The world’s climate scientists and governments have declared climate change is now a threat to human wellbeing and warned we are about to miss the window to “secure a liveable and sustainable future for all”.
The finding comes in the latest Intergovernmental Panel on Climate Change (IPCC) report on the impacts of climate change and how we can adapt to them.
The new report found the scale of the impacts from climate change threatened to overwhelm Australia's — and the world's — ability to adapt in the coming decades, with some impacts requiring rapid and radical transformations in how we live and operate, combined with immediate and sharp cuts to greenhouse gas emissions.
Immediate actions aimed at stopping warming at 1.5 degrees Celsius could reduce many of the most severe impacts to society and ecosystems, but will not stop all of them.
Current global policies put the world on a course of at least 2.1C warming by 2100, and possibly as much as 3.9C.
Regardless of our actions now, the report says regional and urban areas will face irreversible changes that will impact millions of people's lives, including:
- Sea level rises that will destroy and displace homes and infrastructure
- Heat that will kill more people each year
- Hanged weather patterns that will lower the productivity of both crop farming and livestock in many areas
"The scientific evidence is unequivocal: Climate change is a threat to human wellbeing and the health of the planet," IPCC Working Group II co-chair Hans-Otto Pörtner said.
The report urges urgent action to adapt to the changes we will see, as well as cuts to greenhouse gas emissions.
Those urgent adaptation actions include improving low-income houses to cope with heat, changing planning regulations to stop dangerous development, and planning for the closure of some industries.
The report advises we must address inequality between rich and poor, which it says exacerbates vulnerability to climate change and undermines our capacity to adapt.
"What's clear is that climate change already is impacting on the poorest and most disadvantaged people across the globe disproportionately. And those projections are expected to continue," said one of the report's authors, Mark Howden from the ANU.
The report also said the time for incremental adaptations was past, and we now needed "transformational" changes.
For example, instead of protecting houses from rising sea levels, some may need to be abandoned or rebuilt on higher ground. Some sectors, such as snow tourism in Australia, may need to prepare for closure altogether.
"This abdication of leadership is criminal. The world's biggest polluters are guilty of arson of our only home."
Delaying not an option, IPCC says
The emissions reduction policies of Australia and the rest of the world would leave many human and natural systems beyond adaptation limits, the report said.
But it said many of the most devastating impacts were still avoidable by simultaneously implementing transformational adaptation and drastically cutting emissions.
"It is essential to meet the goal of limiting [the] global temperature rise to 1.5C. And science tells us that will require the world to cut emissions by 45 per cent by 2030 and achieve net zero emissions by 2050," Mr Guterres said.
"But according to current commitments, global emissions are set to increase almost 14 per cent over the current decade."
"I know people everywhere are anxious and angry," Mr Guterres said. "I am too. Now is the time to turn rage into action."
The report is the second of three being produced by the IPCC in its sixth assessment round (AR6).
It was written by 270 authors and synthesises more than 34,000 pieces of scientific research. And it is approved by 195 governments.
The first report, released in August last year, analysed the physical basis for climate change, and was labelled a "code red for humanity".
Report says government failing to address inevitable sea level rises
The report criticises Australia's federal government, as well as state governments, for an "absence" of clear guidance, "rendering Australia unprepared for flooding from sea-level rise".
Those impacts are set to be significant for Australia, since about 85 per cent of Australians live within 50km of the coast.
The report found if the sea level rose by 1.1m — which could happen early in the next century — up to a quarter of a million residential buildings would be exposed to inundation as well as thousands more commercial and industrial buildings.
Between $164 billion and $226 billion of infrastructure would be exposed, along with up to 35,000km of roads and 1,500km of rail lines.
It notes protecting shorelines will become increasingly expensive and, in some cases, impossible.
In some places, "managed retreat" from coastlines may be the best option, the report says.
Extreme heat to kill hundreds more in Australian cities
With 90 per cent of Australians living in cities, the report notes Australia is particularly vulnerable to the urban impacts of climate change.
If greenhouse gas emissions continue to be high, the number of days each year with temperatures over 35C will increase by up to 350 per cent — and by at least 80 per cent — by 2090.
However, if emissions are reduced quickly, those extreme-heat days could increase by only 25-80 per cent by 2090.
With just 2C of warming, unprecedented extreme temperatures as high as 50C are likely to be seen in Sydney and Melbourne.
If emissions continue to remain high, the number of deaths could rise to 600 every year in Melbourne, Sydney and Brisbane between 2031 and 2080, compared to a historical figure of about 142.
But if emissions are rapidly reduced, that could be reduced to about 300 per year, saving thousands of Australian lives.
The report notes that the impacts of urban heat disproportionately affect those with low incomes.
It notes that air conditioning reduces mortality during heat waves by about 80 per cent, but that those in poor-quality housing and the homeless are particularly vulnerable.
It said planning decisions needed to keep more space between houses, result in more trees being planted and encourage the use of reflective building materials, all of which could significantly reduce urban heat as well as reduce the reliance on electricity, thereby reducing the risks of blackouts.
Food production already hit and it is going to get tougher
Agriculture has already copped significant disruption from climate change in Australia and that is set to get worse.
In some parts of Australia wheat yields are expected to decline by up to 30 per cent by 2050 and extreme weather will lower milk production and livestock reproduction.
The report said while the sector was slowly changing, it would require radical "transformative" adaptation to cope with the physical impacts of climate change, and also because of the necessary role the sector would play in reducing greenhouse gas emissions.
But the report noted the ability of agriculture to make the required adaptations could be undermined by financial limitations and insurers abandoning parts of the increasingly high-risk sector.
“Without a major turnaround in carbon emissions and the way we farm, we are likely to see mass crop failures and food system collapse — with people in poverty hit first and hardest by a crisis they did not cause,” Olivier De Schutter, chair of the international panel of experts on sustainable food systems, said.
"Transforming agriculture is now urgent, governments must act to support local communities' efforts to feed themselves and encourage resilience through diversity, not uniformity."
Some natural ecosystems likely to collapse
While the report has an intense focus on adaptation, it says there is little we can do to help coral reefs adapt, meaning ecosystems like the Great Barrier Reef look set to face devastating consequences.
In 2016, the worst coral-bleaching event on record occurred on the Great Barrier Reef, with over 90 per cent of reefs affected.
The report said that would get worse no matter what we did, with bleaching conditions projected to occur every five years from 2035, after which time the frequency would depend on how quickly we reined in emissions.
If emissions remained high, bleaching could occur every year from 2044. If we reduced emissions more quickly, it could take a further six years before those conditions were seen yearly on the Great Barrier Reef.
Unfortunately, the direct impacts of heat would likely be compounded by other climate change impacts. Cyclone intensity would increase, which would “greatly accelerate coral reef degradation,” the report said.
Heavier downpours will wash more sediment and pollution into the water from the coast, which will compound the damage, as well as boost the population of coral-eating crown of thorns starfish.
The report noted the Australian government's investment of $1.9 billion in the reef, but said adaptation measures aimed at climate impacts might only slow the damage and would "not prevent widespread bleaching".
Some other ecosystems are in nearly as perilous a position, including alpine ash forests, mangroves and marine kelp forests.
Multiple climate impacts will compound, amplify
The report highlights the "compounding" impacts of climate change, and how impacts in one sector can "cascade" into other sectors.
Compounding impacts are when multiple events happen at the same time, and each amplifies the effects of the other.
"One example would be the combination of more intense cyclones and sea level rise," Professor Howden said.
"When a cyclone comes in against the coast, often it pushes water up ahead of it and rises the water underneath it, and you get a storm surge that causes coastal flooding and damage.
"Now, if you've got sea level rise, that actually means you increase the amount of damage for any given cyclone strength."
An example of cascading impacts was the Black Summer bushfires, which were exacerbated by climate change, and had multiple effects through disparate systems including threatened species, housing, health, finance and tourism.
The report said these sorts of cascading and compounding impacts "require new, larger-scale and timely adaptation".
In particular, the report highlights the need for "climate-resilient development", which involves reducing inequalities in society.
Economic impacts are within our control
The report indicated Australia could lose 6 per cent of its GDP by 2070 under 3C of warming, while a 2.6 per cent rise in GDP was possible for a 1.5C scenario.
It cited a CSIRO study, which found real wages would be halved by 2060 unless we addressed emissions and adaptation.
Responsibility for adapting to climate change falls to all levels of government, all industries and individuals.
So analysing how good Australia had been at adapting was complex, Professor Howden said.
But Australia’s federal government has been criticised for not taking adaptation seriously enough.
In 2019, the ABC revealed documents showing Australia’s top government bureaucrats believed Australia was not adequately prepared for the impact of climate change, which could impact "the full spectrum of human activity" and was already "overwhelming" the country's ability to respond.
A group of Australia’s most senior bureaucrats, called "Project Climate Ready", was set up in 2017 when Malcolm Turnbull was prime minister, but was abandoned in 2018.
Richie Merzian, from the Australia Institute, said Australia had never undertaken a national climate risk assessment, despite the UN requesting such documents be produced.
"It's unbelievable and irresponsible that after all the devastating fires, floods and droughts, the federal government has never undertaken a national risk assessment to better understand and prepare for climate change impacts," Mr Merzian said.
A spokesman for the federal government said the government was making unprecedented investments in climate adaptation and resilience and was working internationally to reduce emissions.
