The Conversation

Terese Pagh eating a banana flavoured eXo Protein bar made out of cricket powder. provded by The Gateway Bug

I’ve had the privilege of getting a sneak preview of a movie called The Gateway Bug, which is a documentary about feeding humanity in an uncertain age. It will be shown in Melbourne next weekend as part of the Melbourne Documentary Film Festival.

I wrote that eating insects is a good idea back in 2013, shortly after the Food and Agriculture Organization (FAO) released a report suggesting that using insects for food and feed would increase food security for our planet.

Following the publication of that article, I was contacted by people who wanted to know how to start farming insects. They were looking for people to contact, for information on regulations. I was invariably unhelpful. I didn’t know the answers, and felt inadequate, but now I know that nobody knew the answers back then. We were at the very beginning of a journey.

The Gateway Bug is a documentary about that journey, following the nascent industry in North America producing insects for human consumption. Insects provide an alternative to our current food systems that use too much water, too much land, produce mountains of organic waste and create vast clouds of greenhouse gases.

Film makers Johanna B. Kelly (director) and Cameron Marshad (cinematographer and editor) began making the film in 2015 at the first meeting of the American Edible Insect Coalition in Detroit. By interviewing 50 professionals in this new industry, the film makers have claim that they can convert viewers into activists.

The film begins with a rush of frightening statistics about the dangers surrounding the future of food, made entertaining by their choice of music: Pollution by Tom Lehrer. Within the first 10 minutes they have brought the audience up to speed on the problem with our food systems. They spend the next hour and a quarter listening to the people who are working on potential solutions and providing detail about the challenges they face.

Surprisingly, convincing people to understand the potential health benefits and to like the taste of insects does not seem to be one of those challenges. There are no signs of disgust on the faces of people eating insects for the first time, who say they taste like chips or popcorn. A protein powder made from crickets is said to be “nutty with a hint of shrimp”. When crickets were offered as a topping on gourmet hot dogs in Youngstown Ohio, the restaurant struggled to keep up with demand.

No, the challenges were logistic rather than ideological. Cricket farms must find feed that does not compromise the taste of their product. Grinding the grain to a powder fine enough for baby crickets and caring for thousands of charges at a time is labour intensive. Sadly, one business goes under when millions of crickets die off due to contaminated town water.

What I found deeply surprising was the diversity of viewpoints of the people involved. One California business, which started by growing crickets on spent mash from a nearby brewery, gave up when it became apparent that their product could not be used as fish feed in the aquaculture industry.

Tyler Isaac, co-founder of Slightly Nutty, closed his business in 2016 because, “..we did not want to feed rich millennials cricket powder”. For him, the main problem is the unsustainable food system and unless he was changing that, he did not feel like he was making a difference.

Other companies are all about finding ways to get Americans to eat crickets: as protein bars (eXo), in chocolate bars (Chapul), or as chips quaintly renamed Chirps (Six foods). Also concerned about climate change, the lack of water resources, and food systems, the people that run these companies are nevertheless content to use their products as a gateway to using bugs in everyday foods.

I loved the way the film makers used old footage to express certain attitudes toward food and insects. It cleverly sent the message that although the words sounded perfectly reasonable, these ideas are already part of our past. The graphics were simple and useful, expressing concepts in a way the viewer didn’t have to work too hard to understand.

The Gateway Bug is really a discussion of food and how critical it is to our future on this planet. That may sound somewhat trite, but this film makes you sit down and think seriously about where our food comes from and where it will come from in a more crowded future earth.

Before seeing this movie, I didn’t even know that “entomophagist” was a word, but as an advocate of entomophagy, I suppose I am one. I was surprised and moved by this documentary, which did not pull any punches but also did not preach or condescend. But beware, after watching it, you are probably going to want to eat some bugs.

The Gateway Bug will be screened at Cinema Nova, Melbourne on 16 July 2017 at 3 pm. Buy tickets here

In a somewhat surprising decision, UNESCO ruled this week that the Great Barrier Reef – one of the Earth’s great natural wonders – should not be listed as “World Heritage in Danger”.

The World Heritage Committee praised the Reef 2050 Long-Term Sustainability Plan, and the federal minister for the environment, Josh Frydenberg, has called the outcome “a big win for Australia and a big win for the Turnbull government”.

But that doesn’t mean the Reef is out of danger. Afforded World Heritage recognition in 1981, the Reef has been on the warning list for nearly three years. It’s not entirely evident why UNESCO decided not to list the Reef as “in danger” at this year’s meeting, given the many ongoing threats to its health.

However, the World Heritage Committee has made it clear they remain concerned about the future of this remarkable world heritage site.

The reef is still in deep trouble

UNESCO’s draft decision (the adopted version is not yet releasesd) cites significant and ongoing threats to the Reef, and emphasises that much more work is needed to get the health of the Reef back on track. Australia must provide a progress report on the Reef in two years’ time – and they want to see our efforts to protect the reef accelerate.

Right now, unprecedented coral bleaching in consecutive years has damaged two-thirds of Australia’s Great Barrier Reef. This bleaching, or loss of algae, affects a 1,500km stretch of the reef. The latest damage is concentrated in the middle section, whereas last year’s bleaching hit mainly the north.

Pollution, overfishing and sedimentation are exacerbating the damage. Land clearing in Queensland has accelerated rapidly in the past few years, with about 1 million hectares of native vegetation being cleared in the past five years. That’s an area the size of the Brisbane Cricket Ground being cleared every three minutes.

About 40% of this vegetation clearing is in catchments that drain to the Great Barrier Reef. Land clearing contributes to gully and streambank erosion. This erosion means that soil (and whatever chemical residues are in it) washes into waterways and flows into reef lagoon, reducing water quality and affecting the health of corals and seagrass.

Landclearing also directly contributes to climate change, which is the single biggest threat to the Reef. The recent surge in land clearing in Queensland alone poses a threat to Australia’s ability to meet its 2030 emissions reduction target. Yet attempts by the Queensland Government to control excessive land clearing have failed – a concern highlighted by UNESCO in the draft decision.

Land clearing can lead to serious hillslope gully and sheet erosion, which causes sedimentation and reduced water quality in the Great Barrier Reef lagoon. Willem van Aken/CSIRO A time for action, not celebration

The Reef remains on UNESCO’s watch list. Just last month the World Heritage Committee released a report concluding that progress towards achieving water quality targets had been slow, and that it does not expect the immediate water quality targets to be met.

The draft decision still expressed UNESCO’s “serious concern” and “strongly encouraged” Australia to “accelerate efforts to ensure meeting the intermediate and long-term targets of the plan, which are essential to the overall resilience of the property, in particular regarding water quality”.

This means reducing run-off of sediment, nutrients and pollutants from our towns and farmlands. Improving water quality can help recovery of corals, even if it doesn’t prevent mortality during extreme heatwaves.

The Great Barrier Reef is the most biodiverse of all the World Heritage sites, and of “enormous scientific and intrinsic importance” according to the United Nations. A recent report by Deloitte put its value at A$56bn. It contributes an estimated A$6.4bn annually to Australia’s economy and supports 64,000 jobs.

Excessive landclearing in Queensland, which looks like being a core issue in the next state election, has been successfully curbed in the past, and it could be again.

But the reef cannot exist in the long term without international efforts to curb global warming. To address climate change and reduce emissions, we need to act both nationally and globally. Local action on water quality (the focus of the Reef 2050 Plan) does not prevent bleaching, or “buy time” to delay action on emissions.

We need adequate funding for achieving the Reef 2050 Plan targets for improved water quality, and a plan to reach zero net carbon emissions. Without that action, an “in danger” listing seems inevitable in 2020. But regardless of lists and labels, the evidence is clear. The Great Barrier Reef is dying before our eyes. Unless we do more, and fast, we risk losing it forever.

James Watson receives funding from the Australian Research Council and the National Environmental Science Programme. He is the global Director of the Science and Research Initiative at the Wildlife Conservation Society and President of the Society for Conservation Biology.

Martine Maron receives funding from the Australian Research Council, the National Environmental Science Programme, the Science for Nature and People Partnership, and the NSW Office of Environment and Heritage. She is a Director of BirdLife Australia and a Governor of WWF Australia.

Climate teams: if countries pooled resources, they could support a low-emission transformation. CC BY-ND

Despite the US withdrawal from the 2015 Paris Agreement on climate change, other countries, including New Zealand, remain committed to cutting their greenhouse gas emissions.

In our report, we explore how New Zealand, a trailblazer for emissions trading, might drive a low-emission transformation, both at home and overseas.

Turning off the tap

Emitting greenhouse gases is a lot like overflowing a bathtub. Even a slow trickle will eventually flood the room.

The Paris Agreement gives all countries a common destination: net zero emissions during the second half of the century. It is also an acknowledgement that the world has only a short time to turn the tide on emissions and limit global temperature rise to below two degrees. The sooner we turn down the tap, the more time we have for developing solutions.

Time is running out on meeting the goal of keeping global temperature rise below two degrees. from Unsplash, CC BY-ND

New Zealand’s 2030 commitment is to reduce emissions 30% below 2005 levels (11% below 1990). In 2015, our emissions (excluding forestry) were 24% above 1990 levels. The government projects a gap of 235 million tonnes between what has been pledged and what New Zealand will actually emit in the period from 2021 to 2030.

Reducing emissions rapidly enough within New Zealand to achieve our Paris commitment could be extremely expensive, and even at a cost of NZ$300 per tonne, the target could not be met through domestic action alone.

International emission reductions help bridge the gap. New Zealand could turn off its own greenhouse gas tap while supporting other countries to do the same.

Joining forces across borders

In the past, New Zealand relied heavily on the global Kyoto carbon market and purchased international emission reductions using the New Zealand Emissions Trading Scheme (ETS). Some ETS firms bought low-cost overseas Kyoto units of questionable integrity while domestic emissions continued to rise.

In 2015, New Zealand pulled out of the Kyoto carbon market and its ETS is now a domestic-only system.

Under the Paris Agreement, carbon markets have changed in three important ways:

• Currently, international emission reductions can be traded only from government to government. It is no longer possible for NZ ETS participants to buy international units directly from the market.

• International emission reductions sold as offsets to other countries will have to be additional to the seller’s own Paris target.

• Countries have flexibility to trade international emission reductions through arrangements outside of the central UN mechanism which is at an early stage of development.

A new approach to reducing emissions

What does this mean for New Zealand? First, we cannot and must not rely on international markets to set our future domestic emission price.

Second, as both taxpayers and responsible global citizens, we need to decide where to fund emission reductions. Most mitigation opportunities are in developing countries. The benefits of investing in lower-cost reductions overseas need to be weighed against the costs of deferring strategic investment in New Zealand’s own low-emission transformation.

Third, we need an effective mechanism to direct New Zealand’s contribution to mitigation overseas.

In collaboration with others, Motu researchers are prototyping a new approach: a results-based agreement between buyer and seller governments within a climate team.

For example, New Zealand could partner with other buyers – such as Australia, South Korea or Norway – to pool funding at a scale that provides incentives for a country with a developing or emerging economy – such as Colombia or Chile – to invest in low-emission transformation beyond its Paris target. These countries could then create a more favourable environment for low-emission investment – including by New Zealand companies.

Emissions trading could play an important role in New Zealand’s transition to a low-emissions economy. from Unsplash, CC BY-ND Retooling the ETS for domestic decarbonisation

So far, New Zealand has been moving at speed but in the wrong direction, relying heavily on international emission reductions to meet its targets from 2008 through 2020 while domestic emissions continued to rise. Gross emissions (excluding forestry) are projected to climb 29% above 1990 gross emission levels by 2030 under current measures. This is a far cry from our 2030 Paris target of net emissions of 30% below 2005 gross emission levels (11% below 1990).

New Zealand’s ETS has an important role to play in achieving a successful low-emission domestic economy, but it needs to be properly equipped.

Unlike other financial markets, the purpose of an ETS market is more than price discovery, resource allocation and liquidity. It is designed to create a change in behaviour to reduce emissions. Prices are driven not just by the interplay of demand and supply, but by current policy decisions, emission reduction opportunities, and expectations about future decisions and opportunities.

Since de-linking from the Kyoto market in mid-2015, NZ ETS participants have had no certainty on how to invest. They need clear near-term signals for unit supply and cost and predictable processes for longer-term decision making.

Five changes to make the emissions trading work

1. Introducing a cap (fixed limit) on NZ ETS units sold or freely allocated by the government will define supply and enable the market to set an efficient price. In the past, the NZ ETS borrowed the global Kyoto cap, which essentially allowed unlimited domestic supply. The Kyoto cap is no longer available and we have committed to reducing domestic emissions.

2. Establishing a price band will provide a minimum and maximum emission price limit, set by government. A price floor will guarantee a minimum return on low-emission investment and a price ceiling will safeguard against upside price shocks. When the floor and ceiling are far apart, the market has latitude when setting the price. The closer they are, the more the government manages the price. The price band will be implemented at auction and replace the current fixed-price option set at NZ$25 per tonne.

3. Fixing both the cap and the price band for five years and extending them by one year each year will provide short-term certainty. The government will also need to set indicative trajectories for caps and price bands for a further 10 years in alignment with its decarbonisation objectives. This will enable long-term decision-making.

4. Given the technical complexity of the ETS, we recommend that an independent body be tasked with advising government on ETS supply and price settings. Ultimately however, decisions on caps and price bands are political and therefore should be taken by government, with transparency and public accountability.

5. The era of top-down carbon markets, unlimited unit supply and rising domestic emissions has ended. Right now, only governments can purchase international emissions reductions. In the longer term, ETS participants may also be able to do so. However, the quantity must be limited and displace other supply under the cap to avoid devaluing domestic investment and disrupting New Zealand’s progress toward decarbonisation. All international emission reductions applied toward New Zealand’s targets must be quality assured to manage risks with environmental integrity.

These adjustments can be achieved through practical legislative amendments and regulation. There is merit in implementing these changes as soon as possible so that low-emission investors and emitters can get on the road.

Setting the ambition of domestic ETS caps and price bands can be politically challenging. That is why New Zealand skipped this step the first time around and borrowed the Kyoto ones instead. Under the Paris Agreement, New Zealand needs to establish a resilient policy architecture with cross-party support that offers predictable processes to guide future political decision making. It’s time for us to forge our own pathway to a successful low-emission economy.

This article was prepared by Suzi Kerr, Catherine Leining and Ceridwyn Roberts at Motu Economic and Public Policy Research. The supporting paper was funded by the Aotearoa Foundation and informed by participants in Motu’s ETS Dialogue. The content does not necessarily represent the views of or endorsement by ETS Dialogue participants, their organisation or the funder.

Suzi Kerr is a Senior Fellow at Motu Economic and Public Policy Research Trust, a not-for-profit research organisation in New Zealand, and an adjunct professor at Victoria University of Wellington. Motu’s work through the ETS Dialogue on reforming the NZ Emissions Trading Scheme has been funded by the Aotearoa Foundation.

This June was the seventh-warmest and second-driest on record for Australia. Parts of the southwest and southeast saw record dry conditions as frontal systems passed further south than normal and high pressure exerted its influence on the continent.

Australia’s second-driest June on record saw unusually dry conditions over most of the continent but more rain than average for Sydney and northeast New South Wales. Bureau of Meteorology

While many of us will have enjoyed warm, dry weather, farmers in the south of the country will be concerned at the lack of winter rain for their crops. Winter is the dominant season for rainfall, especially in the southwest of the continent, so a return to wetter conditions would be welcome.

There are already indications of drought developing across the west coast of Western Australia and in other areas of the country.

Did climate change play a role?

To deduce whether climate change had an influence on this particular event, I used two sets of climate model simulations: one representing the world of today and another representing a world without human influences (that is, with pre-industrial greenhouse gas concentrations).

I compared the likelihood and magnitude of dry Junes in the two sets of simulations to determine the net effect of human-caused climate change.

I looked at the climate change influence on very dry Junes (such as the one we’ve just experienced) both for Australia as a whole, and for the southeast, which had its driest June on record. Both of these areas received well below half of their average June rainfall in June 2017.

Southeast Australia had its driest June on record this year. Bureau of Meteorology

For Australia-wide June rainfall, I found a clear climate change signal towards drier conditions.

According to my analysis, climate change has increased the likelihood of very dry Junes by at least a third. The driest Junes now are about 12% drier than they would be in the absence of human greenhouse emissions.

When I looked at southeast Australia, however, I found that the influence of climate change is less clear.

My analysis suggested that climate change has probably increased the chance of dry conditions, although there is more uncertainty than for Australia as a whole.

That said, the driest Junes appear to be drier in the world of today than they would have been without climate change, by about 8% in the case of southeast Australia.

It’s not surprising that the result for southeast Australia is less distinct. Generally speaking, the smaller the area, the harder it is to detect an influence of climate change, as there is more year-to-year variability.

What can we expect in future?

The Paris Agreement aims to hold global warming well below 2℃ and preferably at around 1.5℃ above pre-industrial average temperatures. For context, we have had a little over 1℃ of global warming so far, so we’re more than two-thirds of the way to the 1.5℃ target already.

Under either a 1.5℃ or 2℃ global warming target, I project that dry Junes in Australia will become more frequent. For the southeast of the continent the picture is less clear, with high uncertainty in the change we might see.

Climate change is increasing the likelihood of dry Junes for Australia as a whole, but the signal is less clear over the southeast. The best estimate likelihoods are shown with 90% confidence intervals in parentheses. Author provided

The trend towards drier Junes across Australia is related to the southward shift in the storm track, the prevailing westerly winds that bring frontal weather systems across southern Australia. June 2017 is a very clear example of this effect.

Scientists use the Southern Annular Mode (SAM) to describe the position of the storm track. It has been trending towards more “positive” conditions, reflecting a poleward movement in the frontal systems which typically causes them to pass to the south of the Australian landmass.

These positive SAM phases bring drier conditions to most of Australia, but wetter conditions to coastal New South Wales. This is precisely what we have seen in June 2017.

As the effects of climate change intensify in the coming years, scientists expect to see the frontal systems that bring vital rainfall to the south of Australia moving further and further south. This increases the chance of Australia experiencing more dry Junes like the one just passed. Increasing temperatures will cause greater evaporation when there is rainfall, further exacerbating drought conditions.

You can find full details of the methods used in this analysis here.

Disclosure

Andrew King receives funding from the ARC Centre of Excellence for Climate System Science.

A new paper improves our estimate of the climate's sensitivity to carbon dioxide. NASA/Wikimedia Commons

One of the key questions about climate change is the strength of the greenhouse effect. In scientific terms this is described as “climate sensitivity”. It’s defined as the amount Earth’s average temperature will ultimately rise in response to a doubling of atmospheric carbon dioxide levels.

Climate sensitivity has been hard to pin down accurately. Climate models give a range of 1.5-4.5℃ per doubling of CO₂, whereas historical weather observations suggest a smaller range of 1.5-3.0℃ per doubling of CO₂.

In a new study published in Science Advances, Cristian Proistosescu and Peter J. Huybers of Harvard University resolve this discrepancy, by showing that the models are likely to be right.

According to their statistical analysis, historical weather observations reveal only a portion of the planet’s full response to rising CO₂ levels. The true climate sensitivity will only become manifest on a time scale of centuries, due to effects that researchers call “slow climate feedbacks”.

Fast and slow

To understand this, it is important to know precisely what we mean when we talk about climate sensitivity. So-called “equilibrium climate sensitivity”, or slow climate feedbacks, refers to the ultimate consequence of climate response – in other words, the final effects and environmental consequences that a given greenhouse gas concentration will deliver.

These can include long-term climate feedback processes such as ice sheet disintegration with consequent changes in Earth’s surface reflection (albedo), changes to vegetation patterns, and the release of greenhouse gases such as methane from soils, tundra or ocean sediments. These processes can take place on time scales of centuries or more. As such they can only be predicted using climate models based on prehistoric data and paleoclimate evidence.

On the other hand, when greenhouse gas forcing rises at a rate as high as 2–3 parts per million (ppm) of CO₂ per year, as is the case during the past decade or so, the rate of slow feedback processes may be accelerated.

Measurements of atmosphere and marine changes made since the Industrial Revolution (when humans first began the mass release of greenhouse gases) capture mainly the direct warming effects of CO₂, as well as short-term feedbacks such as changes to water vapour and clouds.

A study led by climatologist James Hansen concluded that climate sensitivity is about 3℃ for a doubling of CO₂ when considering only short-term feedbacks. However, it’s potentially as high as 6℃ when considering a final equilibrium involving much of the West and East Antarctic ice melting, if and when global greenhouse levels transcend the 500-700ppm CO₂ range.

This illustrates the problem with using historical weather observations to estimate climate sensitivity – it assumes the response will be linear. In fact, there are factors in the future that can push the curve upwards and increase climate variability, including transient reversals that might interrupt long-term warming. Put simply, temperatures have not yet caught up with the rising greenhouse gas levels.

Prehistoric climate records for the Holocene (10,000-250 years ago), the end of the last ice age roughly 11,700 years ago, and earlier periods such as the Eemian (around 115,000-130,000 years ago) suggest equilibrium climate sensitivities as high as 7.1-8.7℃.

So far we have experienced about 1.1℃ of average global warming since the Industrial Revolution. Over this time atmospheric CO₂ levels have risen from 280ppm to 410ppm – and the equivalent of more than 450ppm after factoring in the effects of all the other greenhouse gases besides CO₂.

Estimate of climate forcing for 1750-2000. Author provided Crossing the threshold

Climate change is unlikely to proceed in a linear way. Instead, there is a range of potential thresholds, tipping points, and points of no return that can be crossed during either warming or transient short-lived cooling pauses followed by further warming.

The prehistoric records of the cycles between ice ages, namely intervening warmer “interglacial” periods, reveal several such events, such as the big freeze that suddenly took hold about 12,900 years ago, and the abrupt thaw about 8,200 years ago.

In the prehistoric record, sudden freezing events (called “stadial events”) consistently follow peak interglacial temperatures.

Such events could include the collapse of the Atlantic Mid-Ocean Circulation (AMOC), with consequent widespread freezing associated with influx of extensive ice melt from the Greenland and other polar ice sheets. The influx of cold ice-melt water would abort the warm salt-rich AMOC, leading to regional cooling such as is recorded following each temperature peak during previous interglacial periods.

Over the past few years cold water pools south of Greenland have indicated such cooling of the North Atlantic Ocean. The current rate of global warming could potentially trigger the AMOC to collapse.

A collapse of the AMOC, which climate “sceptics” would no doubt welcome as “evidence of global cooling”, would represent a highly disruptive transient event that would damage agriculture, particularly in the Northern Hemisphere. Because of the cumulative build-up of greenhouse gases in the atmosphere such a cool pause is bound to be followed by resumed heating, consistent with IPCC projections.

The growth in the cold water region south of Greenland, heralding a possible collapse of the Atlantic Mid-Ocean Circulation. Author provided

Humanity’s release of greenhouse gases is unprecedented in speed and scale. But if we look far enough back in time we can get some clues as to what to expect. Around 56 million years ago, Earth experienced warming by 5-8℃ lasting several millennia, after a sudden release of methane-triggered feedbacks that caused the CO₂ level rise to around 1,800ppm.

Yet even that sudden rise of CO₂ levels was lower by a large factor than the current CO₂ rise rate of 2-3ppm per year. At this rate, unprecedented in Earth’s recorded history of the past 65 million years (with the exception of the consequences of asteroid impacts), the climate may be entering truly uncharted territory.

Andrew Glikson 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.

Icebergs breaking off Antarctica, even massive ones, do not typically concern glaciologists. But the impending birth of a new massive iceberg could be more than business as usual for the frozen continent.

The Larsen C ice shelf, the fourth-largest in Antarctica, has attracted worldwide attention in the lead-up to calving an iceberg one-tenth of its area – or about half the area of greater Melbourne. It is still difficult to predict exactly when it will break free.

But it’s not the size of the iceberg that should be getting attention. Icebergs calve all the time, including the occasional very large one, with nothing to worry about. Icebergs have only a tiny direct effect on sea level.

The calving itself will simply be the birth of another big iceberg. But there is valid concern among scientists that the entire Larsen C ice shelf could become unstable, and eventually break up entirely, with knock-on effects that could take decades to play out.

Ice shelves essentially act as corks in a bottle. Glaciers flow from land towards the sea, and their ice is eventually absorbed into the ice shelf. Removal of the ice shelf causes glaciers to flow faster, increasing the rate at which ice moves from the land into the sea. This has a much larger effect on sea level than iceberg calving does.

While the prediction that Larsen C could become unstable is based partly on physics, it is also based on observations. Using aerial and satellite images, scientists have been able to track very similar ice shelves in the past, some of which have been seen to retreat and collapse.

The death of an ice shelf

The most dramatic ice shelf collapse observed so far is that of Larsen C’s neighbour to the north – the imaginatively named Larsen B. Over the course of just six weeks in 2002 the entire ice shelf splintered into dozens of icebergs. Almost immediately afterwards, the glaciers feeding into it sped up by two to six times. Those glaciers continue to flow faster to this day.

Satellite photo series of Larsen B Ice Shelf collapse from January 2002 to April 2002. NASA

In our new study, published in Earth and Planetary Science Letters, we turn the clock back even further to look at the Wordie ice shelf, on the west coast of the southern Antarctic Peninsula, which began to retreat in the 1960s and eventually disappeared in January 2017.

Over the past 20 years, observations have shown that the main glacier feeding into the Wordie ice shelf, the Fleming Glacier, has sped up and thinned. Compared with the glaciers feeding Larsen B and C, Fleming Glacier is massive: 80km long, 12km wide, and 600m thick at its front.

Locations of the Larsen C Ice Shelf and the Wordie Ice Shelf-Fleming Glacier system with ice front positions from 1947 to 2016. Author provided

We used historic aerial photographs from 1966 to create an elevation map of the Fleming Glacier, and compared it to elevation measurements from 2002 to 2015. Between 1966 and 2015 the Fleming Glacier thinned by at least 100m near the front. The thinning rate, which is the elevation change rate, rapidly increased: the thinning rate after 2008 is more than twice that during 2002 to 2008, and four times the average rates from 1966 to 2008.

Ice thinning rate of the Fleming Glacier region during (a) 2002-2008 and (b) 2008-2015. Author provided

Ice flow speeds have also increased by more than 400m per year at the front since 2008. This is the largest speed change in recent years of any glacier in Antarctica. These changes all point to ice shelf collapse as the cause.

We estimate the total glacier ice volume lost from all glaciers that feed the Wordie is 179 cubic kilometres since 1966, or 319 times the volume of Sydney Harbour. The weight of this ice moving off the land and into the ocean has caused the bedrock beneath the glaciers to lift by more than 50mm.

Other research has suggested this lift could have acted to slow the glacier’s retreat, but it’s clear that the bedrock deformation has not stopped the ice movement speeding up. It seems the Fleming Glacier has a long way to go before it will return to a new stable state (in which snowfall feeding the glacier equals the ice flowing into the oceans).

Fifty years after the Wordie Ice Shelf began to collapse, the major feeding glaciers continue to thin and flow faster than before.

We can’t yet predict the full consequences of the new iceberg calving from Larsen C. But if the ice shelf does begin to retreat or collapse, history tells us it is very possible that its glaciers will flow faster – making yet more sea level rise inevitable.

Chen Zhao is a PhD student from the School of Land and Food, University of Tasmania. She receives funding from the Australian Government Research Training Program.

Christopher Watson receives funding from the Australian Research Council and the Department of Environment.

Matt King receives funding from the Australian Research Council and the Department of Environment.

This quenda seems to have been a victim of land clearing. Colin Leonhardt/Birdseyeviewphotography.com.au, Author provided

Tens of millions of wild animals are killed each year by land clearing across Australia, according to our research on the harm done to animals when native vegetation is removed for agricultural, urban and industrial development.

As my colleague Nahiid Stephens and I point out in our study, this harm to animals is largely invisible, unlike the obvious effects of clearing on trees and other plants. But just because something is invisible, that does not mean it should be ignored.

We argue that reforms are necessary to ensure that decision-makers take wild animals’ welfare into account when assessing development proposals and land clearing applications.

How does land clearing harm animals?

Land clearing harms animals in two basic ways. First, they may be killed or injured when native vegetation is removed, typically through the use of earth-moving machinery. For example, animals may suffer traumatic injuries or be smothered when vegetation is cut or soil and debris are shifted.

Second, the removal of native vegetation puts animals in harm’s way. Those that survive the clearing process will be left in an environment that is typically hostile, unfamiliar or unsuitable. Animals are likely to find themselves in landscapes that are devoid of food and shelter but filled with predators, disease, and increased aggression from members of their own species as they struggle to make a living.

Land clearing causes animals to die in ways that are physically painful and psychologically distressing. Animals will also suffer physical injuries and other pathological conditions that may persist for days or months as they try to survive in cleared areas or other environments to which they are displaced.

Many reptiles and mammals are territorial or have small home ranges, and thus have strong associations with small areas of habitat. Koalas in urban areas, for example, tend to rely on particular food trees. Likewise, lizards and snakes often rely on particular microhabitat features such as logs, rocks, and leaf litter to provide the combination of temperature and humidity that they need to survive.

Laws are not protecting animals

Land clearing remains a fundamental pressure on the Australian environment. While the regulatory frameworks for land clearing vary greatly across the Australian states and territories, the principal statutes that govern native vegetation clearance in most jurisdictions typically contain some sort of express recognition of the harm that land clearing causes, such as the loss or fragmentation of habitat, land degradation, and salinity.

Habitat lost: land cleared for the now-discontinued Perth Freight Link road project. Colin Leonhardt/Birdseyeviewphotography.com.au, Author provided

Yet these regulations are uniformly silent on the issue of how land clearing harms animals. No state or territory has developed a clear framework to evaluate this harm, let alone minimise it in future development proposals.

This failure to recognise animal welfare as a significant issue for decision-making about land clearing is troubling, especially given the scale of current land clearing. In Queensland, for example, an estimated 296,000 hectares of woody vegetation was cleared in 2014-15, nearly all of which was for the purpose of converting native vegetation to pasture. In our study we estimate that, on the basis of previous studies and current estimates of clearing rates, land clearing in Queensland and New South Wales combined kills more than 50 million birds, mammals and reptiles each year.

What reforms are necessary?

We suggest that two basic reforms are required. First, state and territory parliaments should amend the laws that govern environmental impact assessments and native vegetation clearance, to require decision-makers to take animal welfare into account when assessing land clearing applications.

Second, we urgently need accurate ways to evaluate the harm that proposed clearing actions may cause to individual animals. Animal welfare is broadly recognised as an important social concern, so it makes sense that in a situation where we know animals are being harmed, we should take steps to measure and prevent that harm.

The basic aim of any reform should be to ensure that the harm that land clearing causes to individual wild animals is appropriately considered in all forms of environmental decision-making and that such evaluations are based on clear and objective criteria for animal welfare.

At a minimum, those who apply to clear native vegetation should be required to provide an estimate of the number and type of native animals that will be killed by the proposed land clearing. This would ensure that all parties – applicants, decision-makers, and the community – understand the harm that the clearing would cause. These estimates could be made by using population density information for species that are likely to be affected – an approach that has been already been used.

We also need to revise our perceptions about the usefulness and necessity of land clearing in Australia. A better idea of what is “acceptable” would include not only the environmental costs of clearing an area of native vegetation, but also the individual suffering that animals will experience.

Issues of causation and responsibility are critical here. While it’s unlikely that someone who wants to clear land actually wants native animals to suffer, such suffering will nevertheless be an inevitable consequence. The relevant question is not whether animals will be killed and harmed when land is cleared, but how much of that harm will occur, how severe it will be, and whether it ought to be avoided.

If such harm is deemed necessary – based on an accepted system for weighing the potential benefits and harms – the next question is how the harm to animals can be minimised by, for example, keeping the amount of vegetation to be cleared to a minimum.

Hugh Finn 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.

AAP/Black Inc Books

Melbourne-born author Anna Krien’s latest Quarterly Essay explores the debates on climate change policy in Australia and the ecological effects of not acting.

She interviewed farmers, scientists, Indigenous groups, and activists from Bowen to Port Augusta. She says climate change denialism has transformed into “climate change nihilism”.

Krien says the Finkel review provides another opportunity in a long line of proposals to take up the challenge of legislating clean energy. “We just need to get that foot in the door. The door has been flapping in the wind for the past decade.”

On a current frontline battle – the planned Adani Carmichael coalmine – she found the people who would be affected were being ignored and blindsided.

Meanwhile, the potential for exploitation of local Indigenous peoples through “opaque” native title legislation was high. “Outsiders are not meant to understand it and to tell you the truth you get the sense that insiders aren’t meant to understand it either.”

Michelle Grattan 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.

Earth’s last intact wilderness areas are being rapidly destroyed. More than 5 million square km of wilderness (around 10% of the total area) have been lost in the past two decades. If this continues, the consequences for both people and nature will be catastrophic.

Predominantly free of human activity, especially industrial-scale activities, large wilderness areas host a huge range of environmental values, including endangered species and ecosystems, and critical functions such as storing carbon and providing fresh water. Many indigenous people and local communities, who are often politically and economically marginalised, depend on wilderness areas and have deep cultural connections to them.

Yet despite being important and highly threatened, wilderness areas have been almost completely ignored in international environmental policy. Immediate proactive action is required to save them. The question is where such action could come from.

In a paper published in Conservation Biology, we argue that the United Nations’ World Heritage Convention should expand the amount of wilderness included in its list of Natural World Heritage Sites (NWHS).

Wilderness areas are underrepresented among the 203 sites currently on the list. The World Heritage Committee’s meeting in Poland this week offers a good opportunity to redress the balance.

Whither wilderness?

The World Heritage Convention was adopted in 1972 by UNESCO (the United Nations Educational, Scientific and Cultural Organization) to conserve the world’s most valuable natural and cultural sites – places of exceptional importance to all of humanity and future generations. Each one is unique and irreplaceable. Currently, 193 countries (almost the entire world) are parties to the convention, which has inscribed 203 natural sites around the world.

World Heritage Status is granted to places with “Outstanding Universal Value”, which is defined based on three pillars. First, a site must meet one of the four criteria for listing as natural World Heritage (aesthetic value, geological value, biological processes, and biodiversity conservation). Second, a site must have “integrity” and “intactness” of its values (in other words, it must be in excellent condition). Finally, a site must be officially protected by the national or subnational government under whose jurisdiction it falls.

Wilderness areas can be associated with all four of the natural criteria, as well as the integrity and intactness requirements. What’s more, a wilderness by definition cannot be recreated once it is lost. The argument for protecting wilderness areas by adding them to the NWHS list is therefore compelling.

We created the most up-to-date maps of terrestrial wilderness using recent maps of human pressure and assessed the World Heritage Convention’s current coverage of wilderness areas. We found that some 777,000 square km (around 2% of the total) are already protected in 52 Natural World Heritage Sites.

Very little of the world’s wilderness (green) is within natural World Heritage Sites (pink). Author provided

For example, more than 90% of the World Heritage-listed Purnululu National Park in the Kimberley region of Western Australia can be defined as a wilderness area. Similarly, the Okavango Delta in Botswana features more than 18,000 square km of wilderness, containing many of the world’s most endangered large mammals.

Wilderness boosts heritage value

In these cases, wilderness areas are likely contributing to the Oustanding Universal Value of of these World Heritage Areas – which as explained above is a key consideration in how they are managed and protected.

One way to strengthen this protection further would be to redraw the boundaries of natural World Heritage Areas to include more wilderness. This would help to preserve the conditions that allow ecosystems and other heritage values to thrive.

Our study identified broad gaps in wilderness coverage by the World Heritage Convention. Some places are already protected by national governments and could therefore be added to UNESCO’s list, such as the Hukaung Valley Tiger Reserve in Myanmar, which contains 4,000 square km of wilderness, and the Eduardo Avaroa Andean Fauna Reserve in Bolivia, which has 9,000 square km.

The places we have identified, and others, could potentially be designated as new Natural World Heritage Sites if they meet the other strict criteria for Outstanding Universal Values and integrity.

The World Heritage Convention could better achieve its objectives and make a substantial contribution to the conservation of wilderness areas by doing these four things:

1. formally acknowledge the Outstanding Universal Values of wilderness areas

2. strengthen the current protection of wilderness within NWHS

3. expand or reconfigure current NWHS to include more wilderness, and

4. designate new NWHS in wilderness areas.

It’s up to national governments to submit sites for inscription as NWHS, and we urge them to consider wilderness when doing so. This will strengthen their applications, and provide wilderness areas with the extra protection they need.

The UNESCO World Heritage Committee’s meeting in Poland this week will consider two sites with significant wilderness areas for World Heritage status: Qinghai Hoh Xil Nature Reserve in China and Los Alerces National Park in Argentina. We urge the committee to approve these sites, and use this to spur further opportunities to raise the profile of wilderness conservation worldwide. It is an obvious win-win.

The clock is ticking fast for our last wilderness areas and the biodiversity they protect. Immediate action is needed.

James Allan receives a stipend from The Australian Research Council

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

“Sustainability” is, ironically, a growth industry. Ever since the term “sustainable development” burst onto the scene in 1987 with the release of Our Common Future (also known as the Brundtland report), there has been a dizzying increase in rhetoric about humanity’s relationship with our planet’s resources. Glossy reports - often featuring blonde children in front of solar panels or wind turbines - abound, and are slapped down on desks as proof of responsibility and stewardship.

Every few years a new term is thrown into the mix - usually preceded by adjectives like “participatory” or “community-led”. The fashionability of “resilience” as a mot du jour seems to have peaked, while more recently the “circular economy” has become the trendy term to put on grant applications, conference notices and journal special editions. Over time journals are established, careers are built, and library shelves groan.

Meanwhile, the planetary “overshoot”, to borrow the title of a terrifying 1980 book, goes on - exemplified by rising concentrations of atmospheric carbon dioxide, warmer oceans, Arctic melting, and other signs of the times.

With all this ink being spilled (or, more sustainably, electrons being pressed into service), is there anything new to say about sustainability? My colleagues and I think so.

Three of us (lead author Ulrike Ehgartner, second author Patrick Gould and myself, recently published an article called “On the obsolescence of human beings in sustainable development”.

In it we explore the big questions of sustainability, drawing on some of the work of an unjustly obscure Austrian political philosopher called Gunther Anders.

Who was Günther Anders?

He was born Günther Siegmund Stern in 1902. While he was working as a journalist in Berlin, an editor wanted to reduce the number of Jewish-sounding bylines. Stern plumped for “Anders” (meaning “other” or “different”) and used that nom de plume for the rest of his life.

Anders knew lots of the big philosophical names of the day. He studied under Edmund Husserl and Martin Heidegger. He was briefly married to Hannah Arendt, and Walter Benjamin was a cousin.

But despite his stellar list of friends and family, Anders himself was not well known. Harold Marcuse points out that the name “Stern” was pretty apt, writing:

His unsparingly critical pessimism may explain why his pathbreaking works have seldom sparked sustained public discussion.

While Hiroshima and the nuclear threat were the most obvious influences on Anders’ writing, he was also crucially influenced by the events at Auschwitz, the Vietnam War, and his periods in exile in France and the United States. But why should we care, and how can his ideas be applied to modern-day ideas about sustainability?

Space precludes a blow-by-blow account of what my colleagues and I wrote, but two ideas are worth exploring: the “Promethean gap” and “apocalyptic blindness”.

Anders suggested that the societal changes wrought by the industrial age – chief among them the division of labour – opened a gap between individuals’ capability to produce machines, and their capability to imagine and deal with the consequences.

So, riffing on the Greek myth of Prometheus (the chap who stole fire from Mount Olympus and gave it to humans), Anders proposed the existence of a “Promethean gap” which manifests in academic and scientific thinking and leads to the extensive trivialisation of societal issues.

The second idea is that of “apocalyptic blindness” – which is, according to Anders, the mindset of humans in the Age of the Third Industrial Revolution. This, as we write in our paper:

…determines a notion of time and future that renders human beings incapable of facing the possibility of a bad end to their history. The belief in progress, persistently ingrained since the Industrial Revolution, causes the incapability of humans to understand that their existence is threatened, and that this could lead to the end of their history.

Put simply, we don’t want to look an apocalypse in the eye, even if it’s heading straight towards us.

The climate connection

“So what?” you might ask. Why listen to yet another obscure philosopher railing about technology, in the vein of Lewis Mumford and Jacques Ellul? But I think a passing knowledge of Anders and his work reminds us of several important things.

This is nothing new. Recently, the very notion of ‘progress’ has come under renewed assault, with books questioning our assumptions about it. This is not new of course - in a 1967 short story collection about life at the United Nations, Shirley Hazzard had written:

About this development process there appeared to be no half-measures: once a country had admitted its backwardness, it could hope for no quarter in the matter of improvement. It could not accept a box of pills without accepting, in principle, an atomic reactor. Progress was a draught that must be drained to the last bitter drop.

The time - if ever there was one - for tinkering around the edges is over. We need to take stronger action than simply pursuing our feelgood preoccupation with sustainability.

This begs the question of who is supposed to shift us from the current course (or rather, multiple collision courses. That’s a difficult one to answer.

The hope that techno-fixes (including 100% renewable energy) will sort out our problems is a dangerous delusion (please note, I’m not against 100% renewables - I’m just saying that green energy is “necessary but not sufficient” for repairing the planet.

Similarly, the “circular economy” has a rather circular feeling to it – in the sense that we’ve seen all this before. It seems (to me anyway) to be the last gasp of the “ecological modernist” belief that with a bit more efficiency, everything can simply keep on progressing.

Our problems go far deeper. We are going to need a rapid and fundamental shift in our values, habits, behaviours, and outlooks. Put in Anders’ terms, we need to stop being blind to the possibility of apocalypse. But then again, people have been saying that for a century or more.

Red-eared sliders were once popular pets but are currently banned in Australia. These turtles are still regularly found in the wild and being kept as illegal pets. Pablo Garcia-Diaz, Author provided

A taste for owning exotic animals can be addictive – the more flamboyant the better. Earlier this month border security agents found 50 live turtles and lizards smuggled in Lego boxes sent from Indonesia. In April customs officials found a parcel marked “2 pair shoes” that turned out to contain venomous vipers, tarantulas and scorpions.

According to the Animals Medicines Australia 2016 survey some two-thirds of Australian households have pets – more than 24 million animals in total. Not surprisingly, dogs and cats are the most popular (38% and 29% of households, respectively), whereas aquarium fish and birds rank somewhere in the middle (both 12%), and reptiles and less common mammals are kept in some households (both less than 5%).

The federal government largely legislates the owning of exotic pets. The law defines “exotic” as “animals that do not occur naturally in the wild in Australia” – which actually includes dogs and cats. However “domesticated mammals”, which also covers cows, sheep and other farm animals, are generally legal to buy and own. Commercial trade in exotic reptiles and amphibians, on the other hand, has been banned since 1999.

Whether an exotic animal is kept legally or not, some will find their way to the Australian wild through escape or release, posing a potential pest risk. There are some simple things governments and pet owners can do to improve the way this risk is handled, to keep animals and humans safe.

We don’t really know how many exotics are in Australia

Most local councils only require dogs (and sometimes cats) to be registered by their owners. Other pets, whether exotic or native, do not need to be registered. Indeed an owner of an exotic animal is not required to report or register the animal in any way. This means there are very little reliable data and it’s difficult to say how many exotic pets are kept in Australia.

We highlight two cases from our own research: birds and reptiles.

Bird-keeping is common in Australia, particularly of parrots and finches. More than half the bird species traded are exotic and mostly originate in South America, Africa and Asia. Rose-ringed Parakeets are one of the most commonly kept exotic pet bird, and the most frequently reported as having escaped. They are seen as a potential threat because they are a serious agricultural pest in its’ native and exotic distribution, and have a very high risk of establishing in Australia.

The Rose-ringed parakeet is a common pet in Australia and presents a potential biosecurity risk. Dick Danies/Wikimedia

Reptiles – generally skinks, turtles and dragons – are less popular pets than birds. Nonetheless, judging from the posts on public trading webpages, a variety of native reptile species are kept and traded by hobbyists, also including crocodiles and snakes.

Unfortunately, little is known about native reptile trading in Australia and further research is needed. And while native reptiles can be kept legally, illegal exotic reptiles are a serious problem. In a previous article for The Conversation, we reported that 28 alien reptile species were illegally kept in Victoria between 1999 and 2012. More than a third were highly venomous snakes, posing a real risk to human safety.

Responsibly caring for exotic pets

If you own or want to buy an exotic pet, you must be aware of the regulations that apply to you (you can Google “exotic pet regulations” plus the name of your state or territory). Each jurisdiction keeps official lists of those species that may be kept within their borders, with or without a permit. These lists can be found on local government websites or obtained from their relevant departments.

People should also be able to register all of their pets, including exotic ones. Governments need to promote public awareness of the importance of registration (even if it’s not legally required), and ensure the processes are simple, accessible and affordable.

If you lose your exotic pet, it’s important to alert your state or territory biosecurity agency. Each jurisdiction has its own agency, but examples are the Western Australia Department of Agriculture and Food or Agriculture Victoria. If you want to recover your lost pet the best available option is to report your loss to one of the many missing animal websites.

Governments, when facilitating the registration process, will need to establish best practices to collect and analyse information so that the nature and extent of pet ownership may be better known, monitored and managed.

Ultimately, the burden of safe and responsible pet ownership should be shared. While public awareness is crucial, the key to a sustainable pet trade is mutual partnership between pet owner communities and governments. This is particularly important as pet sales and trade shift further to an online environment.

Pablo García-Díaz received funding from the Invasive Animals CRC and the Department of Education and Training (Australian Government). He is currently also affiliated with Landcare Research New Zealand.

Miquel Vall-llosera received funding from the Invasive Animals CRC.

Phill Cassey receives funding from the Australian Research Council.

The Murray-Darling Basin is an incredibly complex ecological system. Mike Russell/Flickr, CC BY-SA

After a long and contentious public debate, in 2012 Australia embarked on a significant and expensive water recovery program to restore the Murray-Darling Basin’s ecosystems.

Despite general agreement that a certain amount of water should be reserved to restore the flagging river system, the argument continues as to whether this should be 2,750 or 3,200 gigalitres (GL) a year, and how these savings can be achieved.

A recent report by the Wentworth Group of Concerned Scientists argues that there is no conclusive evidence, after five years, that the plan is effective. The report’s authors believe that an extra 450GL of water a year needs to be recovered to save the basin.

There is no doubt in our minds that the Murray-Darling river system is in crisis, and the Basin Plan was vitally needed. But while we broadly agree with the Wentworth Group’s report, it’s a mistake to focus on water volume alone.

Without giving equal attention to improving water quality and building critical ecological infrastructure, it’s possible that increasing river flows could actually harm the Basin.

What are we trying to recover?

We don’t really have much information on the state of the basin before industrial development. Most knowledge is more recent, but we do know that from about the 1920s onwards, considerable volumes of water have been removed. Few comprehensive historic records of flora and fauna, let alone water quality, are available.

While knowledge of the state and significance of the ecology of the river systems is scant, there is ample evidence that increased levels of nutrients, salts and, in particular, sediments have adversely affected the wetlands, main channels and associated floodplains.

The records of fish that historically lived in the rivers, billabongs and wetlands also tell a cautionary tale. These wetlands and rivers once teemed with native fish. In 1915, a single scoop of a 10 m seine net would yield more than 100,000 native fish in a single wetland.

There were dozens of species at each site, supporting a burgeoning fishery that was considered inexhaustible.

An example of extreme overfishing of Murray cod in the late 1800s, which caused the first strong declines in the species. Such catches were typical for the period. https://en.wikipedia.org/wiki/Murray_cod

Since that time the basin has been extensively developed. The fishing industry expanded, forests were cleared, dams were built, floodplains were blocked by levies, water began to be diverted for irrigation, the demand for drinking water increased and invasive species were introduced. But somewhere over the past 100 years we crossed a threshold where the system stopped being able to support native fish.

Nowadays, visiting the wetlands that were historically packed with native fish (all of which had huge cultural importance to traditional owners), we find mostly invasive species such as carp, goldfish and weatherloach.

In some places, native species that were once abundant have not been seen in 40 years. The formerly productive commercial fisheries, and the livelihoods they supported, have been shut down.

Our native fish are in trouble, and unless urgent action is taken, many face extinction within decades.

Rebuilding a complex system

The Basin Plan is underpinned by a focus on river volume as the cause of system degradation and subsequent recovery. But the system is much more complex than that. Fluctuating levels of sediments, salts and nutrients drive significant changes, and so regulating river flows – which carry these components from place to place – fundamentally alters the dynamics of main channels and floodplain wetlands.

Over the last century, erosion has filled the rivers in the Murray system with mud. When this water flows into the wetlands, this sediment builds and blocks the light, killing the aquatic plants that support native fish.

Simply increasing the water flow without addressing water quality runs the risk of exacerbating this problem. We therefore argue the first step in river recovery is attending to water quality.

The Murray-Darling Basin Plan has focused very heavily on the amount of water in the system; partly because speaking in terms of volume is easiest to demonstrate and understand. But the paleoecological record reveals that water quality, at least in wetlands, declined well before human use of water changed the river flows.

So if recovering water volume is a critical target, it is equally important that this water is of good quality. Recent experience with blackwater events, in which oxygen levels drop so low that fish suffocate, highlights this need. Even water of the wrong temperature, known as “thermal pollution”, can cause real harm. Winter-temperature water, for example, can prevent fish from breeding if it occurs in summer. Bad water quality will simply not provide good ecological outcomes.

A century of engineering development has fundamentally changed the basins rivers in a way that does not support native fish or the original ecology in general. Even if the recovered water is of high quality, we will need to take other steps to achieve tangible outcomes. Thus we need “complementary measures”, which augment the benefits of increasing river volumes. These include:

• Mitigating thermal and other pollution to ensure the water temperature and overall quality is adequate,
• Building fishways so that fish can navigate dams and weirs,
• Restocking threatened fish species into areas they are no longer found,
• Controlling carp and other non-native species that now dominate our waterways;
• Building fish-friendly irrigation infrastructure such as screens on irrigation pumps or overshot weirs; and
• Improving habitat through resnagging or controlling harmful practices on flood plains.

Another measure to improve the basin’s waterways, the proposal to release a virulent strain of carp herpes, has raised debate over whether it will neatly solve a major environmental and economic problem or create further issues.

If implemented correctly, these complementary measures are just as important as water recovery and improving water quality for meeting the basin plan’s ecological targets.

Repairing a river system such as the Murray-Darling is incredibly complex, and we must broaden our view beyond simply thinking about water volumes. Some of these extra steps can also provide benefits with less cost to the people who live and work with the water. To achieve this we suggest a staged program of recovery that allows the communities who live in the basin more time to adapt to the plan.

Max Finlayson receives funding from the Australian Centre for International Agricultural Research and the Australian Research Council.

Lee Baumgartner works with the Fisheries Research and Development Corporation to investigate the benefits of complementary measures across the basin, including the release of the carp virus.

Peter Gell received funding from ARC to fund previous research into the Murray-Darling Basin. He currently receives funding from the NSW state government for research into wetlands. He is a member of the Greens.

Two papers published today report that neonicotinoids have negative effects on honey bees and wild bees in realistic field experiments. from www.shutterstock.com, CC BY-ND

Some of the world’s most widely used pesticides can be harmful to bees, according to the first large-scale studies aimed at measuring the impact of compounds called neonicotinoids on bees’ health. But the effects vary widely between different compounds and different countries, suggesting that more regional research will be needed to clarify the exact scale of the problem.

Neonicotinoids, which are typically coated onto seeds before planting rather than being sprayed onto crop plants, were developed with the aim of harming only those animals that eat the plants. But they are also found in the pollen and nectar of treated plants, potentially affecting beneficial organisms like bees.

Two papers published today in the journal Science report that neonicotinoids have negative effects on honey bees and wild bees in realistic field experiments. But the results are mixed and far from conclusive.

The concern about neonicotinoids prompted the European Union to impose a temporary moratorium in 2013 on the use of three key pesticides. In contrast, New Zealand’s government has joined with Australia in not imposing a ban. I think our governments have made exactly the right decision at this time.

Study confirms negative effects

One of the studies, led by Nadejda Tsvetkov at York University, Canada, indicates that chronic exposure to neonicotinoids reduces honey bees’ health near Canadian corn fields.

This is consistent with many previous research findings showing that feeding on large amounts of neonicotinoids can be fatal to honey bee workers and queens.

For bees given a smaller dose, their foraging becomes less efficient. They undertake reduced hygienic behaviour in the hive and their immune system seems to be impaired. And their tolerance of other stressors bees experience in their environment, in this case a fungicide, is reduced.

The new Canadian study shows that field-realistic exposure to neonicotinoids can substantially reduce honey bees’ health.

Other results mixed

The other study, led by Ben Woodcock of Britain’s Natural Environment Research Council, describes research done on three different bee species in three different countries. It also attempted to use field-realistic exposure to neonicotinoids. Populations of honey bees, bumble bees and a solitary bee were followed in the United Kingdom, Hungary and Germany.

The team examined two neonicotinoid pesticides, and found a fascinatingly mixed bag of results. Both pesticides resulted in significantly reduced numbers of honey bee eggs being produced in Hungary. But exposure to both pesticides in Germany resulted in significantly more eggs being produced. Neonicotinoids also seemed to result in higher numbers of workers surviving winter in Germany.

In Hungary, fewer worker bees survived winter after exposure to one pesticide, but not the other. Similarly, in the United Kingdom, there were mostly negative but some positive effects of exposure to the different neonicotinoid pesticides.

The take-home message is that different neonicotinoids can have different effects, which can be very specific to the country of use. After reading these results, if I were a grower in Germany, I might start to question the European Union’s temporary moratorium.

Country-specific data needed

These studies highlight the need for data to allow countries like New Zealand and Australia to effectively manage the use of neonicotinoid pesticides. We need to know the effects of neonicotinoids in our specific environmental conditions and in the way we use them.

We also need to know what the effects would be if we took this group of pesticides away. I’ve read reports that growers in the UK have had to revert to broad-spectrum pesticides that are considered worse for the environment and mean they cannot grow certain crops.

In 2013, the Australian government undertook a review of neonicotinoids and the health of honey bees. This concluded that “the introduction of the neonicotinoids has led to an overall reduction in the risks to the agricultural environment from the application of insecticides”.

The review found little scientific evidence to show that the current use of neonicotinoids in Australia causes widespread harm to honey bees. The review stated that “the introduction of the neonicotinoid insecticides has brought a number of benefits, including that they are considerably less toxic to humans (and other mammals) than the organophosphorus and carbamate insecticides they have significantly replaced”.

Bees are up against it

Honey bees in New Zealand have a plethora of known and scientifically demonstrated threats. These include invasive blood-sucking mites, and the deformed wing virus, which has been described as a key contributor to the collapse of bee colonies around the world.

New Zealand’s bees have bacterial pathogens like American foulbrood that results in beekeepers having to burn their bees and hives. Fungal diseases are widespread. We also have management issues with the higher-than-ever numbers of managed hives, which are often managed poorly and often overstocked. These are real and known issues affecting our honey bees now. We have data on these problems that can guide their management.

The new research will doubtless lead to calls from some quarters for Australia and New Zealand to ban neonicotinoid pesticides. I hope that the New Zealand and Australian governments act on studies like those published today, but I would be disappointed if that action was anything other than evidence- and science-based. Let’s gather the data specifically for each country, and then make a decision on whether and how to use these pesticides.

Phil Lester has not received funding from pesticide companies. His work is funded from a number of government sources, including the Royal Society Te Aparangi and the National Science Challenge in New Zealand.

Deloitte Access Economics has valued the Great Barrier Reef at A$56 billion, with an economic contribution of A$6.4 billion per year. Yet this figure grossly underestimates the value of the reef, as it mainly focuses on tourism and the reef’s role as an Australian icon.

When you include aspects of the reef that the report excludes, such as the ecosystem services provided by coral reefs, you find that the reef is priceless.

Putting a price on the Great Barrier Reef buys into the notion that a cost-benefit analysis is the right way to make decisions on policies and projects that may affect the reef. For example, the environmental cost of the extension to the Abbot Point coal terminal can be compared to any economic benefits.

But as the reef is both priceless and irreplaceable, this is the wrong approach. Instead, the precautionary principle should be used to make decisions regarding the reef. Policies and projects that may damage the reef cannot go ahead.

How do you value the Great Barrier Reef?

The Deloitte report uses what’s known as a “contingent valuation” approach. This is a survey-based methodology, and is commonly used to measure the value of non-market environmental assets such as endangered species and national parks – as well as to calculate the impact of events such as oil spills.

In valuing the reef, surveys were used to elicit people’s willingness to pay for it, such as through a tax or levy. This was found to be A$67.60 per person per year. The report also uses the travel-cost method, which estimates willingness to pay for the Great Barrier Reef, based on the time and money that people spend to visit it. Again, this is commonly used in environmental economics to value national parks and the recreational value of local lakes.

Of course, all methods of valuing environmental assets have limitations. For example, it is difficult to make sure that respondents are stating realistic amounts in their willingness to pay. Respondents may act strategically if they think they really will be slugged with a Great Barrier Reef levy. They may conflate this environmental issue with all environmental issues.

But more importantly, the methodology in the report leaves out the most important non-market value that the reef provides, which are called ecosystem services. For example, coral reefs provide storm protection and erosion protection, and they are the nurseries for 25% of all marine animals which themselves have commercial and existence value.

The Deloitte report even cites (but does not reference) a 2014 study that values the ecosystem services provided by coral reefs at US$352,249 per hectare per year. The Great Barrier Reef Marine Park covers 35 million hectares with 2,900 individual reefs of varying sizes. This means the ecosystem services it provides are worth trillions of dollars per year.

That is, it is essentially priceless.

The problem with putting a value on the Reef

Valuing the environment at all is contentious in economics. Valuation is performed so that all impacts from, say, a new development, can be expressed in a common metric – in this case dollars. This allows a cost-benefit analysis to be performed.

But putting a price on the Great Barrier Reef hides the fact that it is irreplaceable, and as such its value is not commensurate with the values of other assets. For instance, using Deloitte’s figure, The Australian newspaper compared the reef to the value of 12 Sydney Opera Houses. But while they are both icons, the Opera House can be rebuilt. The Great Barrier Reef cannot. Any loss is irreversible.

When environmental assets are irreplaceable and their loss irreversible, a more appropriate decision-making framework is the Precautionary Principle.

The Precautionary Principle suggests that when there is uncertainty regarding the impacts of a new development on an environmental asset, decision makers should be cautious and minimise the maximum loss. For example, if it is even remotely possible that the extension to the Abbot Point coal terminal could lead to massive destruction of the reef, then precaution suggests that it shouldn’t go ahead.

Assigning a value to the reef might still be appropriate under the Precautionary Principle, to estimate the maximum loss. But it would require the pricing of all values and especially ecosystem services.

While the Precautionary Principle has been much maligned due to its perceived bias against development, it is a key element of the definition of Ecologically Sustainable Development in Australia’s Environment Protection and Biodiversity Conservation Act 1999.

For a priceless asset like the Great Barrier Reef, it is perhaps better to leave it as “priceless” and to act accordingly. After all, if the Precautionary Principle is ever going to be used when assessing Ecologically Sustainable Development, in contrast with cost-benefit analysis and valuations, it is surely for our main environmental icon.

Ultimately, the protection and prioritisation of the Great Barrier Reef is a political issue that requires political will, and not one that can be solved by pricing and economics.

Neil Perry 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.

Adélie penguin at the Mt Siple breeding colony, West Antarctica. Jasmine Lee, Author provided

When you think of Antarctica, you probably picture vast, continuous ice sheets and glaciers, with maybe a penguin or two thrown in. Yet most Antarctic plants and animals live in the permanently ice-free areas that cover about 1% of the continent. Our new research predicts that these areas could grow by a quarter during this century, with mixed prospects for the species that currently live there.

Besides everyone’s favourite Emperor and Adélie penguins, terrestrial Antarctic species also include beautiful mosses, lichens, two types of flowering plants, and a suite of hardy invertebrates such as nematodes, springtails, rotifers and tardigrades, many of which are found nowhere else on Earth. Tardigrades – tiny creatures sometimes nicknamed “waterbears” – are so tough they can survive in space.

Antarctica’s ice-free areas are currently limited to a scattering of rocky outcrops along the coastline, or cliff faces, or the tops of mountain ranges. They form small patches of suitable habitat in a huge sea of ice, much like islands.

As a result, the plants and animals that live there are often isolated from each other. But as Antarctica’s climate warms, we expect ice-free areas to get bigger and eventually start joining up. This would create more habitat for native species, but also new opportunities for non-native species to spread.

Our study, published today in Nature, forecasts that climate change will expand Antarctica’s ice-free areas over the course of this century. Under the most severe scenario that we modelled (which is also the one on which the globe is currently tracking), more than 17,000 square km of new ice-free area could emerge across the continent by 2100.

This would increase the current total ice-free area by nearly a quarter. The majority of this new ice-free land will be on the Antarctic Peninsula, which could have three times as much ice-free area as it does today.

Projected Antarctic ice melt this century. Lee et al. (2017) Nature Brave new world

As the ice-free areas expand, the distances between them will decrease, giving plants and animals more opportunity to spread through the landscape. On the Antarctic Peninsula, which has already warmed more than anywhere else in Antarctica, many of the ice-free patches will expand so much that they will start joining together.

Will this increase in habitat availability benefit the plants and animals that live there? It will definitely provide new opportunities for some native plants and animals to expand their range and colonise new areas. The warming climate may also give a boost to species that are currently hampered by the lack of warmth, nutrients and water. Some Antarctic mosses, for example, are expected to grow faster as temperatures rise, and Antarctica’s two flowering plant species are already expanding southward.

However, the potential benefits seem likely to be outweighed by the negatives. The joining-up of habitat patches could allow species that have been isolated for much of their evolutionary past to meet suddenly. If the newcomers to a particular area outcompete the native species, then it may lead to localised extinctions. Over the coming centuries this could lead to the loss of many plants and animals, and the homogenisation of Antarctica’s ecosystems.

Antarctic aliens

An even bigger concern is that Antarctica’s great thaw could provide new opportunities for species to invade. Antarctica’s best bulwark against non-native species is its harsh climate and extreme weather, to which native Antarctic species have spent many thousands of years adapting.

A native Frisea springtail. Melissa Houghton

We already know that many plants and invertebrates are reaching Antarctica, most often in food or cargo shipments. As the climate warms, some of these non-native species may be able to establish themselves on the Antarctic Peninsula, and the increasing connectivity will allow them to easily move through the landscape. Many of these animals and plants may become invasive, competing with the native species for space and resources.

We don’t know how Antarctica’s species will cope with the increasing competition. But if the sub-Antarctic islands provide any indication, the outlook is depressing. Australia’s World Heritage-listed Macquarie Island, for example, was severely impacted by invasive cats, rats, rabbits and mice (although it has since been declared free of these pests after an intensive eradication effort).

Several non-native species have already come to Antarctica, including the invasive annual meadowgrass Poa annua (a common weed around the world), which has colonised newly ice-free areas left behind by retreating glaciers. It is thought to outcompete Antarctica’s native plants, although we don’t yet know what the impact will be on animals.

Invasive meadowgrass on Macquarie Island. Laura Williams

Humans – both scientists and tourists – are key transporters of non-native species to the continent, and tourist numbers continue to grow (almost 37,000 visited in the 2016-17 summer).

Biosecurity is paramount for the ongoing protection of Antarctica. If bags, shoes, clothes and field equipment are not properly cleaned and inspected before arriving on the continent, then non-native seeds, microbes and insects could be transported to Antarctica and begin to spread.

We call for protection of ice-free areas that will remain intact in a changing climate, and for the Antarctic scientific and tourism communities to pinpoint key areas where greater biosecurity and monitoring for invasive species may be needed.

Jasmine Lee is also affiliated with CSIRO. She receives funding from from the Holsworth Wildlife Research Endowment - Equity Trustees Charitable Foundation, the Ecological Society of Australia, and the Australian Antarctic Science Program (Project 4297).

Justine Shaw receives funding from Australian Government’s National Environmental Science Programme through the Threatened Species Recovery Hub

Richard Fuller receives funding from the Australian Research Council.

Over the past decade we have seen a substantial increase in our scientific understanding of how climate change affects extreme rainfall events. Not only do our climate models suggest that heavy rainfall events will intensify as the atmosphere warms, but we have also seen these projections start to become reality, with observed increases in rainfall intensity in two-thirds of the places covered by our global database.

Given this, we might expect that the risk of floods should be increasing globally as well. When it comes to global flood damage, the economic losses increased from roughly US$7 billion per year in the 1980s to US$24 billion per year in 2001-11 (adjusted for inflation).

It would be natural to conclude that at least some of this should be attributable to climate change. However, we know that our global population is increasing rapidly and that more people now live in flood-prone areas, particularly in developing countries. Our assets are also becoming more valuable – one only needs to look at rising Australian house prices to see that the values of homes at risk of flooding would be much greater now than they used to be in decades past.

So how much of this change in flood risk is really attributable to the observed changes in extreme rainfall? This is where the story gets much more complicated, with our new research showing that this question is still a long way from being answered.

Are floods on the rise?

To understand whether flood risk is changing – even after accounting for changes in population or asset value – we looked at measurements of the highest water flows at a given location for each year of record.

This sort of data is easy to collect, and as such we have reasonably reliable records to study. There are more than 9,000 streamflow gauges around the world, some of which have been collecting data for more than a century. We can thus determine when and how often each location has experienced particularly high volumes of water flow (called “large streamflow events”), and work out whether its flood frequency has changed.

A streamflow gauging station in Scotland. Jim Barton/Wikimedia Commons, CC BY-SA

We found that many more locations have experienced a decrease in large streamflow events than have experienced an increase. These decreases are particularly evident in tropical, arid, and humid snowy climate regions, whereas locations with increasing trends were more prevalent in temperate regions.

To understand our findings, we must first look closely at the factors that could alter the frequency and magnitude of these large streamflow events. These factors are many and varied, and not all of them are related directly to climate. For example, land-use changes, regulated water releases (through dam operations), and the construction of channels or flood levées could all influence streamflow measurements.

We looked into this further by focusing on water catchments that do not have large upstream dams, and have not experienced large changes in forest cover that would alter water runoff patterns. Interestingly, this barely changed our results – we still found more locations with decreasing trends than increasing trends.

The Australian Bureau of Meteorology and similar agencies worldwide have also gone to great lengths to assemble “reference hydrological stations”, in catchments that have experienced relatively limited human change. Studies that used these sorts of stations in Australia, North America and Europe are all still consistent with our findings – namely that most stations show either limited changes or decreases in large streamflow events, depending on their location.

What can we say about future flood risk?

So what about the apparent contradiction between the observed increases in extreme rainfall and the observed decreases in large streamflow events? As noted above, our results don’t seem to be heavily influenced by changes in land use, so this is unlikely to be the primary explanation.

An alternative explanation is that, perhaps counterintuitively, extreme rainfall is not the only cause of floods. If one considers the 2010-11 floods in Queensland, these happened because of heavy rainfall in December and January, but an important part of the picture is that the catchments were already “primed” for flooding by a very wet spring.

Perhaps the way in which catchments are primed for floods is changing. This would make sense, because climate change also can cause higher potential moisture loss from soils and plants, and reductions in average annual rainfall in many parts of the world, such as has been projected for large parts of Australia.

This could mean that catchments in many parts of the world are getting drier on average, which might mean that extreme rainfall events, when they do arrive, are less likely to trigger floods. But testing this hypothesis is difficult, so the jury is still out on whether this can explain our findings.

Despite these uncertainties, we can be confident that the impacts of climate change on flooding will be much more nuanced than is commonly appreciated, with decreases in some places and increases in others.

Your own flood risk will probably be determined by your local geography. If you live in a low-lying catchment close to the ocean (and therefore affected by sea level rise), you’re probably at increased risk. If you’re in a small urban catchment that is sensitive to short sharp storms, there is emerging evidence that you may be at increased risk too. But for larger rural catchments, or places where floods are generally caused by snow melt, the outcome is far harder to predict and certain locations may see a decrease in flooding.

All of this means that a one-size-fits-all approach is unlikely to be suitable if we are to allocate our resources wisely in adjusting to future flood risk. We must also think about the effects of climate change in a broader context that includes changes to land-use planning, investment in flood protection infrastructure, flood insurance, early warning systems, and so on.

Only by taking a holistic view, informed by the best available science, can we truly minimise risk and maximise our resilience to future floods.

Seth Westra receives funding from the Australian Research Council, the Water Corporation of Western Australia and the Goyder Institute.

Hong Xuan Do 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.

Over the past two years The Conversation has published my analyses on a range of topics related to climate change and politics, including climate denial in the Liberal Party, 25-year-old cabinet papers (not once but twice), coal industry PR campaigns and much else besides. Finally comes a topic I can cheerfully say I know nothing about (at first hand, at least): raising children.

Apologies for oversharing, but I had a vasectomy in 2004. The columnist Andrew Bolt spotted this, via an article in Britain’s Daily Mail which clearly stated that I was the one who had been under the knife. Bolt claimed that my wife had “sterilised herself”. (She does a lot of yoga, but she’s not that flexible. We have pointed this out but Bolt has kept at it, repeating the claim almost six years later).

Despite what the Daily Mail article says (and what is within the quotes was never said), our decision not to have kids wasn’t based on concern for what our hypothetical children would do to the planet, but rather what the planet would do to them. My wife copped some online abuse, and I was once disinvited to appear on the BBC after explaining my actual position.

I first switched on to climate change in about 1989, and have become convinced that the second half of the 21st century will probably make the first half of the 20th look like a golden age of peace and love. There have been 30 years of promises and pledges, protocols and agreements, while atmospheric greenhouse gas levels have climbed remorselessly due to humanity’s emissions. I suspect that the reported recent flatlining in emissions growth could well turn out to be as illusory as the so-called global warming “hiatus”.

Writing recently in the Sydney Morning Herald, climate scientist Sophie Lewis eloquently asked:

Should we have children? And if we do, how do we raise them in a world of change and inequity? Can I reconcile my care and concern for the future with such an active and deliberate pursuit of a child? Put simply, I can’t.

While I would never presume to tell anyone what to do with their genitals, I must confess my personal amazement that climate activists who do have children - and who I know have read the same scientific research as me and drawn the same conclusions – aren’t freaking out more. (Perhaps they are just very tired.)

As the Manic Street Preachers sagely warned, our children will have to tolerate whatever we do, and more besides.

Be prepared?

So how do we prepare tomorrow’s adults for the world bequeathed to them by the adults of yesterday and today? Even the mainstream media is beginning to ask this question.

Some studies say young people don’t care enough about climate change; others claim they do. The Australian picture seems to be mixed.

As the environmental writer Michael McCarthy has lamented:

A new edition of the Oxford Junior Dictionary was published in 2007 with a substantial group of words relating to nature – more than 50 – excised: they included acorn, adder, ash, beech, bluebell, buttercup, catkin, conker, cowslip and dandelion. Their replacements included terms from the digital world such as analogue, blog, broadband, bullet-point, celebrity, chatroom, cut-and-paste, MP3 player and voicemail.

Might we be more adaptive than we think? The social demographers Wolfgang Lutz and Raya Muttarak, in their snappily titled paper Forecasting societies’ adaptive capacities through a demographic metabolism model, think so, describing how “the changing educational composition of future populations” might help societies adapt to climate change.

But not everyone thinks our brains will get us out of the mess that they and our opposable thumbs have got us into. As an editor at the Daily Climate pointed out:

A substantial portion of the human population lives on coasts. Much of their protein comes from fish. What happens when ocean acidification turns all of that to slime?

So what should we tell kids about climate?

It always helps to be open to advice from different settings. For instance, I stumbled on this good advice on a blog aimed at military spouses, but it strikes me that it holds just as true for the climate-concerned:

It is okay to show sadness around your kids; in fact, it is probably healthy. However, it is not okay to dump your emotions on them. Save rants and deep conversations for trusted adults.

If you are feeling overwhelmed (and you will), don’t turn to your kids. Children are usually helpless to offer advice and it can cause them to experience anxiety. Seek help from an adult friend … extended family, a neighbor, your church, or a counselor.

Sophie Lewis sensibly hopes that the next generation(s) “can be more empathetic, more creative and more responsive than we have been”. It’s a noble hope, but it will only happen if we behave differently.

So as previously in this column, it’s over to you, the readers. I have a couple of questions for you:

First, how do those of you who are parents (and grandparents, aunts and uncles) talk to your children about the climate change impacts that will happen in their lifetimes? Avoidance? Sugar-coating? The “straight dope”? Do you slip books from the burgeoning fields of dystopian fiction and “cli-fi” into their Christmas stockings? Besides The Hunger Games, there is Tomorrow, When the War Began, the excellent Carbon Diaries and, more recently, James Bradley’s The Silent Invasion. Do you worry about scaring the kids? What do the youngsters themselves say?

Second, what steps are you taking to help young people develop the (practical and interpersonal) skills required to survive as times get tougher? What are those skills? How do we make sure that it isn’t just the few (children of the rich and/or the “switched on”) who gain these skills?

'Tropics' may conjure images of sun-kissed islands, but the expanding tropical zone could bring drought and cyclones further south. Pedro Fernandes/Flickr, CC BY-SA

The Tropics are defined as the area of Earth where the Sun is directly overhead at least once a year — the zone between the Tropics of Cancer and Capricorn.

However, tropical climates occur within a larger area about 30 degrees either side of the Equator. Earth’s dry subtropical zones lie adjacent to this broad region. It is here that we find the great warm deserts of the world.

Earth’s bulging waistline

Earth’s tropical atmosphere is growing in all directions, leading one commentator to cleverly call this Earth’s “bulging waistline”.

Since 1979, the planet’s waistline been expanding poleward by 56km to 111km per decade in both hemispheres. Future climate projections suggest this expansion is likely to continue, driven largely by human activities – most notably emissions of greenhouse gases and black carbon, as well as warming in the lower atmosphere and the oceans.

If the current rate continues, by 2100 the edge of the new dry subtropical zone would extend from roughly Sydney to Perth.

As these dry subtropical zones shift, droughts will worsen and overall less rain will fall in most warm temperate regions.

Poleward shifts in the average tracks of tropical and extratropical cyclones are already happening. This is likely to continue as the tropics expand further. As extratropical cyclones move, they shift rain away from temperate regions that historically rely upon winter rainfalls for their agriculture and water security.

Researchers have observed that, as climate zones change, animals and plants migrate to keep up. But as biodiversity and ecosystem services are threatened, species that can’t adjust to rapidly changing conditions face extinction.

In some biodiversity hotspots – such as the far southwest of Australia – there are no suitable land areas (only oceans) for ecosystems and species to move into to keep pace with warming and drying trends.

We are already witnessing an expansion of pests and diseases into regions that were previously climatically unsuitable. This suggests that they will attempt to follow any future poleward shifts in climate zones.

I recently drew attention to the anticipated impacts of an expanding tropics for Africa. So what might this might mean for Australia?

IPCC Australia is vulnerable

Australia’s geographical location makes it highly vulnerable to an expanding tropics. About 60% of the continent lies north of 30°S.

As the edge of the dry subtropical zone continues to creep south, more of southern Australia will be subject to its drying effects.

Meanwhile, the fringes of the north of the continent may experience rainfall and temperature conditions that are more typical of our northern neighbours.

The effects of the expanding tropics are already being felt in southern Australia in the form of declining winter rainfall. This is especially the case in the southwest and — to a lesser extent — the continental southeast.

Future climate change projections for Australia include increasing air and ocean temperatures, rising sea levels, more hot days (over 35℃), declining rainfall in the southern continental areas, and more extreme fire weather events.

For northern Australia, changes in annual rainfall remain uncertain. However, there is a high expectation of more extreme rainfall events, many more hot days and more severe (but less frequent) tropical cyclones and associated storm surges in coastal areas.

Dealing with climate change

Adaptation to climate change will be required across all of Australia. In the south the focus will have to be on adapting to projected drying trends. Other challenges include more frequent droughts, more warm spells and hot days, higher fire weather risk and rising sea levels in coastal areas.

The future growth of the north remains debatable. I have already pointed out the lack of consideration of climate change in the White Paper for the Development of Northern Australia.

The white paper neglects to explain how planned agricultural, mining, tourism and community development will adapt to projected changes in climate over coming decades — particularly, the anticipated very high number of hot days.

For example, Darwin currently averages 47 hot days a year, but under a high carbon emission scenario, the number of hot days could approach 320 per year by 2090. If the north is to survive and thrive as a significant economic region of Australia, it will need effective climate adaptation strategies. This must happen now — not at some distant time in the future.

This requires bipartisan support from all levels of government, and a pan-northern approach to climate adaptation. It will be important to work closely with industry and affected local and Indigenous communities across the north.

These sectors must have access to information and solutions drawn from interdisciplinary, “public good” research. In the face of this urgent need, CSIRO cuts to such research and the defunding of the National Climate Change Adaptation Research Facility should be ringing alarm bells.

As we enter uncharted climate territory, never before has public-good research been more important and relevant.

Steve Turton has previously received funding from the Australian Government.

Mud oysters played a largely unappreciated part in Australia's history. Cayne Layton, Author provided

The largest oyster reef restoration project outside the United States is underway in the coastal waters of Gulf St Vincent, near Ardrossan in South Australia. Construction began earlier this month. Some 18,000 tonnes of limestone and 7 million baby oysters are set to provide the initial foundations for a 20-hectare reef.

The A$4.2-million project will be built in two phases and should be complete by December 2018. The first phase is the 4-hectare trial currently being built by Primary Industries and Regions South Australia; the second phase will see the reef expand to 20 hectares, led by The Nature Conservancy.

Some of the 18,000 tonnes of limestone destined for the seafloor. D. McAfee

Just 200 years ago the native mud oyster, Ostrea angasi, formed extensive reefs in the Gulf, along more than 1,500km of South Australia’s coastline. Today there are no substantial accumulations of mud oysters anywhere around mainland Australia, with just one healthy reef remaining in Tasmania.

This restoration project aims to pull our native mud oyster back from the brink of extinction in the wild, and restore a forgotten ecosystem that once teemed with marine life.

More than just seafood

Oysters played a large role in Australia’s colonial history. When European settlers first arrived they had to navigate a patchwork of oyster reefs (also called shellfish reefs) that filled the shallow waters of our temperate bays. These enormous structures could cover 10 hectares in a single patch, providing an easily exploited food resource for the struggling early settlers. Oyster shell was burned to produce lime, and the colony’s first buildings were built with the help of oyster cement.

Collectively, these pre-colonial oyster reefs would have rivalled the geographic extent of the Great Barrier Reef, covering thousands of kilometres of Australia’s eastern and southern coastlines.

The history goes back much further too. For thousands of years oyster reefs fed and fuelled trade among Aboriginal communities. Shell middens dating back 2,000 years attest to the cultural importance of oysters for coastal communities, who ate them in abundance and used their shells to fashion fishhooks and cutting tools.

Health oyster reef in Tasmania. C. Gillies

The insatiable appetite of the newly settled Europeans for this bountiful resource was devastating. Not only were live oysters harvested for food, but the dead shell foundations that are critical for the settlement of new oysters were scraped from the seabed for lime burning. Armed with bottom-dredges a wave of exploitation spread across the coast, first overexploiting oyster reefs close to major urban centres and then further afield. The combination of the lost hard shell bed and increased sediment runoff from the rapidly altered coastal landscape saw oyster populations crash within a century of colonisation.

Today oyster populations are at less than 1% of their pre-colonial extent in Australia. This is not a unique story – globally it is estimated that 85% of oyster habitat has been lost in the past few centuries, making it one of the most exploited marine habitats in the world.

Today, across much of Australia’s east coast you will see Sydney rock oysters encrusting rocky shores, creating a thin veneer around the edge of our bays and estuaries. On the south coast you occasionally see a solitary mud oyster clinging to a jetty pylon. Many Australians don’t realise that this familiar sight represents a mere shadow of the incredible and largely forgotten ecosystems that oysters once supported.

Oysters are an unsung ecological superhero, with the capacity to increase marine biodiversity, clean coastal waters, enhance neighbouring seagrass, reduce coastal erosion, and even slow the rate of climate change. When oysters cement together, their aggregations form habitat for a great diversity of other invertebrates. A 25cm-square patch of oysters can host more than 1,000 individual invertebrates from a range of different biological groups, in turn providing a smorgasbord for fish.

Restoration site, formerly covered with dense oyster habitat. D. McAfee

A solitary oyster can filter about 100 litres of water a day, which means that en masse they can function as the “kidneys” of our bays, filtering excess nutrients from the water and depositing them on the seafloor. In doing so, they encourage seagrass growth, while their physical structures help to dissipate wave energy and thus reduce the impact of storm surges.

As if all that weren’t enough, oysters are also a carbon sink, building calcium carbonate shells that are buried in the seafloor after death and eventually compacted to rock, thus helping to prevent carbon dioxide from cycling back into the atmosphere.

Building it back

Restoring oyster reefs has the potential to return these ecosystem services and increase the productivity of our coastal ecosystems. The Gulf of St Vincent project came about through an election promise by the South Australian Government to boost recreational fishing. A collaboration between The Nature Conservancy, Yorke Penninsula Council and the South Australian Government will deliver the reef’s foundations, while my colleagues and I at the University of Adelaide are working to ensure that the restored oysters survive and thrive, and that the reef continues to grow.

Hopefully this is just the beginning for large-scale oyster restoration in Australia, and the lessons learned from this project will guide more restoration projects to improve the health of our oceans. With other restoration projects also underway in Victoria and Western Australia, the tide is hopefully turning for our once numerous oysters.

Sean Connell receives funding from The Ian Potter Foundation and Department of Environment Water and Natural Resources and The Environment Institute of The University of Adelaide for this research.

Dominic McAfee 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 mass enters the ocean from glaciers such as this along the Greenland coast. NASA/JPL-Caltech

Contributions to the rate of global sea-level rise increased by about half between 1993 and 2014, with much of the increase due to an increased contribution from Greenland’s ice, according to our new research.

Our study, published in Nature Climate Change, shows that the sum of contributions increased from 2.2mm per year to 3.3mm per year. This is consistent with, although a little larger than, the observed increase in the rate of rise estimated from satellite observations.

Globally, the rate of sea-level rise has been increasing since the 19th century. As a result, the rate during the 20th century was significantly greater than during previous millennia. The rate of rise over the past two decades has been larger still.

The rate is projected to increase still further during the 21st century unless human greenhouse emissions can be significantly curbed.

However, since 1993, when high-quality satellite data collection started, most previous studies have not reported an increase in the rate of rise, despite many results pointing towards growing contributions to sea level from the ice sheets of Greenland and Antarctica. Our research was partly aimed at explaining how these apparently contradictory results fit together.

Changes in the rate of rise

In 2015, we completed a careful comparison of satellite and coastal measurements of sea level. This revealed a small but significant bias in the first decade of the satellite record which, after its removal, resulted in a slightly lower estimate of sea-level rise at the start of the satellite record. Correcting for this bias partially resolved the apparent contradiction.

In our new research, we compared the satellite data from 1993 to 2014 with what we know has been contributing to sea level over the same period. These contributions come from ocean expansion due to ocean warming, the net loss of land-based ice from glaciers and ice sheets, and changes in the amount of water stored on land.

Previously, after around 2003, the agreement between the sum of the observed contributions and measured sea level was very good. Before that, however, the budget didn’t quite balance.

Using the satellite data corrected for the small biases identified in our earlier study, we found agreement with the sum of contributions over the entire time from 1993 to 2014. Both show an increase in the rate of sea-level rise over this period.

The total observed sea-level rise is the sum of contributions from thermal expansion of the oceans, fresh water input from glaciers and ice sheets, and changes in water storage on land. IPCC

After accounting for year-to-year fluctuations caused by phenomena such as El Niño, our corrected satellite record indicates an increase in the rate of rise, from 2.4mm per year in 1993 to 2.9mm per year in 2014. If we used different estimates for vertical land motion to estimate the biases in the satellite record, the rates were about 0.4mm per year larger, changing from 2.8mm per year to 3.2mm per year over the same period.

Is the whole the same as the sum of the parts?

Our results show that the largest contribution to sea-level rise – about 1mm per year – comes from the ocean expanding as it warms. This rate of increase stayed fairly constant over the time period.

The second-largest contribution was from mountain glaciers, and increased slightly from 0.6mm per year to 0.9mm per year from 1993 to 2014. Similarly, the contribution from the Antarctic ice sheet increased slightly, from 0.2mm per year to 0.3mm per year.

Strikingly, the largest increase came from the Greenland ice sheet, as a result of both increased surface melting and increased flow of ice into the ocean. Greenland’s contribution increased from about 0.1mm per year (about 5% of the total rise in 1993) to 0.85mm per year (about 25% in 2014).

Greenland’s contribution to sea-level rise is increasing due to both increased surface melting and flow of ice into the ocean. NASA/John Sonntag, CC BY

The contribution from land water also increased, from 0.1mm per year to 0.25mm per year. The amount of water stored on land varies a lot from year to year, because of changes in rainfall and drought patterns, for instance. Despite this, rates of groundwater depletion grew whereas storage of water in reservoirs was relatively steady, with the net effect being an increase between 1993 and 2014.

So in terms of the overall picture, while the rate of ocean thermal expansion has remained steady since 1993, the contributions from glaciers and ice sheets have increased markedly, from about half of the total rise in 1993 to about 70% of the rise in 2014. This is primarily due to Greenland’s increasing contribution.

What is the future of sea level?

The satellite record of sea level still spans only a few decades, and ongoing observations will be needed to understand the longer-term significance of our results. Our results also highlight the importance of the continued international effort to better understand and correct for the small biases we identified in the satellite data in our earlier study.

Nevertheless, the satellite data are now consistent with the historical observations and also with projected increases in the rate of sea-level rise.

Ocean heat content fell following the 1991 volcanic eruption of Mount Pinatubo. The subsequent recovery (over about two decades) probably resulted in a rate of ocean thermal expansion larger than from greenhouse gases alone. Thus the underlying acceleration of thermal expansion from human-induced warming may emerge over the next decade or so. And there are potentially even larger future contributions from the ice sheets of Greenland and Antarctica.

The acceleration of sea level, now measured with greater accuracy, highlights the importance and urgency of cutting greenhouse gas emissions and formulating coastal adaptation plans. Given the increased contributions from ice sheets, and the implications for future sea-level rise, our coastal cities need to prepare for rising sea levels.

Sea-level rise will have significant impacts on coastal communities and environments. Bruce Miller/CSIRO, CC BY

John Church previously received funding from Australian Climate Change Research Program.

Christopher Watson receives funding from the Australian Research Council and the NCRIS Integrated Marine Observing System.

Matt King receives funding from Australian Research Council and Department of Environment.

Xianyao Chen received funding from the National Key Basic Research Program of China and the Natural Science Foundation of China.

Xuebin Zhang received funding from Pacific Climate Change Science Program (PCCSP) and follow-up Pacific-Australia Climate Change Science and Adaptation Planning program (PACCSAP) both of which were funded by the Australian Government’s International Climate Change Adaptation Initiative, and also from Australian Climate Change Science Programme (ACCSP), National Environmental Science Programme (NESP), and Centre for Southern Hemisphere Ocean Research (CSHOR).