the new normal by committing to significant greenhouse gas cuts. This would clearly reduce the vulnerability of locations to extreme temperatures.

Living in a warmer world

If you like heading to the beach on hot days, warmer Australian summers seem appealing, not alarming.

But Australia’s position as a hot spot of future extremes will have serious consequences. The 2013 summer, dubbed the “angry summer”, was characterised by extreme heatwaves, widespread bushfires and a strain on infrastructure.

Our results suggest that such a summer will be relatively mild within two decades, and the hottest summers will be much more extreme.

My co-authors, Andrew and Sarah, and I all grew up in a world of above-average temperatures, but our future is in a world were our recent record-breaking temperatures will be mild. Our new research shows this is not a world of more pleasantly hot summer days, but instead of increasingly severe temperature extremes.

These significantly hotter summers present a challenge that we must adapt to. How will we protect ourselves from increases in excess heat deaths and increased fire danger, and our ecosystems from enhanced warming?

While we have already locked ourselves into a future where 2015 will rapidly become a new normal for the globe, we can still act now to reduce our vulnerability to future extreme events occurring in our region, both through cutting emissions and preparing for increased heat.

Sophie Lewis receives funding from the Australian Research Council.

Rainforests sustain stunning numbers of insect species, such as this Horny Devil Katydid from Ecuador. Copy Morley Read/Shutterstock.

Scientists have described around 1.5 million species on Earth - but how many are still out there to be discovered? This is one of the most heated debates in biology. Discounting microbes, plausible estimates range from about half a million to more than 50 million species of unknown animals, plants and fungi.

This biodiversity matters because it could be used to fight human diseases, produce new crops, and offer innovations to help solve the world’s problems.

Why is there so much uncertainty in the numbers? The biggest reason, I argue, is that a lot of biodiversity is surprisingly hard to find or identify. This has profound implications for nature conservation and for our understanding of life on Earth.

Hidden biodiversity

We find new species every day but the organisms that we’re now discovering are often more hidden and more difficult to catch than ever before.

Not surprisingly, the first species to be described scientifically were big and obvious. The earliest naturalists to visit Africa, for instance, could hardly fail to discover zebras, giraffes and elephants.

But recent discoveries are different. For instance, lizard species found today are generally smaller and more often nocturnal than other species of lizard. The tiniest of them, a thumbnail-sized chameleon from Madagascar, was discovered just a few years ago.

Three newly discovered species: (a) a snake-like amphibian from India; (b) the world’s tiniest lizard, and © the only lungless frog species. B. Scheffers et al. (2014) Trends in Ecology & Evolution

Other unknown species are notoriously difficult to capture. For example, a biologist friend of mine was visiting his mother-in-law in north Queensland when her cat strolled in with an odd-looking animal in its mouth. He wrestled the cat’s dinner away and found that it was a mammal species never before seen in Australia called the prehensile-tailed rat.

Now known to be quite common in the Wet Tropics, this tree-dwelling rat almost never enters conventional wildlife traps. We can thank my mate’s mother-in-law’s cat for the discovery.

Other poorly explored places where new species wait to be discovered include the deep sea, soils and caves. After spending some 1,100 hours digging holes in the ground, biologists stumbled over the first species of Indian caecilian, a primitive, snake-like burrowing amphibian never before seen on the subcontinent.

On a far-flung beach in Alaska, a dead animal that washed ashore just last year turned out to be a completely new species of whale.

A frog species discovered in Borneo is the only frog in the world that completely lacks lungs. It lives in fast-flowing streams that are so oxygen-rich that it can breathe solely through its skin.

And a newly discovered spider in Morocco has evolved to move and escape predators by somersaulting over sand dunes.

The rainforest rooftop

High on the list of places to discover new species include rainforest canopies. In the early 1980s a Smithsonian Institution ecologist, Terry Erwin, used an insecticidal fog on several trees in the Panamanian rainforest and was stunned by his findings. Most of the insects that fell to the ground were entirely new species. Based on quick calculations he estimated that there could be 30 million species of insects residing in the canopies of the world’s rainforests.

Erwin’s conclusions, as it would be expressed today, went viral. In one fell swoop he had increased estimates of global biodiversity at least tenfold. Most biologists today consider his original estimate too high, however some believe he only overestimated a little.

Rainforest canopies are one of the world’s great biological frontiers. William Laurance Cryptic species

Beyond species that are difficult to find or catch, a lot of unknown biodiversity is staring us right in the face but we simply can’t see it. For these species, new discoveries are down to advances in molecular genetics. Around 60% of all new organisms described today are so-called “cryptic species” that are nearly indistinguishable from one another.

In recent years, for example, we’ve discovered that Africa has not just one species of elephant but two. Formerly considered different subspecies, genetic analyses reveal that they’re as dissimilar to one another as the Asian elephant is to the extinct woolly mammoth.

Genetic studies have also revealed hidden variation among Africa’s giraffes. Just last year, researchers revealed that what was once considered a single species of giraffe is actually four.

And in Costa Rica, one putative species of butterfly turned out to be at least ten.

Genetic studies have revealed that one apparent species of giraffe is actually four. William Laurance

Molecular genetics is turning biology on its head in other ways. Organisms we used to think were only distantly related, such as antelopes, dolphins and whales, are practically cousins in evolutionary terms.

Epicentres of unknown species

One last reason why many species are yet to be discovered is that they only live in a small area of the world. Known as “restricted endemics”, these species are geographically concentrated in certain regions such as tropical mountains, islands, and climatically unusual environments.

Most of Earth’s restricted endemics reside in “biodiversity hotspots”, defined by having more than 1,500 locally endemic plant species and less than 30% of their original habitat remaining. Of 35 currently recognised hotspots, half are in the species-rich tropics with the remainder divided among Mediterranean, islands and other ecosystems.

The world’s 35 recognised biodiversity hotspots. Conservation International

Today, the bulk of new species are being discovered in the biodiversity hotspots. The scary thing is that our recent analyses show that more than half of all hotspots have already lost over 90% of their intact habitat.

Further, most hotspots occur in poorer nations with rapidly-growing populations and escalating social and economic challenges, creating even greater pressures on their already beleaguered ecosystems and species.

Scary implications

Taken collectively, these studies suggest that there’s an enormous wealth of biodiversity on Earth left to discover and that much of it is in danger.

Further, our present knowledge is just scratching the surface. Evolution has had billions of years to create biologically active compounds that can combat human diseases, generate genetic diversity that could save our food crops from disastrous pathogens, and spawn ecological innovations that can inspire marvellous new inventions.

What a tragedy it would be to lose this biodiversity before we have ever had the chance to discover and learn from it.

A new species of Anglerfish discovered this year in the Gulf of Mexico. This bizarre fish has bioluminescent algae in the ‘fishing pole’ above its head to attract prey. Theodore W. Pietsch, University of Washington

Bill Laurance receives funding from the Australian Research Council and other scientific and philanthropic organisations. He is the director of the Centre for Tropical Environmental and Sustainability Science at James Cook University and founder and director of ALERT--the Alliance of Leading Environmental Researchers & Thinkers.

Could allowing environmentally sustainable whaling help end the impasse with Japan? Wanetta Ayers/Wikimedia Commons

Whales had another big win last week – allegedly. The Australian-sponsored resolution adopted by the International Whaling Commission will, in theory, make it harder for nations such as Japan to award themselves special permits for “scientific” whaling.

But as pointed out in The Conversation at the time, the non-binding resolution is likely to have little material effect on whales themselves.

Australia’s delight at the new resolution echoes its response to the International Court of Justice’s 2014 ruling that Japan’s JARPA II whaling program was unlawful.

But since then it has been business as usual for Japan, which simply created a new and different research program – one that makes it very difficult for Australia or anyone else to take it to The Hague again. It is hard to see what these legal and diplomatic victories have achieved in a practical sense, beyond prompting Japan to entrench its resolve to continue with its whaling programs.

It is time for some new tactics. Legal and diplomatic skirmishes with Japan and other pro-whaling nations might feel like the right thing to do. But they deliver little benefit to the whales, and could potentially provoke pro-whaling nations into leaving the IWC altogether.

Longstanding impasse

Before setting out my views as to the way forward, I must state that, on a personal and moral basis, I am absolutely opposed to any whaling whatsoever. I would like to see the complete cessation of whaling by any country in the world.

Unfortunately, however, it does not appear that the events at the recent IWC meeting will change much in practical terms. To be sure, any reform of the IWC is welcome. However, the failure to achieve the required three-quarters majority for the establishment of a South Atlantic whale sanctuary, coupled with the non-binding character of such resolutions, means the IWC has once again proven itself incapable of achieving a strong consensus on contentious issues relating to the protection of whales.

Herein lies the problem. Although this might sound strange coming from a law professor, I believe that the formal legal system is not an effective way to resolve long-entrenched impasses in a way that best serves the interests of the whales themselves.

This is particularly true when the issue draws such emotional responses from all sides. Using the IWC as an ideological battleground does not get us very far in terms of protecting whales.

In its early years, the IWC was characterised as a “whalers’ club”, allocating quotas to member states at levels that significantly harmed whale numbers. Over the past 30-40 years, however, nations such as Australia, New Zealand and Britain have become fiercely anti-whaling, and the commercial whaling industry has met its demise.

As a result, the IWC has over time adopted a much stronger anti-whaling stance, putting it at odds with the whaling states (including Japan, Norway and Iceland) and causing considerable tensions within the IWC.

These tensions have been exacerbated by the fact that, even though the underlying sentiment of many member states has changed, the terms of the 70-year-old treaty have not. That makes it hard for the IWC to morph seamlessly from a resource-management body into a conservation forum.

The logical endpoint

The worst-case outcome would be if Japan (or any other whaling state) feels it is being pushed too far at IWC meetings, and decides to withdraw altogether, which nations can do with as little as six-months’ notice under Article XI of the Convention. Such a country would no longer be bound by any of the restrictions established under the treaty regime – including the moratorium on commercial whaling that has been in effect since the mid-1980s.

Breaking away from the IWC would undoubtedly bring with it significant political and diplomatic costs, making it perhaps unlikely that nations will seriously consider it for now. But if the adversarial tensions continue, pro-whaling states could eventually decide simply to leave the IWC process in order to pursue commercial whaling with little or no international controls. If this were to happen the IWC would have presided over an ecological catastrophe for whales.

Japan’s response to recent developments has shown that a complete cessation of whaling cannot be achieved, at least in the short term. The only rational and pragmatic response is therefore to ensure that as few whales as possible are taken.

I believe the only way for that to happen is for IWC members to agree a compromise based on widely accepted environmental principles such as sustainability. The sad fact for strong anti-whalers such as myself is that this may involve some whaling, albeit on a far more controlled basis than at present.

In this way, the dubious reliance on “scientific” purposes as a disguise for what many observers regard as commercial whaling would end, replaced by a credible system to which everyone has agreed.

It is important not to lose sight of the ultimate purpose here: to preserve whales and do everything possible to protect them. The current emotionally charged legal and diplomatic battles, no matter how worthy and principled, aren’t really in the best interests of these magnificent creatures. An international management regime based on cooperation and clear, objective principles offers a far more promising prospect for their future than the current stalemate.

Steven Freeland does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

The Paris climate agreement comes into legal force today, just 11 months after it was concluded and 30 days after it met its ratification threshold of 55 parties accounting for at least 55% of global greenhouse gas emissions.

By contrast, the Kyoto Protocol, which this treaty now replaces, took more than 8 years to come into force, slowed by the United States’ persistent and erosive opposition.

At the time of writing, the Agreement has been ratified by 94 parties, including the world’s four largest emitters: China, the United States, the European Union and India. As Climate Analytics reports, these nations account for 66% of greenhouse emissions. Even if the United States were to withdraw its support under a Trump presidency, the Paris Agreement will remain in force.

The unprecedented speed with which this has been achieved reflects the acute realisation in the international community – following the debacle of the Copenhagen negotiations in 2009 – that a failure to land this treaty quickly would probably have led to the collapse of the United Nations climate regime.

It also reflects the flexibility of the Agreement itself. Its curious mixture of binding and voluntary elements was designed to be attractive and accommodating, to include both developed and developing states and, specifically, to enable President Barack Obama to sidestep an obstructive US Congress in providing his support.

The result is a legal hybrid that obliges parties to abide by processes, mechanisms and timetables for setting and reviewing their national climate targets, and providing climate finance to developing countries.

But the treaty doesn’t compel those national efforts collectively to meet its core aims: to keep global warming well below 2℃ and as close as possible to 1.5℃ above pre-industrial levels; to peak global emissions as soon as possible; and to reach zero net global emissions in the second half of this century. Worse still, the currently pledged targets would deliver some 3℃ of overall warming by the end of this century.

Because the treaty relies on “intended” national climate targets rather than binding ones, much hinges on the success of the requirement for nations to review and toughen them every five years. The theory is that these global stocktakes of collective progress (beginning with a facilitative dialogue among parties in 2018) will generate enough pressure for individual nations to be encouraged to ratchet up their efforts as they go.

For these reasons – because of its emphasis on process and its lack of compliance mechanisms – the Agreement has been described as a promissory note, or prematurely criticised as inadequate.

A work in progress

Euphoria greeted the successful conclusion of the Paris summit last year, and 175 countries rushed to sign the Agreement when it opened for signatures in April this year (in all, 192 states have now done so). Nevertheless, given the Kyoto experience, few anticipated that this enthusiasm would carry the treaty across the ratification threshold so soon.

So while there will be more celebrations at this year’s UN climate summit, which begins in Marrakech on Monday, negotiators and UN bureaucrats have been caught out. In some senses, the Paris Agreement is a framework agreement within a Framework Agreement (the UN Framework Agreement on Climate Change, of which this is a subsidiary part). It’s a work in progress with lots of details yet to be filled in.

The newly formed Ad Hoc Working Group on the Paris Agreement will be scrambling to define key elements governing the new treaty’s implementation. Many of these elements are critical to the treaty’s long-term effectiveness. They include measures to ensure transparent and effective accounting of countries’ emissions reductions; to work out exactly how the ambition of “zero net emissions” will be met; and to transfer crucial economic measures used under the Kyoto Protocol over to the new framework.

The Agreement requests that this be done by the first session of the Conference of the Parties to the new treaty. As this now will occur in Marrakech, time is too short and such labour is likely to continue through 2017 and perhaps beyond.

From Paris to Australia

Australia is expected to ratify the Agreement later this year. When it does so, it will be committing itself to regularly increasing its efforts to reduce greenhouse gases, improve climate adaptation, and provide climate finance.

Like other nations, Australia will have to review and toughen its climate targets every five years, starting no later than 2020, and report back regularly on its efforts.

While Australia’s 2020 and 2030 emissions targets are seen as weak by international standards, doubts have still been expressed about the federal government’s ability to reach them.

Modelling suggests Australia’s emissions are projected to rise to 21% above 2005 levels by 2030 – rather than fall by the 26-28% proclaimed in its official target.

Australia’s Emissions Reduction Fund has been criticised as being underfunded and focused on the wrong projects. Recent analysis of the contracts awarded through the scheme’s “reverse auctions” confirms that little real additional abatement has been achieved.

Moreover, likely future changes in land use and forestry (mainly reductions in land clearing) will be insufficient to achieve these goals in isolation or to contribute significantly to future ones. The current policy mix means that tougher – and perhaps even existing - national targets could only be met by buying international carbon credits.

In addition, Australia’s reports to the UN will have to reflect “environmental integrity, transparency, accuracy, completeness, comparability and consistency in accordance to rules to be adopted by parties to the Agreement”. The transparency and accountability of Australia’s emissions reporting was recently questioned by the United Nations and by other parties to the Climate Convention. This too will have to improve.

Like other parties, by 2020 Australia will also be invited to provide the UN Climate Secretariat with a long-term low-carbon strategy to run until 2050. Designing an effective transition strategy will require extensive consultation with state and territory governments, industries, and other stakeholders. Such attention to detail, although essential for building wide and deep support for a future low-carbon economy, has so far been well beyond the ability of politicians stuck in Canberra’s toxic climate policy culture.

In all, the Paris Agreement, although voluntary, can be thought of as a global climate safety net held by all nations. This inclusiveness means that Australia will no longer be unable to point to the absence of other states as an excuse for its recalcitrance. It will increasingly be held to account by other nations, and the need for meaningful action will become ever more irresistible, as the net gradually tightens.

Peter Christoff does not work for, consult, own shares in or receive funding from any company or organization that would benefit from this article, and has disclosed no relevant affiliations beyond the academic appointment above.

Water use for transport is significant. Edited from Wikimedia commons, CC BY-NC-SA

Melbourne’s transport uses 311 billion litres of water each year - equivalent to flooding the city’s centre 8 metres deep. That’s just one of the findings of our study looking at how much water different modes of transport use.

We found that cars are the most water-intensive mode of transport, using on average 6.4 litres of water per passenger, per kilometre. Diesel trains use 5.2L per passenger-kilometre (pkm) and electric trains use the least, at 3.4L per pkm.

This means that a typical commuter can use between 140L and 350L of water per day to travel to work and back. This is at least as much as a Melbourne resident’s daily household water use of 160L.

Water use is thus a significant part of transport sustainability, but it is often ignored in favour of focusing on energy use and greenhouse emissions. So what can we do to stop transport draining our water resources?

How is water used in transport?

Water is needed in nearly all aspects of transport. It’s needed to make cars, to produce fuels, to replace tyres, and to build roads, among other processes.

Similarly, trains require water for the administration of the public transport network, manufacturing engines and rolling stock, constructing railways and stations, and providing customer services.

So the entire supply chain supporting the delivery of passenger transport needs to be considered in evaluating total water use.

To estimate the total water intensities of different transport modes, we used input-output analysis. This statistical technique models the entire economy of a nation or region, capturing the economic transactions between each sector of the economy and another.

The resulting input-output tables are then extended with environmental data that allow us to estimate the environmental intensity of each sector - in this case the amount of water per dollar. Using detailed financial expenditure data for each transport mode, we can figure out how much water is being used.

How much water is Melbourne’s transport using?

Transport in Melbourne is dominated by cars, as in all Australian cities and many others around the world. This is in contrast to urban centres such as Copenhagen, which relies heavily on bikes.

Melbourne does offer a range of public transport systems, including regional and metropolitan trains. These represent the large majority of public transport trips. For these reasons we focused on petrol cars and trains as the main passenger transport modes. The infographic below summarises our findings.

Water requirements of passenger transport modes in Melbourne, Australia.

A 50km round trip to work by car requires 320L of water – more than two months of drinking water for a single person. Travelling alone by car is the most water-intensive way to travel.

For train travel, the water use associated with transporting 175 people for 20km in an electric train would be equivalent to having 6cm of water on the floor of the train at arrival. This is equivalent to more than three years worth of drinking water for one person.

You can imagine trains filling up with water relatively quickly throughout the day.

Beyond Melbourne

While our study focused on Melbourne, the water intensity of transport modes is also likely to be significant in other cities of Australia and globally. This is because we need a significant amount of water for many manufacturing processes, water supply, electricity generation, fuel production and for other products and services. A study on the water requirements of road vehicles in Finland found similar water intensities for cars and supports this argument.

But it is important to highlight that there is uncertainty in the data. One of the most influential factors is the number of people per vehicle. This is typically very low for cars (around 1.2 people in Melbourne ) and relatively high for trains (around 55-66% full).

This could be improved by car-pooling. We found that if five people travelled together in a car, cars become the most efficient mode of transport. Car-pooling is far from being used at its full potential, but the recent advent of ride-sharing companies can help change this.

However, cars are probably not the best solution as they lead to other negative impacts on the built environment. These include favouring low-density suburban sprawl, air pollution, threatening street life and requiring large costs for infrastructure and land-use.

If this is the case, how can we reduce the water requirements associated with our travel?

Moving forward

Reducing the water requirements associated with passenger transport is a shared responsibility for travellers and transport providers.

There are two main things you can do as a commuter.

First, ditch cars in favour of public transport, which uses less water and resources per person. If public transport isn’t available, make sure your car contains as many passengers as possible.

Second, walk or cycle more often. Both significantly reduce indirect requirements for water, energy use and greenhouse gas emissions.

It could be argued that with more physical activity comes greater need for water and food, which in turn requires huge amounts of water to produce. However, the health benefits of active transport and the resulting savings in public health schemes probably outweigh this additional demand. Some further research is needed to determine whether this is truly the case.

For public transport providers, it is critical to ensure that the entire supply chain is managed better. While water efficiency in administrative buildings is praiseworthy, the majority of the demand occurs further upstream in the supply chain. This can be accomplished through supply chain management. For example, providing incentives for subcontractors and partners to implement integrated water saving strategies.

It is clear that further research is needed to better understand and assess water use associated with transport. More cities and modes of transport need to be assessed to provide a more comprehensive understanding of water use. This will ultimately contribute to reducing our total use of water and help preserve the natural systems on which we depend.

André Stephan receives funding from the Australian Research Council.

Robert Crawford receives funding from The Australian Research Council.

Leonardo DiCaprio’s new climate change documentary, Before the Flood, began streaming online this week. As a disaster risk scientist, I watched with intrigue.

While it doesn’t cover a lot of new material for those familiar with the topic, DiCaprio will undoubtedly reach a new audience given his star power and access to figures like Pope Francis and US President Barack Obama.

At the time of writing, the film has been watched more than 6 million times on YouTube alone. Clearly, it will make a significant contribution to the contemporary discussion around climate change, much like Al Gore’s An Inconvenient Truth a decade ago.

Leonardo DiCaprio’s latest work.

Coming in the same week that the Paris Agreement enters into force, the movie helps to set the stage for action to prevent the worst impacts of a global environmental crisis that is already well under way.

But as exciting as it is to see an A-list Hollywood star train his celebrity spotlight on this issue, it is important to critique some of the film’s underlying assumptions. Chief among these are the idea that “green growth” will allow us to have economic growth without environmental damage, and the notion that the politicians and corporations who helped compromise our planet can now be trusted to save it.

Denial and overconsumption

In making the film, DiCaprio spent three years travelling the globe to see the most severe impacts of climate change. He also discussed climate change’s causes, impacts and mooted solutions with leading environmentalists, scientists, innovators and politicians.

He found overwhelming scientific evidence that disaster is imminent. He also found a lobby that is determined to deny that humans are responsible, and a near-universal commitment to technocratic solutions.

While talking to climatologist Michael Mann about the denial movement’s well-funded and effective campaign to confuse the public, DiCaprio remarks: “If I was a scientist, I would be absolutely pissed every single day of my life.” (Presumably he means “pissed” in the American sense, rather than the UK/Australian usage.)

He goes on to trace the corporate sector’s funding of alternative and contrarian climate research, as well as the partisan politics at play in this movement.

One of the film’s most poignant moments takes place in India. DiCaprio’s discussion with environmentalist Sunita Narain turns to the issue of overconsumption in the United States, while poor countries are told they must embrace renewable energy. She insists:

Your consumption is going to really put a hole in the planet. We need to put the issue of lifestyle and consumption at the centre of climate negotiations.

Narain is left shaking her head as DiCaprio argues ruefully that Americans will probably never accept a change to their “standard of living”, a concept that is unavoidably linked to consumption.

Can green growth really save us?

A visit to the Tesla Gigafactory gives us a look at what is possible with today’s technology. Chief executive Elon Musk shares his vision for a clean energy transition, claiming that 100 Gigafactories could power the planet. However, he warns that:

…the fossil fuel industry is the biggest industry in the world. They have more money and more influence than any other sector… [but] if government sets the rules to favour sustainable energy, we can get there really quickly.

While the film captures the jubilant atmosphere at last year’s Paris climate negotiations, DiCaprio is clearly sceptical about the level of political will to challenge corporate power. The film argues that politicians generally follow public opinion, the implication being that they will only take on the fossil fuel sector if and when society demands it.

Yet sections of society have been demanding it for decades, and their outrage has routinely been dismissed. At this moment, protesters at Standing Rock, North Dakota are in a protracted standoff with police and private military over a planned oil pipeline that Native American tribes fear will harm local groundwater. President Obama’s suggestion of allowing the situation to “play out for several more weeks” speaks powerfully of the political establishment’s willingness to give armed backing to corporations.

Before the Flood lines up a series of leaders, scientists and innovators to tell us that we need to move faster towards sustainable energy. But their implied backing of the economic status quo of indefinite growth goes unchallenged, because DiCaprio sees such a challenge as impossibly radical. We therefore leave ourselves at the mercy of a technocratic response that has failed time and again.

A robust critique of “green growth”, and of the growth paradigm in general, would have been well within this film’s remit. Instead, it is presented as our only hope.

Likewise, the film neglects to challenge the implicit suggestion that the current crop of leaders and corporations are the best people to lead us into this green utopia.

Radical change

The film’s message is that we simply need to educate, organise and take action in our communities, and then politicians will follow suit. This downplays the influence of money in politics, and the reality that voting in many countries is an exercise in futility. Rhetoric aside, can we really trust the same political elite that have allowed such destruction on their watch?

The film’s intention to reach a mass-market audience might explain the editorial decision to sidestep the uncomfortable issue of economic growth. But this is to shirk a crucial responsibility. Less developed countries experiencing rapid growth are looking to the United States for leadership, but finding only hypocrisy.

DiCaprio tells a story that pins humanity’s hopes on cheaper, high tech renewable technologies, alongside political will. In a speech to the UN General Assembly, he pleads:

No more talk, no more excuses, no more ten-year studies. This is the body that can do what is needed, all of you sitting in this very hall. The world is now watching. You will either be lauded by future generations or vilified by them.

I wonder whether we have mistaken our wishes for reality – that we can just will an energy revolution into being without making any hard choices. Why else do we defend a system where multinational corporations’ right to profit comes before our health, livelihoods and environment?

Before the Flood offers us a choice between planetary destruction and the promised green tech revolution. But it doesn’t tell us about the third option: radical system change. Its advocates are vocal, but repressed. I, for one, am convinced that the scientific community must now rally to their cause.

Jason von Meding receives funding from the Australian Government.

Coral-eating crown-of-thorns starfish are helped by nutrient runoff. Crown of thorns image from www.shutterstock.com

The most recent report card on the Great Barrier Reef’s water quality highlighted major changes that need to be made to meet targets by 2018. Sediment and pollutant runoff from land use have increased 2-3 fold since 1850, largely driven by agricultural land clearing and grazing, while fertiliser used in sugar cane farming contributes to nitrogen runoff.

Runoff increases coral’s sensitivity to bleaching and disease, shifts the balance between coral and algae, leads to a build-up of pollutants in marine species that are long-lived or high in the food web, and increases the chances of crown-of-thorns starfish outbreaks.

Improving water quality will likely increase the health of reef organisms, and help reefs to bounce back from disturbances.

Government investment plans need to account properly for the total estimated value of the Great Barrier Reef and past progress in reducing runoff. An estimated A$500 million per year is needed to improve management action.

So what’s the best way to meet these targets? You won’t be surprised to find that scientists are working on the answer. But innovative projects fusing art and science are also appearing in north Queensland.

The problem of collective action

Like many environmental issues, runoff on the Great Barrier Reef is a classic example of a collective action problem. Collective action is at the heart of this issue in two ways.

First, the alongshore transport of sediment and runoff pollutants by currents means that the effects of managing runoff along one section of coastline may be felt elsewhere. The condition of the reef adjacent to a particular river mouth may not, therefore, necessarily reflect the land management within that river’s catchment.

Second, the health of the reef is dependent on other factors, such as bleaching driven by increased sea surface temperatures related to climate change. These are caused by many geographically remote activities (for instance, someone burning coal in London).

Collective action problems can be understood through US academic Garret Hardin’s famous “tragedy of the commons” theory. This theory states that self-interested individuals acting rationally may not behave in the best interests of the whole group.

Hardin used the example of a group of herdsmen allowing their cattle to graze a pasture that is running out of fodder. For an individual herdsman, the cost of removing cattle exceeds the benefit of leaving some pasture for the future, unless other herdsmen also agree to remove cattle.

Similarly, it takes an exceptional individual to reduce their runoff impacts, in light of the agricultural benefits to be gained from activities that increase runoff volume and decrease its quality (such as land clearing and use of fertilizers). This is particularly the case when others are not acting to abate their own activities.

Many farmers say that the Reef 2050 target to reduce runoff by 80% by 2025 is not economically viable. But without acting now, our metaphorical common (the inshore Great Barrier Reef) will continue to degrade.

Best environmental practice

Agriculture is a social and cultural activity, just as much as it is a process of environmental engineering, and the push to transform farming practices needs to recognise this. Top down incentive schemes do have some impact, but could there be a better way?

For instance, for sugar cane growers, the Smartcane Best Management Practice (BMP) Guidelines are an attempt by the industry to shift farming practices towards compliance with government directives to reduce run-off impacts on the reef.

The Smartcane BMP guidelines aim to improve farming practices through seven principles:

1. Soil health and plant nutrition management

2. Pest, disease and weed management

3. Drainage and irrigation management

4. Crop production and harvest management

5. Natural systems management

6. Farm business management

7. Workplace health and safety management

As with many corporate social responsibility initiatives, growers who volunteer for Smartcane BMP are required to assess their current practices and set benchmarks for improvement in order to receive accreditation that indicates good environmental practice. There are clear marketing and, in many cases, cost-cutting benefits that motivate farmers to participate.

This has driven some examples of good practice within the farming community. However, as the 2015 report card shows, “only 23% of sugarcane land was managed using best management practice systems”, which is inadequate for achieving the Reef 2050 goal of an 80% reduction in dissolved nitrogen loads from agricultural runoff by 2025.

Motivating farmers

One project which engages with this problem is Sugar vs the Reef? by artists Lucas Ihlein, Kim Williams and Ian Milliss. This project is based on the idea that there is a greater chance of influencing farming practices if the desire to improve environmental performance comes from within the farming community. Innovation is celebrated from below by staging public collaborative events to generate dialogue about agriculture’s complex social and environmental interactions.

Innovative Mackay farmers Simon Mattsson and Allan Maclean in a dual crop of sugar cane and sunflowers. The sunflowers shade out weeds, break the sugarcane monocrop by diversifying soil biology, and attract a lot of attention, triggering public discussions about the crucial role of soil health in reducing runoff to the Great Barrier Reef. Photo by Lucas Ihlein

For example, over the next two years, the project will coordinate a collaboration between Mackay Botanical Gardens, sugar cane farmers and community members to plant a dual crop of sunflowers and sugar cane as a highly visible work of “land art”.

This crop - whose cycle of planting, growth and harvesting will exceed the minimum standards of BMP - will stretch over four hectares near the centre of Mackay. Over two years, the project will engage sugarcane farmers, artists, high school students, members of the Australian South Sea Islander community, the Greater Whitsunday Food Network, soil and reef scientists, as well as the Great Barrier Reef Marine Park Authority.

While it is easy to point the finger at agricultural practices as a major cause of poor water quality in the inner waters of the Great Barrier Reef, change will be slow until the complex social factors that shape modern farming are recognised. This requires deeper engagement with the varied cultures of farming.

Sarah Hamylton is a council member of The Australian Coral Reef Society

Lucas Ihlein receives funding from the Australian Research Council (ARC) for his DECRA project "Sugar vs The Reef?: Socially-engaged art and urgent environmental problems."

Pressure is mounting for Adani’s Carmichael coal mine to proceed in inland Queensland. Recently the state government quietly gave the project “critical infrastructure” status to prioritise its development.

Providing this level of government status to a private enterprise is unusual – the last time it happened was in the early 2000s, and it is usually reserved for projects associated with national security, public education and health.

In response to delays and finance issues, Adani has also reportedly scaled back its initial proposal to increase the mine’s viability. There are also growing political calls to weaken the ability of environmental groups to challenge infrastructure projects.

Others have commented on the mine’s issues around employment, finance, and indigenous and rural communities. But as ecologists, there are four good reasons why we believe the mine should not go ahead.

Climate change

To meet the obligations under the Paris climate agreement to limit warming to well below 2℃, it is widely accepted that 90% of Australia’s coal will need to stay in the ground.

The proposed extraction of 2.3 billion tonnes of coal from the Carmichael mine flies in the face of global efforts to stop climate change. The emissions from the coal from this one mine would exceed 0.5% of the entire global carbon budget – the total amount of carbon than can be emitted without exceeding 2℃ warming.

Put another way, the 4.7 billion tonnes of greenhouse gas emissions associated with the mine will be equivalent to nine times Australia’s overall emissions in 2014.

Yet these emissions have been given little consideration in the mine’s approval process. Adani’s Environmental Impact Statement makes little reference to the mine’s “downstream” emissions, and Australia’s former environment minister Greg Hunt, in his reasons for approving the mine, said the emissions would be “managed and mitigated through national and international emissions control frameworks”, including in those countries that import the coal.

Following an appeal challenging Hunt’s assertion that these emissions would have no directly quantifiable impact on the Great Barrier Reef, the Federal Court found that the minister was entitled to find that the burning of the coal will have no relevant impact on the reef.

The Great Barrier Reef

The shipping of coal from the Carmichael mine is contingent upon redeveloping the shipping port at Abbot Point, which requires dredging the seabed.

Following public opposition to dumping dredge spoil at sea, the most recently approved proposal is to dredge 1.1 million cubic metres of the seabed and dump the spoil on land next to the Caley Valley Wetlands.

The wetlands are important habitat for at least 22 migratory shore birds listed under the national environmental legislation, so the current plan is still contentious.

The current plan to dump the dredge spoil on land still won’t save the reef because the actual dredging process removes the seabed, along with the seagrass and animals that survive there.

Dredging also releases fine sediments, reducing water quality while smothering surrounding seagrass beds and coral reefs, with some models predicting the spread of fine sediments up to 200km from where the activity took place, within 90 days.

Corals exposed to dredge material are twice as prone to suffer disease. Improving water quality is a key factor for increasing the resilience of coral reefs to major bleaching events.

Water

The Carmichael Mine as currently proposed would extract 12 billion litres of water each year. Removing this water to access the coal seam will reduce water pressure in the aquifer (rock that stores water underground), with knock-on effects. The mine is situated close to the Great Artesian Basin, a key resource for agriculture across inland Australia

For instance, this drawdown could reduce water reaching the Mellaluka and Doongmabulla Springs Complexes, which have exceedingly high conservation value. These springs are some of the largest examples remaining and provide habitat for many species of specialised plants that are only known from spring-fed wetlands.

If the springs go dry, even temporarily, endemic species will not survive and will become extinct at the site.

Removing groundwater is expected to increase the duration of zero- or low-flow periods in the Carmichael River system. The communities and ecosystems in the region are already highly reliant on groundwater, due to variable surface waters. This could also affect the acidity and salinity of soils.

Clearing the land for the mine itself – an area equivalent to Queensland’s Moreton Island - will likely reduce local rainfall considerably.

Due to the high uncertainty surrounding groundwater, the independent scientific committee recommended improvements in groundwater modelling and monitoring before proceeding with the project. The high degree of uncertainty and inadequate treatment of groundwater impacts in the Environmental Impact Statement were the subject of legal proceedings in the Land Court in 2015.

Threatened species

The Carmichael mine site is home to the largest known population of the endangered southern Black-throated finch (Poephila cincta cincta), which has lost 80% of its former habitat.

The intact areas of continuous habitat in this region - such as that at the mine site - have so far remained in good condition and relatively free of the invasive weed species that are contributing to the finch’s decline in other parts of its range.

The Black-throated Finch Recovery Team highlighted their concern over the Carmichael development with state and federal agencies.

Adani has proposed to offset the loss of finch habitat resulting from the mine by protecting alternative, nearby habitat. But losing the best remaining habitat means the most viable population will be compromised. Experts have warned that offseting the loss of habitat from mine development will not avoid serious detrimental impacts on the finch.

Keeping this habitat intact, continuous and unfragmented will be key to maintaining its suitability for the finch. The only way to avoid severely impacting the finch is to avoid destroying its high-quality habitat – which would mean not digging the mine in these areas.

A brighter future

Giving the mine “critical infrastructure” status allows special dispensations to ignore normal approval processes. And this decision sends a signal to the wider community that this type of short-term thinking is front and centre in the state government’s mind.

Given the clear environmental impacts this mine will have, not just for the region but for the whole planet, we question the effectiveness of Australia’s current environmental laws that have allowed it to be approved. We believe it is time to place the entire social and environmental costs and benefits of this mine on the public table, and ask the question of the politicians who are meant to make decisions in our best interest: is the short-term profit of selling some coal worth it?

This article was written with the help of Claire Stewart and Courtney Jackson, students in the Masters of Conservation Science program and members of the Green Fire Science Lab at the University of Queensland.

April Reside receives funding from NESP Threatened Species Recovery Hub. She is a scientific advisor for the Black-throated Finch Recovery Team and is on Birdlife Australia's Research and Conservation Committee.

Bonnie Mappin receives funding from the University of Queensland Research Scholarship.

James Watson receives funding from the Australian Research Council. He is the Director of Science and Research Initiative of the Wildlife Conservation Society.

Sarah Chapman is supported by an APA Scholarship. She is a PhD candidate at the University of Queensland.

Stephen Kearney is supported by an APA Scholarship and has received funding from NESP Threatened Species Recovery Hub.

Aquaculture is in the spotlight again, with an ABC investigation raising concerns over the sustainability of the expansion of Tasmania’s salmon-farming industry.

Controversies over fish farming are newsworthy and emotive, particularly when company profits and communities are at stake. Unfortunately, independent scientific evidence is often used selectively or even ignored in these debates.

Science is an essential tool for managers and regulators when planning industry expansion, and Australia’s aquaculture industry does have a strong research base.

Fish farming can be sustainable, but only if it takes proper account of scientific research – and only if that research moves fast enough to give an up-to-date picture of the risks.

Demand for sustainable aquaculture

The ever-growing demand for seafood, combined with the limited opportunity to increase catch from wild fisheries, means we need more aquaculture. Farming already produces roughly 50% of the global seafood supply, and farmed fish production now exceeds that of farmed beef.

Intensive aquaculture is relatively new, with supply rising tenfold since the mid-1980s. It is thus unique among food production sectors in that its initial expansion has taken place in an era of unprecedented scrutiny from government, environmentalists and the community.

This scrutiny is warranted, given that many fish farms are in coastal waters considered as a multi-use, common resource. In Australia, the industry is subject to high environmental standards and constantly evolving management.

Intensive aquaculture has several inherent advantages over other forms of agriculture (besides the intrinsic health benefits of seafood). These include efficient food conversion (it takes just 1.3kg or less of feed to produce 1kg of salmon, compared with 1.8kg for chicken and 2.6kg for pork); relatively limited use of fresh water; and the absence of fertilisers.

However, there are also significant sustainability challenges, including limiting marine feed ingredients; waste management; the use of drugs, colourants and other chemicals; impacts on wild marine species; management of fish health and welfare; site selection; and societal attitudes.

The aquaculture research community is acutely aware of these challenges. At a World Aquaculture conference in Adelaide in 2014, the program was dominated by issues related to sustainable development.

Planning for the future

In the forseeable future, world aquaculture production is projected to grow at least at its current and long term rate of 6.5% a year. Australia’s industry, while representing less than 0.1% of world production, is growing even faster: more than 7% a year over the past decade.

Given cost constraints, this future expansion will be mostly inland or in coastal marine environments. Scientific input will be crucial if this expansion is to be managed in a sustainable way.

For example, coastal aquaculture operations are exposed to conditions that create good years and bad years. Understanding the spatial and temporal variation in these conditions is critical. It is not in the industry’s interest to risk growing fish in marginal conditions.

Conditions are also becoming more challenging as a result of climate change – the oceans off Australia’s southeast are among the fastest warming on the planet.

Enlightened aquaculture businesses are trying to anticipate these conditions by working with scientists including CSIRO and the Bureau of Meteorology to understand future environmental risks on a range of timescales.

Seven-day ocean forecasts and medium-term outlooks covering several months will help the industry make decisions about cage locations, stocking density, diet, disease management, and when to harvest.

Monthly forecast of ocean temperatures for the east coast of Tasmania for the coming months Author provided

Meanwhile, longer-term planning, on time scales of years and decades, will be informed by climate models. For example, the industry can aim to breed fish to cope with changing conditions such as warmer water.

Of course, forecasts are never 100% accurate, meaning that aquaculture businesses still need to account for risk and uncertainty.

Planning for now

Science is clearly crucial for effective future planning. But it is also important to ensure that current management is the best it can be, and that current risks are managed.

In the case of finfish aquaculture, the potential for localised impacts on the seabed around sea cages is well known, and monitoring and management strategies well established.

The potential for adverse effects on the water in and around cages is also important, and water column monitoring is increasingly a management requirement.

Broader ecosystem interactions – such as changes in fauna and flora on reefs around cages – are progressively being recognised as an issue for many aquaculture regulators and managers.

As scientists’ understanding of these risks increases, regulators and managers can implement strategies to protect a broader suite of environmental assets and values.

However, there is no “one size fits all” management approach for this rapidly growing industry, and strategies need to be considered in the local context (ecological, social and economic). Science can provide a better understanding of a particular scenario, but it is up to managers to use this information wisely – and to exercise caution where risks are not well understood.

Fast responses

Management may aspire to be “best practice”, but it is important to recognise that this does not mean that it will be static or finite. Management should respond to changes in the environment (both natural and social) and should adjust as the science and understanding develops.

It is important to acknowledge the different but complementary roles that science and management play in aquaculture planning. Scientists seek to understand the situation (such as the current or future environmental conditions) and share that understanding impartially and objectively. Regulators and managers need to make decisions with a much broader mandate, and as such need to consider factors beyond the science alone. Good planning needs to recognise the value of both.

Aquaculture development and policy needs to be able to trust the science, which in turn, must be delivered in a timely manner, to ensure long-term sustainability of this industry.

Graham Mair receives funding from FRDC, the commonwealth government and industry for research related to aquaculture. He is a director of Australian Seafood Industries (ASI) Ltd. which is a company that manages a selective breeding program for Pacific Oysters. Graham Mair is a member and Past-President of the World Aquaculture Society which is a professional society that has no advocacy role.

Alistair Hobday is involved in research developing short-term, seasonal and climate scale forecasts which are used by marine industries, including salmon aquaculture. This work has been funded by FRDC, CSIRO, BOM, and co-investment from industry associations.

Catriona Macleod is an environmental scientist with a focus on environmental impact assessment and sediment remediation in the coastal zone and as such has been involved with research related to salmon aquaculture. She has received funding from a number of different government and philanthropic sources, including the FRDC and the Tasmanian state government.