This is not a warning but a dire wake-up call. Current changes across the continent, and their potential outcomes, pose an existential threat to our survival. But there are actions we can take to help protect or restore ecosystems.

In 1992, 1,700 scientistswarnedthat human beings and the natural world were on a collision course. Seventeen years later, scientists describedplanetary boundarieswithin which humans and other life could have a safe space to operate. These are environmental thresholds, such as the amount of carbon dioxide in the atmosphere and changes in land use.

Crossing such boundaries was considered a risk that would cause environmental changes so profound, they genuinely posed anexistential threat to humanity.

This grave reality is what our major research paperconfronts.

In what may be the most comprehensive evaluation of the environmental state of play in Australia, we show major and iconic ecosystems are collapsing across the continent and into Antarctica. These systems sustain life, and evidence of their demise shows were exceeding planetary boundaries.

We found 19 Australian ecosystems met our criteria to be classified as collapsing. This includes the arid interior,savannasandmangrovesof northern Australia, theGreat Barrier Reef,Shark Bay, southern Australiaskelpandalpine ashforests, tundra on Macquarie Island, andmoss beds in Antarctica.

We define collapse as the state where ecosystems have changed in a substantial, negative way from their original state such as species or habitat loss, or reduced vegetation or coral cover and are unlikely to recover.

The good and bad news

Ecosystems consist of living and non-living components, and their interactions. They work like a super-complex engine: when some components are removed or stop working, knock-on consequences can lead to system failure.

Our study is based on measured data and observations, not modelling or predictions for the future. Encouragingly, not all ecosystems we examined have collapsed across their entire range. We still have, for instance, some intact reefs on the Great Barrier Reef, especially in deeper waters. And northern Australia has some of the most intact and least-modified stretches of savanna woodlands on Earth.

Still, collapses are happening, including in regions critical for growing food. This includes theMurray-Darling Basin, which covers about 14% of Australias landmass. Its rivers and other freshwater systems support more than 30% of Australias foodproduction.

The effects of floods, fires, heatwaves and storms do not stop at farm gates; theyre felt equally in agricultural areas and natural ecosystems. We shouldnt forget how towns ran out ofdrinking waterduring the recent drought.

Drinking water is also at risk when ecosystems collapse in our water catchments. In Victoria, for example, the degradation of giantMountain Ash forests greatly reduces the amount of water flowing through the Thompson catchment, threatening the drinking water of nearly five million people in Melbourne.

This is a dire_wake-up_call not just a_warning_. Put bluntly, current changes across the continent, and their potential outcomes, pose an existential threat to our survival, and other life we share environments with.

In investigating patterns of collapse, we found most ecosystems experience multiple, concurrent pressures from both global climate change and regional human impacts (such as land clearing). Pressures are oftenadditive and extreme.

Take the last 11 years in Western Australia as an example.In the summer of 2010 and 2011, aheatwavespanning more than 300,000 square kilometres ravaged both marine and land ecosystems. The extreme heat devastated forests and woodlands, kelp forests, seagrass meadows and coral reefs. This catastrophe was followed by two cyclones.

A record-breaking, marine heatwave in late 2019 dealt a further blow. And another marine heatwave is predicted forthis April.

What to do about it?

Our brains trust comprises 38 experts from 21 universities, CSIRO and the federal Department of Agriculture Water and Environment. Beyond quantifying and reporting more doom and gloom, we asked the question: what can be done?

We devised a simple but tractable scheme called the 3As:

• Awarenessof what is important
• Anticipationof what is coming down the line
• Actionto stop the pressures or deal with impacts.

In our paper, we identify actions to help protect or restore ecosystems. Many are already happening. In some cases, ecosystems might be better left to recover by themselves, such as coral after a cyclone.

In other cases, active human intervention will be required for example, placing artificial nesting boxes for Carnabys black cockatoos in areas where old trees have beenremoved.

Future-ready actions are also vital. This includes reinstatingcultural burning practices, which havemultiple values and benefits for Aboriginal communitiesand can help minimise the risk and strength of bushfires.

It might also include replanting banks along the Murray River with species better suited towarmer conditions.

Some actions may be small and localised, but have substantial positive benefits.

For example, billions of migrating Bogong moths, the main summer food for critically endangered mountain pygmy possums, have not arrived in their typical numbers in Australian alpine regions in recent years. This was further exacerbated by the2019-20fires. Brilliantly,Zoos Victoriaanticipated this pressure and developed supplementary food Bogong bikkies.

Other more challenging, global or large-scale actions must address theroot cause of environmental threats, such ashuman population growth and per-capita consumptionof environmental resources.

We must rapidly reduce greenhouse gas emissions to net-zero, remove or suppress invasive species such asferal catsandbuffel grass, and stop widespreadland clearingand other forms of habitat destruction.

Our lives depend on it

The multiple ecosystem collapses we have documented in Australia are a harbinger forenvironments globally.The simplicity of the 3As is to show people_can_do something positive, either at the local level of a landcare group, or at the level of government departments and conservation agencies.

Our lives and those of ourchildren, as well as oureconomies, societies andcultures, depend on it.

We simply cannot afford any further delay.

This article, republished from The Conversation, was written by: Dana M Bergstrom, Principal Research Scientist, University of Wollongong Euan Ritchie, Professor in Wildlife Ecology and Conservation, Centre for Integrative Ecology, School of Life & Environmental Sciences, Deakin University Lesley Hughes, Professor, Department of Biological Sciences, Macquarie University Michael Depledge, Professor and Chair, Environment and Human Health, University of Exeter