The Conversation

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).

According to the WWF, we're living off 1.6 Earths' worth of resources. Kevin Gill/Flickr, CC BY-SA

Since the 1970s, humans have used more resources than the planet can regenerate. This is known as overshoot. The WWF Living Planet Report has reported overshoot every two years since 2000.

However, this fact can inspire some confusion. How can it logically be possible for us to use more resources than Earth can produce, for decades on end?

There are two basic concepts at work here. One is our ecological footprint, which can be very loosely understood as a way of tallying up the resources we use from nature. The other is the planet’s ability to provide or renew those resources every year: its “biocapacity”.

When our ecological footprint exceeds Earth’s biocapacity, that’s unsustainable resource use. Unsustainable resource use can occur for some time. The environmental thinker Donella Meadows used a bathtub analogy to explain how.

Imagine a bathtub full of water, with the tap running and the plug out at the same time. It is possible for more water to flow out of the bath than into it for some time without the water in the tub running out. This is because the significant store of water in the bath acts like a buffer. The same goes for nature.

Because nature has accumulated resources – for example, in a forest – it’s possible for us to harvest nature at a greater rate than it can replenish itself for a certain amount of time.

But this leads to the question: if humanity’s ecological footprint exceeds Earth’s biocapacity, how long can we keep going without crossing a tipping point? Our recent research investigates this question.

Explaining the feedback system

It’s important to make the point that nature provides us with literally everything we need, through processes known as ecosystem services. Much of this is obvious because we buy and sell it, as food, shelter and clothing.

Other services go largely unnoticed. Forests provide protection from flooding by slowing down surface water runoff, for example, while mangroves absorb carbon dioxide from the air and store it. Until relatively recently, nature has continued to provide, despite our rapidly increasing ecological footprint.

In part this resilience comes from being able to buffer disturbance with the existing store of resources. But there’s an important mechanism that helps natural systems adjust – to a certain extent – to disruption. This is called a feedback mechanism, and if we take the bathtub analogy one step further we can see how it works.

Say we set up our bathtub so that the tap and the plughole communicate with one another. If more water suddenly starts flowing down the plug, then the tap increases the flow of water into the bath to compensate, thus maintaining the water level. This is an example of a “positive” feedback (more water exiting the bath) being moderated by a “negative” feedback (more water entering from the tap), thus maintaining the state of the system (water in the bath).

Let’s pick a real-world example. Clearing trees from a forest might mean that seeds from the soil have the chance to germinate. If they germinate before the landscape gets too degraded, they can potentially balance out the disturbance.

But harvesting forest also exposes the ground, causing soil loss. In turn, vegetation might find it more difficult to regrow – resulting in yet more soil loss, and so on. This is a “positive” feedback – one that reinforces and exacerbates the original problem.

Negative feedbacks can only adapt to a certain level of disruption. Once the disturbance is too large, they break down. Positive feedback loops can then prevail and the ecosystem is likely to cross a tipping point, resulting in permanent, dramatic and sudden transformation.

Crossing planetary boundaries

In our research, my colleagues and I compared future ecological footprints with research about planetary boundaries (points at which the risks to humanity of crossing a tipping point become unacceptably high). We found the discrepancy between the ecological footprint and biocapacity is likely to continue until at least 2050. We also found that our global cropping footprint is likely to exceed the planetary boundary for land clearing between 2025 and 2035.

This occurs in the context of atmospheric carbon dioxide concentrations that have already crossed the planetary boundary of 350 ppm. (As I write, the carbon dioxide concentration is over 400 ppm.)

By itself, both these points are serious enough. More seriously, we have no idea what happens when two planetary boundaries are approached simultaneously, or two tipping points interact.

We face the permanent loss of essential natural processes, putting, for example, our global food security at risk. Our research shows we need to address gradual, cumulative change, as the global resource buffer shrinks and stabilising feedback mechanisms are overwhelmed.

But there’s good news too. Ecological footprints decrease in response to human decisions. Our current trajectory towards tipping points is not fait accompli at all, but can be influenced by the choices we make now.

Bonnie McBain received ARC funding for this research.

The famous "faceless fish", which garnered worldwide headlines when it was collected by the expedition. Rob Zugaro, Author provided

Over the past five weeks I led a “voyage of discovery”. That sounds rather pretentious in the 21st century, but it’s still true. My team, aboard the CSIRO managed research vessel, the Investigator, has mapped and sampled an area of the planet that has never been surveyed before.

The RV Investigator in port. Jerome Mallefet/FNRS

Bizarrely, our ship was only 100km off Australia’s east coast, in the middle of a busy shipping lane. But our focus was not on the sea surface, or on the migrating whales or skimming albatross. We were surveying The Abyss – the very bottom of the ocean some 4,000m below the waves.

To put that into perspective, the tallest mountain on the Australian mainland is only 2,228m. Scuba divers are lucky to reach depths of 40m, while nuclear submarines dive to about 500m. We were aiming to put our cameras and sleds much, much deeper. Only since 2014, when the RV Investigator was commissioned, has Australia had the capacity to survey the deepest depths.

The months before the trip were frantic, with so much to organise: permits, freight, equipment, flights, medicals, legal agreements, safety procedures, visas, finance approvals, communication ideas, sampling strategies – all the tendrils of modern life (the thought “why am I doing this?” surfaced more than once). But remarkably, on May 15, we had 27 scientists from 14 institutions and seven countries, 11 technical specialists, and 22 crew converging on Launceston, and we were off.

Rough seas

Life at sea takes some adjustment. You work 12-hour shifts every day, from 2 o’clock to 2 o’clock, so it’s like suffering from jetlag. The ship was very stable, but even so the motion causes seasickness for the first few days. You sway down corridors, you have one-handed showers, and you feel as though you will be tipped out of bed. Many people go off coffee. The ship is “dry”, so there’s no well-earned beer at the end of a hard day. You wait days for bad weather to clear and then suddenly you are shovelling tonnes of mud through sieves in the middle of the night as you process samples dredged from the deep.

Shifting through the mud of the abyss on the back deck. Jerome Mallefet/FNRS

Surveying the abyss turns out to be far from easy. On our very first deployment off the eastern Tasmanian coast, our net was shredded on a rock at 2,500m, the positional beacon was lost, tens of thousands of dollars’ worth of gear gone. It was no one’s fault; the offending rock was too small to pick up on our multibeam sonar. Only day 1 and a new plan was required. Talented people fixed what they could, and we moved on.

I was truly surprised by the ruggedness of the seafloor. From the existing maps, I was expecting a gentle slope and muddy abyssal plain. Instead, our sonar revealed canyons, ridges, cliffs and massive rock slides – amazing, but a bit of a hindrance to my naive sampling plan.

But soon the marine animals began to emerge from our videos and samples, which made it all worthwhile. Life started to buzz on the ship.

Secrets of the deep

Like many people, scientists spend most of their working lives in front of a computer screen. It is really great to get out and actually experience the real thing, to see animals we have only read about in old books. The tripod fish, the faceless fish, the shortarse feeler fish (yes, really), red spiny crabs, worms and sea stars of all shapes and sizes, as well as animals that emit light to ward off predators.

A spiny red lithodid crab. Rob Zugaro/Museums Victoria The tripod fish uses its long spines to sit on the seafloor waiting for the next meal. Rob Zugaro/Museums Victoria

The level of public interest has been phenomenal. You may already have seen some of the coverage, which ranged from the fascinated to the amused – for some reason our discovery of priapulid worms was a big hit on US late-night television. In many ways all the publicity mirrored our first reactions to animals on the ship. “What is this thing?” “How amazing!”

The important scientific insights will come later. It will take a year or so to process all the data and accurately identify the samples. Describing all the new species will take even longer. All of the material has been carefully preserved and will be stored in museums and CSIRO collections around Australia for centuries.

Scientists identifying microscopic animals onboard. Asher Flatt

On a voyage of discovery, video footage is not sufficient, because we don’t know the animals. The modern biologist uses high-resolution microscopes and DNA evidence to describe the new species and understand their place in the ecosystem, and that requires actual samples.

So why bother studying the deep sea? First, it is important to understand that humanity is already having an impact down there. The oceans are changing. There wasn’t a day at sea when we didn’t bring up some rubbish from the seafloor – cans, bottles, plastic, rope, fishing line. There is also old debris from steamships, such as unburned coal and bits of clinker, which looks like melted rock, formed in the boilers. Elsewhere in the oceans there are plans to mine precious metals from the deep sea.

Rubbish found on the seafloor. Rob Zugaro/Museums Victoria

Second, Australia is the custodian of a vast amount of abyss. Our marine exclusive economic zone (EEZ) is larger than the Australian landmass. The Commonwealth recently established a network of marine reserves around Australia. Just like National Parks on land, these have been established to protect biodiversity in the long term. Australia’s Marine Biodiversity Hub, which provided funds for this voyage, as been established by the Commonwealth Government to conduct research in the EEZ.

The newly mapped East Gippsland Commonwealth Marine Reserve, showing the rugged end of the Australian continental margin as it dips to the abyssal plain. The scale shows the depth in metres. Amy Lau/CSIRO

Our voyage mapped some of the marine reserves for the first time. Unlike parks on land, the reserves are not easy to visit. It was our aim to bring the animals of the Australian Abyss into public view.

We discovered that life in the deep sea is diverse and fascinating. Would I do it again? Sure I would. After a beer.

Tim O'Hara receives research funding from the National Environmental Science Programme's Marine Biodiversity Hub.

Mick Tsikas/AAP

Despite the government still considering his proposal for a Clean Energy Target (CET) - after endorsing his other 49 recommendations - Chief Scientist Alan Finkel is optimistic that the CET remains firmly on the agenda.

Finkel’s challenging task has been to put forward a scheme to bring Australia’s energy market into the future, providing certainty for investment and supply. His plan has required a balance between appeasing consumers on prices, and meeting Australia’s commitments on climate change.

This is made harder by the desire of many in the government to push on with developing new ‘clean coal’ fired power stations, a term Finkel describes as “a murky concept”. “There is no prohibitions in any of our recommendations. The government has to decide whether to licence new technologies.” he says.

Asked about the concept of ‘reverse auctions’ - better called competitive tenders - he says this is “widely recognised to be the most cost-effective means of bringing the lowest cost solution into the market.” But that’s dependent on the wisdom of the entity running the auction rather than the wisdom of investors.

Overall, Finkel acknowledges there’s a hard road ahead for policy-making on energy: “transitions are always painful”.

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.

The birds commonly seen in urban backyards of Australia are increasingly introduced species like this house sparrow, sharing a birdbath with a native red-browed finch. Wanda Optland

While running the Australian Bird Feeding and Watering Study, I have been surveying people on whether they try to discourage undesirable birds from entering their gardens.

For the survey, I used the term “undesirable birds” for introduced species such as spotted doves or house sparrows. Judging by the volume of complaints I received, I may have misjudged this definition – introduced does not necessarily mean “undesirable”!

I was surprised to discover how much people appreciate the spotted doves, house sparrows, blackbirds and other “undesirables” that hang around their gardens. People care about these birds, even though ecologists officially consider them pests.

Two house sparrows can be seen here enjoying a bath among native New Holland honeyeaters. Wanda Optland

This raises an interesting question. Introduced birds are often considered to be pests, but does that necessarily mean we shouldn’t interact with or enjoy them at all?

House sparrows, spotted doves and Indian mynas dominate many urban areas, are dependent on us to survive, and appear to cause little damage to native species. There is very little peer-reviewed evidence of environmental impact of introduced birds on other species. Without us and our urban development, one wonders how common they would be.

In an increasingly urbanised world, many birds are having to adapt to a new habitat: the urban jungle. I live in a rented house in inner Melbourne, and in my very small garden I have two spotted doves and a family of house sparrows. I would love to have some small native birds visit me, but it’s almost certainly not going to happen because of where I live.

Many bird lovers are so concerned with encouraging native species that they feel guilty about enjoying the only birds that do visit. But should we care any less about them because they are introduced species? After all, it’s not as if my garden is getting much love from the natives – the local magpie ignores my entreaties, and the wattlebirds are too busy arguing over the bottlebrush trees that line our street. In their absence, why shouldn’t I form a bond with Mr and Mrs Spotted Dove who have been with me for three years? A spotted dove. Wanda Optland

Friendly feeders

It seems I am not the only one who feels this way. My preliminary survey results suggest that many people get pleasure from helping wild birds, whether by providing food, water or somewhere for them to live. As many species are relatively long-lived, the same birds visit time and again, and some people even consider them part of their household.

Some respondents said they find that birds alleviate anxiety and depression, or as one of my citizen scientists put it:

I try to feed birds responsibly because it lifts my depression. Connects me to nature. Makes me happy.

Another told me:

The emotional feeling watching the birds is better than any pill.

For many respondents, the relationship with individual birds seems to matter more than whether or not they are a native species. As another respondent told me:

I feel that I have a relationship with the birds that come to my garden. Some of them sit on the patio and wait for me.

A spotted dove seen on the left shares a cool spot in the backyard with a native double-barred finch. Wanda Optland

I can relate. My two spotted doves are always in my garden, and will follow me around until I give them some seeds. They provide great entertainment for my two indoor cats who watch through the flyscreen. I feel connected to them, despite any lingering guilt about encouraging non-native species.

Native to where?

As with most things in life, this issue is far from black and white anyway. With the possible exception of a magpie’s familiar warbling song, what could be more Aussie than the sound of laughing kookaburras? But did you know that they are non-native to Western Australia and Tasmania? It’s a similar story for rainbow lorikeets, whose colourful plumage is a common sight in and around Perth despite them being non-native there.

What about less lovable species, such as the Indian mynas, also called common mynas, and rock doves, also known as feral pigeons or (rather less kindly) “flying rats”?

An introduced bird species, Indian mynas are commonly seen in urban gardens of eastern Australia. Wanda Optland

Indian mynas do particularly well in many urban areas such as Brisbane, Melbourne and Sydney. This is partly because of the prevalence of large gumtrees with little or no understorey, which reflect very closely their natural habitat. Could it be that their success is largely down to us?

Rock doves also get a very bad rap, despite being descended from war pigeons that were credited with saving hundreds of human lives. Think about that the next time one gives you the eye while you eat your lunch in the city!

So should we feel guilty for loving introduced birds? If caring for birds is good for our mental health, then perhaps the answer is no, even though we want to see native species thrive wherever possible. Do you provide food or water for introduced birds? I would love to see your comments.

Often we have little choice anyway. Sometimes, because of where we live, introduced birds are the only ones who care to interact with us. As much as I would love to see an Australian king parrot visit my little Melbourne backyard, I will probably have to be content with just my spotted doves and house sparrows for company.

Grainne Cleary received a small grant from Mars BirdCare to help support her research

Numbers of skylarks have declined dramatically in western Europe. from www.shutterstock.com, CC BY-ND

New Zealand has an audacious plan to protect its native birds. The country has pledged to rid itself of introduced mammalian predators by 2050 and, this year, will spend $20 million on the Battle for the Birds, one of the largest predator control programmes in the country’s history, across more than 800,000 hectares of land.

Of the 168 bird species that are native to New Zealand, four in five are in trouble, according to a report published last month by the Parliamentary Commissioner for the Environment. New Zealand’s native birds deserve all the help they can get, but this should not detract from the fact that new data show that several introduced bird species are also disappearing.

European settlers arrive with avian cargo

The early settlers brought 130 bird species to New Zealand, and 41 of them established. Given that in lowland areas in the Canterbury province, for example, less than 1% of the original biodiversity remains, perhaps we should place greater value on non-native biodiversity, faute de mieux.

Not everybody agrees with the value of non-native birds. In 1883, Te Whiti was the leader of a peaceful resistance movement at Parihaka, protesting about the sometimes violent confiscation of land by European settlers. He cared about endemic fauna and wrote: “it was not good work bringing those birds out here; they eat all the potatoes and the oats; they are not good birds to bring out … were there not plenty of good birds in New Zealand that eat no man’s food?”

A key recent development, however, which appears to be raising New Zealanders’ awareness of the value of introduced birds is the New Zealand Garden Bird Survey, organised by Eric Spurr of Landcare Research. This is an example of well-managed citizen science, garnering the help of New Zealanders to make systematic observations. After a decade of data gathering, the results show that at least six non-native species - starling, song thrush, blackbird, goldfinch, chaffinch, and dunnock - have declined since the survey started.

Silent gardens

The counts are only of birds in gardens, and the reasons for the declines have not been determined, but the picture is beginning to mirror the dramatic declines in bird populations in Europe over the last 40 years. Even the common starling is declining in Britain, at the rate of 150 birds for every hour since the 1980s. The skylark too has suffered dramatic changes in its numbers in western Europe. A major decline of 75% between 1972 and 1996 put in the Red List.

In Europe, these birds have played an enormous part in art, poetry and literature for hundreds of years. One is reminded of the poem The Lark Ascending by Meredith, and Vaughan Williams’ music on the same theme. In art, birds such as the goldfinch have featured in work by Fabritius and Tiepolo, and throughout the Renaissance period this bird’s blood-red face and its habit of feeding on thorny thistles led to its association with Christ on the cross. Even the Beatles sang a song called Blackbird, in 1968.

In New Zealand, introduced bird species do not seem to generate the same level of affection as endemic ones, such as the tui. In Canterbury, flocks of rooks, which are a key part of the English countryside, were common, but they have been poisoned and shot almost to extinction.

Nature’s health benefits

International research is clearly showing the restorative benefits of “a dose of nature”, such as a walk in the countryside. Recently, Lin Roberts and colleagues at Lincoln University wrote a major report for the New Zealand Department of Conservation which analysed and quantified the contribution of native ecosystems to New Zealanders’ mental health. However, we can’t afford to ignore the contribution that our non-native flora and fauna make to our sense of place and well-being.

It is quite possible that the contribution which introduced bird species make to New Zealand is also delivering other ecosystem functions and services. They eat weed seeds and pest insects, pollinate native shrubs and trees and distribute the seeds of native and endemic plants, just as our endemic birds used to do before their numbers were drastically reduced by New Zealand’s introduced predator fauna.

In Britain, urbanisation, fragmentation of the countryside and intensification of agriculture are being associated with these huge losses. In New Zealand, there have been dramatic changes in the farming landscape over the last decade or so. Are these changes likely to impact on the surveys of garden birds? It would be foolish to speculate too boldly on whether farming intensification has impacts on garden bird numbers as there is no serious monitoring of farmland birds.

However, any declines there could be yet another warning of this country’s biodiversity loss. Male skylarks used to sing in the sky above my house when we were surrounded by low-intensity farming, but now I see and hear virtually none. We are beginning to lose our under-valued introduced bird species and this should be a cause for concern.

Stephen D Wratten 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.

Australians should be deeply concerned about the signals coming from the Turnbull government since this month’s release of Chief Scientist Alan Finkel’s landmark report on the future of Australia’s electricity system.

On Tuesday the government announced a new package of policies for the electricity sector. This includes asking the Australian Energy Market Operator (AEMO) to look at “how to ensure that new continuous dispatchable power is provided, including what support is needed to promote new investment”.

Effectively, the government is asking AEMO to identify whether Australia has enough “baseload” generation and, if not, how the government should go about getting more.

In simple terms this marks a further reversion to central planning, either purposely by stealth, or accidentally through ignorance. The rushed nature of the announcement, without any forewarning, suggests the latter.

Going to plan?

Central planning can provide politicians with the illusion of certainty and control. When governments don’t see the outcomes they want in the market – in this case reliable and affordable energy (and, for some politicians, new coal-fired power stations) – taking command offers them the opportunity to deliver those outcomes.

But this presumes that governments know better than the market. History tells us they don’t. The result is often expensive and excessive building of new generation that does not guarantee reliable supply.

Some see this policy as the government walking away from its obligation to reduce emissions in the electricity sector. Others believe it signals success for the Minerals Council Australia (MCA) in its push to have the government build new coal-fired power stations.

The MCA has reportedly urged the cabinet to embrace a “reverse auction” scheme instead of the Clean Energy Target (CET) recommended by Finkel. Under a reverse auction scheme, the government would tender for new electricity generation. The lowest bid wins, and the winning bidder would receive a contract guaranteeing revenue for the electricity it generates.

Certainly, if the government were to choose a mechanism to procure new electricity generation, reverse auctions look like the obvious policy. Such auctions are common; indeed, the federal government already uses them to buy emissions reductions from a range of economic sectors under the Emissions Reduction Fund. The ACT government also uses them to procure large-scale renewable energy.

But reverse auctions are generally not used as a central climate change policy. Instead, they operate alongside emissions-reduction polices to encourage the development of specific types of generation technologies. In Germany, for example, reverse auctions are being used to incentivise new wind generation. The MCA will doubtless be hoping that the auctions specifically call for new, cleaner coal technologies.

Let’s be clear. The government’s announcement does not go as far as the MCA’s proposal. AEMO appears to have the responsibility for determining whether and how new electricity generation will be bought to market, and the government has not rejected Finkel’s CET proposal.

But nor is the announcement simply the government pressing forward with the “strategic reserve” suggested by Finkel. A strategic reserve is an insurance policy, ensuring enough backup generation is available in case something goes wrong in the market. Prime Minister Malcolm Turnbull’s announcement on Tuesday indicates that new generation will not simply be built as backup, but will play an active role in the market. After all, baseload generation is useless if it sits there and does nothing.

Proceed with caution

There are numerous reasons to be concerned about this announcement. It is not clear how such a proposal would work with any emissions-reduction scheme such as a CET. Providing simultaneous incentives for low-emissions generation through a CET and for “baseload” generation through a separate scheme sounds like a recipe for an expensive, unreliable system. And it would make meeting Australia’s emissions targets more complex.

Nor is it clear that Australia even needs more “baseload” generation at the moment. Signals in the electricity market suggest that if Australia needs anything it is flexible generation that can respond to sudden changes in demand and supply. This is not coal; it is gas, or perhaps battery storage.

Most of all, the announcement follows a broader trend of increasing government involvement in the electricity market. Whether it is the Commonwealth with its proposed Snowy 2.0 scheme, South Australia’s plan to build a state-owned gas power station, or Queensland’s manipulation of wholesale prices, electricity is now government business.

Anyone who thought the Finkel Review might bring some much-needed policy certainty to the electricity market is being rapidly disabused of that idea. Instead of fostering investor confidence, the government has just telegraphed the fact that it is prepared to intervene directly in the market. Any risk-averse investor will run away as fast as they can.

Once government starts intervening in the market, it will have to keep doing so. If you listen closely, you can hear the sound of two decades of market primacy in the electricity sector being flushed down the toilet.

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

Australia is renowned worldwide for our venomous and poisonous creatures, from snakes, spiders and ticks on land, to lethal jellyfish, stingrays and stonefish in our waters. Even the shy platypus can inflict excruciating pain if handled without due care.

Yet while injuries and deaths caused by venomous snakes and jellyfish are often sensationalised in the media, and feared by international visitors, a recent review found that very few “deadly” Australian animals actually cause deaths. Between 2000 and 2013, there were two fatalities per year from snake bites across Australia, while the average for bee stings was 2.2 and for jellyfish 0.25, or one death every four years. For spiders – including our notorious redbacks and Sydney funnel-webs – the average was zero.

Snakes nevertheless strike fear into many people who live in or visit Australia. When we have a higher risk of injury or death from burns, horses, bee stings, drownings and car accidents, why don’t we fear these hazards as we do the sight of a snake?

Snakes and statistics through history James Bray, Venomous and Non-Venomous Reptiles (1897). State Library of NSW/Peter Hobbins

When settlers arrived in Australia in the late 18th century, they believed that Australian snakes were harmless. By 1805 it was accepted that local serpents might kill humans, but they were hardly feared in the same way as the American rattlesnake or Indian cobra.

Until the 1820s, less than one human death from snake bite was recorded each year; in 1827 visiting surgeon Peter Cunningham remarked that:

…comparatively few deaths [have] taken place from this cause since the foundation of the colony.

Similar observations were made into the 1840s. What the colonists did note, however, was the significant death toll among their “exotic” imported animals, from cats and sheep to highly valuable horses and oxen.

By the 1850s, living experiments in domestic creatures – especially chickens and dogs – were standard fare for travelling antidote sellers. Given the popularity of these public snake bite demonstrations, from the 1860s, doctors and naturalists also took to experimenting with captive animals. It was during this period that official statistics on deaths began to be collated across the Australian colonies.

One sample from 1864–74, for instance, reported an average of four snake bite deaths per year across Victoria, or one death per 175,000 colonists. In contrast, during the same period one in 6,000 Indians died from snake bites each year; little wonder that around the world, Australian snakes were considered trifling.

The 1890s represented a dramatic period of divergence, though. On one hand, statistical studies in 1882–92 suggested that on average, 11 people died annually from snake bite across Australia. Similar data compiled in Victoria led physician James Barrett to declare in 1892 that snakes posed “one of the most insignificant causes of death in our midst”. On the other hand, by 1895 standardised laboratory studies, aimed especially at producing an effective antivenom, saw a global recognition that Australian snake venoms were among the most potent in the world.

In Sydney, physiologist Charles Martin claimed that Australian tiger snake venom was as powerful as that of the cobra. In 1902, his collaborator Frank Tidswell ranked local tiger snake, brown snake and death adder venoms at the top of the global toxicity table.

Over the ensuing century, this paradox has remained: why do so few Australians die from snake bites when our serpents have the world’s most potent venoms? Why aren’t they more deadly?

Deadly fear

Scientific research has delivered ever-expanding knowledge about venoms, what they do, how they work, how they affect us clinically, and their comparative “potency” based on animal studies. In response we have introduced first aid measures, guidelines, effective clinical management and treatment, which in Australia forms one of the world’s best emergency health care systems.

In contrast, countries where snakebites cause far more deaths generally face challenges in accessing affordable essential medicines, prevention and education options.

Snakes form an essential part of their ecosystems. They do not “attack” humans, mostly being shy animals, but are defensive and prefer to escape.

It would seem that venom potency is not a good measure of deadliness, and it may be a combination of our history, behaviour and belief that creates a cultural fear.

Without understating the potential danger posed by venomous snakes, what we offer instead is reassurance. As nearly two centuries of statistics and clinical experience suggest, most snake bites in Australia are survivable, if managed quickly, calmly and effectively. In fact, encounters with humans all too often prove deadly to the snakes themselves – a paradox that is within our power to change.

The authors are presenting on this topic at the upcoming Emerging Issues in Science and Society event at Deakin University’s Downtown campus on 6 July 2017. Sponsored by the Australian Academy of Science and Deakin University’s Science and Society Network.

The event brings together scientists with humanities and social science scholars to discuss common questions from different angles. For more information on the event and to book tickets see the event’s website.

Ronelle Welton receives funding from the NHMRC.

Peter Hobbins received an Australian Postgraduate Award to undertake his PhD on the subject of snakebite in colonial Australia, and was the 2016 Merewether Fellow at the State Library of New South Wales, which entailed research on a similar topic.

Getting your strata committee to agree to solar panels is tricky, but it can be done. Stucco, Author provided

While there are now more solar panels in Australia than people, the many Australians who live in apartments have largely been locked out of this solar revolution by a minefield of red tape and potentially uninformed strata committees.

In the face of these challenges, Stucco, a small co-operative housing block in Sydney, embarked on a mission to take back the power. Hopefully their experiences can serve as a guide to how other apartment-dwellers can more readily go solar.

From an energy perspective, Stucco was a typical apartment block: each of its eight units had its own connection to the grid and was free to choose its own retailer, but was severely impeded from choosing to supply itself with on-site renewable energy.

Things changed in late 2015 when the co-op was awarded an Innovation Grant from the City of Sydney with a view to becoming the first apartment block in Australia to be equipped with solar and batteries.

A central part of Stucco’s plan was to share the locally produced renewable energy by converting the building into an “embedded network”, whereby the building has a single grid connection and manages the metering and billing of units internally.

Such a conversion seemed like an ideal solution for solar on apartments, but turned into an ideological battle with the electricity regulator that took months and hundreds of hours of pro bono legal support to resolve.

Layout of Stucco as solar powered embedded network. Sonia Millway

In this way the Stucco project grew to embody the struggle at the heart of the Australian electricity market: a battle between choice and control, between current regulations that mandate consumers to choose between incumbent retailers, and the public’s aspirations for green self-sufficiency.

A chicken and egg problem

Embedded networks have been around for decades. Yet if the Australian Energy Regulator had its way, they would be banned as soon as possible.

The reason for this is that they inhibit consumers’ choice of retailer: consumers are forced to buy their electricity from the building’s embedded network management company, which may exploit its monopoly power.

Yet it doesn’t have to be this way. At least one company in Germany allows apartment residents to buy power either from their preferred grid retailer or from the building’s solar-powered embedded network. This business model relies on Germany’s smart meter standards that ensure all market participants can access the data they require.

We currently find ourselves in a standoff. The regulator is waiting on companies to offer solar powered embedded networks that include retail competition, while companies are waiting on the regulator to create an accessible playing field that would make such services viable.

The recently released Finkel Report touches on this by recommending a “review of the regulation of individual power systems and microgrids”.

Stucco members celebrating signing the installation contract with Solaray. Monique Duggan Stucco’s bespoke solution

In the absence of such a solution, Stucco made a unique agreement with the regulator: the co-op committed to cover fully the costs of installing a grid meter for any unit whose occupant wishes to exit the embedded network in the future.

Such a commitment was feasible because Stucco’s residents, as co-op members, have direct input into the management of the network including controlling prices (that are mandated to be cheaper than any grid offer). But it is difficult to image regular strata committees accepting such liabilities.

Embedded networks are therefore not the best general solution for retrofitting solar on apartments, at least not under current regulations. This is unfortunate because they represent the best utilisation of an apartment block’s solar resource (Stucco’s system provides more than 75% of the building’s electricity) and are therefore increasingly being adopted by developers.

Advice for apartments

The good news for residents of existing apartments is that there are easier routes to installing solar. The even better news is that the cost of solar systems has plummeted (and continues to do so), while retail rates continue to skyrocket, so much so that body corporates are reporting rates of return of 15-20% on their solar investments.

The recommended options for apartments are epitomised by the old adage “keep it simple”. They fall into two categories: a single solar system to power the common area, or multiple smaller systems powering individual units. Which of these is best suited to a particular apartment depends primarily on the building’s size (as a proxy for its energy demand).

Decision tree for solar power on apartments. Bjorn Sturmberg

For buildings with 1 square metre of sunny roof space per 2m² of floor space (typically blocks up three stories high), it is worth installing a solar system for each unit, as these will typically be well matched to unit’s consumption.

Taller buildings (with less sunshine per apartment) are better off installing a single system for the common area, particularly if this contains power-hungry elements such as elevators or heating and cooling systems.

But here’s the crux: no apartment can install solar without the political support of its strata committee. While this hurdle has historically tripped up many initiatives, increased public awareness has created a groundswell of support. Plus you may need fewer votes than you think.

Myth of the Special Resolution. Christine Byrne - Green Strata

To improve the chances of overcoming this barrier I have put together a solar-powered apartment pitch deck, available here.

While this article focuses on solar, it is important to remember that the first priority for any building should be to improve energy efficiency, by installing items such as LED lights, modern appliances, and insulation and draft proofing. For advice on these opportunities see the City of Sydney’s Smart Green Apartments website and the Smart Blocks website.

Lastly, adding batteries to an apartment solar system creates extra challenges, for instance fire-prevention planning. But it allows for far greater energy independence and resilience, and a chance to join the future of distributed energy currently being enjoyed by so many of Australia’s non-strata householders.

Stucco Co-operative’s 43.2 kWh battery system. Bjorn Sturmberg

Bjorn Sturmberg is a founding director of SunTenants Pty Ltd and Kairos Power Pty Ltd. SunTenants is a social enterprise bringing the solar revolution to Australia's rentals (single occupancy, ie non-apartments) and was the basis on which Bjorn was awarded a 2017 Myer Innovation Fellowship. Kairos Power is a boutique engineering and research consultancy specialising in hybrid microgrids and energy markets.

Once the coat around the seed is moistened, the embryo cells expand and burst out in a process called germination. shutterstock/NUM LPPHOTO

This is an article from Curious Kids, a new series for children. The Conversation is asking kids to send in questions they’d like an expert to answer. All questions are welcome – serious, weird or wacky!

How can a tiny seed actually grow into a huge tree? – Finney, aged 6, from Bairnsdale in rural Victoria.

Tree seeds fall (like the tiny Eucalypt seeds) or helicopter down (like the winged seeds of the Maple) from their parents with a full set of instructions on how to grow.

A single tree may drop hundreds or even many thousands of seeds. Many of these seeds will become snacks for insects or fall where the ground is too hard, too dry, or just not suitable for trees. Some though will fall where the situation is just right!

Just right might mean bare dirt or some nice decayed mulch with enough sunlight.

The seed contains an embryo - a group of cells ready to form roots, a stem and the first leaves. Once the coat around the seed is moistened, the embryo cells expand and burst out in a process called germination.

Time-lapse of seed germination.

First, the roots will develop and push out and down into the soil to make sure the new plant can get water. Then the stem cells stretch up to display the first leaves.

The embryo uses food stored in the seed to power its initial growth until the leaves can start producing food. Small seeds don’t have much stored food so they have to fall in just the right spot to be successful. The parent tree has some ways to improve the chances of its seed finding the right spot, like dropping seeds after a bushfire has made the ground bare and free from other plants that would use all the water and nutrients.

For some plants, a bushfire triggers the release of seeds. Flickr/Tatters, CC BY

Once the roots are in the soil and the first leaves are in the sun, the plant is ready to really start growing.

People stop growing after they’ve become grown-ups but trees just keep getting taller and thicker however long they are alive.

Grass, bamboo and many other plants grow from the bottom up, so if you put a mark on the stem and come back in a little while, that mark will have been pushed further above the ground. But if you put a mark or even nail a board into a tree at one metre above the ground then come back in 10 years, it will still be only one metre above the ground. That’s because trees grow from the outside and the top up.

Some trees can grow to be more than 100 metres tall! Flickr/Andrew Malone, CC BY

The newest and outer shell of a tree contains all the living parts of the wood - the parts that move water up from the roots and food down from the leaves. If trees stop growing these outer, living shells of wood, the whole tree dies.

Some trees can grow to be more than 100 metres tall – that’s as tall as a skyscraper! In fact, humans are now building buildings out of wood that are over 50 metres tall and there are plans to go well beyond that.

The tallest tree currently is over 110 metres tall, and scientists think some trees may have been as much as 150 metres tall.

Trees grow from the top up.

A problem with getting even taller is that trees use water the same as you use blood - to move the nutrients and oxygen and other vital things around our body. But a tall tree has to move it from the roots to the tip of the leaves. For a 100 metre tall tree, that is like 30 flights of stairs. And a big tree could use more than 200 litres of water every day. Imagine carrying 30 buckets of water up 30 flights of stairs every day!

In our tall buildings, we need huge pumps and generators to move the water to the top, but trees just rely on their amazing structure and a little bit of power from the Sun.

Hello, curious kids! Have you got a question you’d like an expert to answer? Ask an adult to send your question to us. They can:

* Email your question to curiouskids@theconversation.edu.au
* Tell us on Twitter by tagging @ConversationEDU with the hashtag #curiouskids, or
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Please tell us your name, age, and which city you live in. You can send an audio recording of your question too, if you want. Send as many questions as you like! We won’t be able to answer every question but we will do our best.

Cris Brack 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.

A 'thinned' landscape, which provides far from ideal habitat for many species. Author provided

Land clearing is accelerating across eastern Australia, despite our new research providing a clear warning of its impacts on the Great Barrier Reef, regional and global climate, and threatened native wildlife.

Policies in place to control land clearing have been wound back across all Australian states, with major consequences for our natural environment.

One of the recent policy changes made in Queensland and New South Wales has been the introduction of self-assessable codes that allow landholders to clear native vegetation without a permit. These codes are meant to allow small amounts of “low-risk” clearing, so that landholders save time and money and government can focus on regulating activities that have bigger potential impacts on the environment.

However, substantial areas of native forest are set to be cleared in Queensland under the guise of vegetation “thinning”, which is allowed by these self-assessable codes. How did this happen?

Thin on the ground

Thinning involves the selective removal of native trees and shrubs, and is widely used in the grazing industry to improve pasture quality. It has been argued that thinning returns the environment back to its “natural state” and provides better habitat for native wildlife. However, the science supporting this practice is not as clear-cut as it seems.

Vegetation “thickening” is part of a natural, dynamic ecological cycle. Australia’s climate is highly variable, so vegetation tends to grow more in wetter years and then dies off during drought years. These natural cycles of thickening and thinning can span 50 years or more. In most areas of inland eastern Australia, there is little evidence for ongoing vegetation thickening since pastoral settlement.

Thinning of vegetation using tractors, blades and other machinery interrupts this natural cycle, which can make post-drought recovery of native vegetation more difficult. Loss of tree and shrub cover puts native wildlife at much greater risk from introduced predators like cats, and aggressive, “despotic” native birds. Thinning reduces the diversity of wildlife by favouring a few highly dominant species that prefer open vegetation, and reduces the availability of old trees with hollows.

Many native birds and animals can only survive in vegetation that hasn’t been cleared for at least 30 years. So although vegetation of course grows back after clearing, for native wildlife it’s a matter of quality, not just quantity.

Land clearing by stealth?

Thinning codes in Queensland and New South Wales allow landholders to clear vegetation that has thickened beyond its “natural state”. Yet there is little agreement on what the “natural state” is for many native vegetation communities.

Under the Queensland codes, up to 75% of vegetation in an area can be removed without a permit, and in New South Wales thinning can reduce tree density to a level that is too low to support natural ecosystems.

All of this thinning adds up. Since August 2016, the Queensland government has received self-assessable vegetation clearing code notifications totalling more than 260,000 hectares. These areas include habitat for threatened species, and ecosystems that have already been extensively cleared.

It may be that the actual amount of vegetation cleared under thinning codes is less than the notifications suggest. But we will only know for sure when the next report on land clearing is released, and by then it will be too late.

Getting the balance right

Vegetation policy needs to strike a balance between protecting the environment and enabling landholders to manage their businesses efficiently and sustainably. While self-regulation makes sense for some small-scale activities, the current thinning codes allow large areas of vegetation to be removed from high-risk areas without government oversight.

Thinning codes should only allow vegetation to be cleared in areas that are not mapped as habitat for threatened species or ecosystems, and not to an extent where only scattered trees are left standing in a landscape. Stronger regulation is still needed to reduce the rate of land clearing, which in Queensland is now the highest in a decade.

Protecting native vegetation on private land reduces soil erosion and soil salinity, improves water quality, regulates climate, and allows Australia’s unique plants and animals to survive. Landholders who preserve native vegetation alongside farming provide essential services to the Australian community, and should be rewarded. We need long-term incentives to allow landholders to profit from protecting vegetation instead of clearing it.

Our research has shown that Australian governments spend billions of dollars trying to achieve the benefits already provided by native vegetation, through programs such as the Emissions Reduction Fund, the 20 Million Trees program and Reef Rescue. Yet far more damage is inflicted by under-regulated clearing than is “fixed” by these programs.

Imagine what could be achieved if we spent that money more effectively.

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

Anita J Cosgrove receives funding from the Australian Research Council. She is a member of the Black-throated Finch Recovery Team, BirdLife Australia and the Australian Conservation Foundation.

Jennifer Lesley Silcock receives funding from the NESP Threatened Species Hub at the University of Queensland.

Leonie Seabrook receives funding from the Australian Research Council.

Megan C Evans receives funding from the National Environmental Research Programme Threatened Species Recovery Hub.