Australia To Cop 'Once-In-A-Century' Flooding Every Year, Dire New Climate Report Warns

Some climate change effects are already "locked in", a terrifying new climate report has warned, forecasting devastating floods every year for Australia's coastal residents from 2050.

With the eyes of the world on school strikes, Greta Thunberg and the United Nations special summit in New York, the Intergovernmental Panel on Climate Change has dropped another hammer.

“Australia’s coastal cities and communities can expect to experience what was previously a once-in-a-century extreme coastal flooding event at least once every year by the middle of this century – in many cases much more frequently," said Associate Professor Nerilie Abram, Australian National University climate change scientist and a lead author of the report.

"We have no time to lose," added Professor Mark Howden, ANU Climate Change Institute Director and vice-chair of the IPCC.

Sea levels are expected to rise by between 60 centimetres and 1.1 metres by 2100, under a worst-case scenario. The best case scenario is between 30 and 60 cm, but only if emissions are drastically reduced and temperature increases limited.

Huge floods may become far more regular in Australia. Photo: Getty

The IPCC's Special Report on the Ocean and Cryosphere in a Changing Climate was released on Wednesday night (AEST) and spells out forecasts of catastrophe for Australia.

The report was released just hours after Prime Minister Scott Morrison derided climate campaigners like Greta Thunberg for raising "needless anxiety" about the state of the environment.

READ MORE: No, Prime Minister, Greta Thunberg's Climate Anxiety Is NOT 'Needless'

READ MORE: 'I Should Not Have To Be Here Today': Year 12 Students Skip Graduation To Attend Climate Strike

"Girt by sea, Australia faces serious climate challenge," states an accompanying comment piece from Abram and Howden, citing a "grim" future. Climate change's effects -- long-known -- are detailed as including heating up and acidifying oceans, melting ice sheets, and rising seas.

Data from the IPCC report

"Changes to oceans and ice around the world affect each and every Australian," said the report excerpt, written by Abram and Howden.

"If we allow climate change to continue at the current rate, Earth’s ocean and ice will respond in ways that become increasingly dangerous and threaten our way of life. On the other hand, if we take quick action to drastically reduce our greenhouse gas emissions then we can still reduce the risks that our people, food, economy and unique ecosystems will face in the future."

READ MORE: Climate Change Making Parents Feel Guilty For Having Kids

READ MORE: World's Worst Climate Disasters Cost $63 Billion In 2018

The ocean covers some 71 percent of the planet and contains 97 percent of the world's water, with ice sheets and glaciers covering 10 percent of the Earth. The report's authors say it is "very likely" that warming oceans can be "attributed to anthropogenic forcing" -- outlining that marine heatwaves have "doubled in frequency and have become longer-lasting, more intense and more extensive" between 1982 and 2016.

"The ocean is projected to transition to unprecedented conditions with increased temperatures, greater upper ocean stratification, further acidification, oxygen decline, and altered net primary production," the report forecasts.

"Marine heatwaves and extreme El Niño and La Niña events are projected to become more frequent."

Photo: Getty

The open ocean has lost as much as 3.3 percent of its oxygen, which has effects on marine plant and animal life.

READ MORE: Is A Failure To Act On Climate Change A Violation Of Human Rights?

READ MORE: How The Climate Change 'Health Emergency' Will Kill Us Faster

"Global mean sea level is rising, with acceleration in recent decades due to increasing rates of ice loss from the Greenland and Antarctic ice sheets, as well as continued glacier mass loss and ocean thermal expansion," the report said, also warning of more cyclones, rainfall and extreme waves.

"Nearly 50 percent of coastal wetlands have been lost over the last 100 years, as a result of the combined effects of localised human pressures, sea level rise, warming and extreme climate events."

The effects of climate change on oceans and flooding have been laid bare. Photo: Getty

Another Australian scientist working on the report -- Professor Andrew Mackintosh, head of Monash University's School of Earth, Atmosphere and Environment -- said the time was past for climate research to be debated.

“It’s not a matter of ‘believing’ in the science - science is underpinned by data and rigorous experiments. The results are there for everybody to see, not ‘believing’ in them is irresponsible," he said in a statement.

READ MORE: Sir David Attenborough Slams Australia On Climate Change

READ MORE: 1200 Businesses Give Workers Time Off To Attend Climate Strike

Howden and Abram detail that a combination of sea level rise, extreme winds and waves, storm surges and flooding from tropical cyclones may lead to yearly flooding events which would normally be described as "once in a century" disasters.

Ice is shrinking, scientists have warned. Photo: Getty

Howden told 10 daily that some areas would see a "10,000-fold or even a 100,000-fold increase" in such extreme weather.

"It's already happening, very significantly. There's a shrinking of ice, glaciers and ice sheets are shrinking by two-thirds of a trillion tonnes a year," he said.

"Last year, sea levels rose 3.6 millimetres, and it's accelerating... some places will see these 'one in a hundred year' events every few days at high tide."

Globally, the report warned "extreme sea level events that are historically rare (once per century in the recent past) are projected to occur frequently (at least once per year) at many locations by 2050... especially in tropical regions."

Besides direct human impacts, climate change could also irreversibly damage marine ecosystems, coral reefs and kelp forests to the point that fishing potential will decline by more than 20 percent by 2011.

Data from the IPCC report

"But by drastically reducing greenhouse gas emissions, we could buy ourselves more than a decade of extra time to prepare our coastal infrastructure against these damaging events – or even avoid them significantly," the authors said.

"The more decisively we act, the more we will be able to slow the speed and magnitude of future changes including to our ocean and ice. All of us can be part of achieving this, from our highest political representatives to individuals, households, local communities and businesses."

"The report serves as a wake-up call to the world about the devastating consequences of failing to act to address climate change. We have no time to lose."