Indigenous Australians face “disproportionate” harm from climate change, according to a leaked report from the Intergovernmental Panel on Climate Change.
The second IPCC report, which is due to be released next March, also warns that climate change could swamp $226bn worth of coastal property via sea-level rises and cause the number of heatwave-related deaths in Sydney to triple by the end of the century.
It says there is “high agreement” among scientists that Indigenous people will face significant challenges from heat stress, extreme weather events and heightened rates of disease by 2100.
“Little adaptation of Indigenous communities to climate change is apparent to date,” the report says.
A sharp increase in heatwaves will impact the broader Australian population, especially older people, through heat-related deaths and hospitalisations. In Sydney, the number of deaths caused by heatwaves is expected to triple from 2.5 deaths for every 100,000 people to 7.4 deaths for every 100,000 people by 2100.
Water and food-borne diseases are projected to increase, with up to 870,000 new cases of bacterial gastroenteritis by 2100. But the IPCC warns there is minimal scientific consensus when it comes to specific disease projections and their link to climate change.
Australia is set to suffer financial as well as human loss, with the IPCC saying sea-level rise is a “significant risk” to the country because of the heavy population skew towards coastal cities and towns.
A rise of 1.1m would affect assets worth $226bn, according to the report, threatening 274,000 residential and 8,600 commercial buildings. Risks to road and rail infrastructure would “increase significantly” with a rise above 0.5m, the report indicates.
“While the magnitude of sea-level rise during the 21st century remains uncertain, its persistence over many centuries implies that realisation of these risks is only a question of time,” it says.
The leaking of the second IPCC report of three comes in the wake of the official release of the headline first report, which was unveiled in September. The initial document, a summation of the work of hundreds of climate scientists from around the world over the past five years, said there was a 95% certainty that humans are responsible for most of the 0.89C rise in average temperatures since 1901.
Australia is set to experience a 6C rise in average temperatures on its hottest days, with the loss of many reptile, bird and mammal species, as well as the celebrated Kakadu wetlands.
Separate research published this week by Australian scientists shows that the impact of el Niño years will be exacerbated by climate change. El Niño is a periodic climate condition which causes warming of the ocean and shifting rainfall patterns in parts of the Pacific region. It can help drive extremely warm years, such as in 1998.
The study team found that areas in the western Pacific, such as eastern Australia, will experience worse droughts during el Niño years.
Scott Power of the Bureau of Meteorology, the lead author of the report, said: “Projections produced by the models indicate that global warming interferes with the impact that el Niño sea-surface temperature patterns have on rainfall. This interference causes an intensification of el Niño-driven drying in the western Pacific and rainfall increases in the central and eastern equatorial Pacific.”
Dr Wenju Cai of the CSIRO added: “During el Niño, western Pacific countries – Australasia, including Australia – experience unusually low rainfall, while the eastern equatorial Pacific receives more rainfall than usual.
“This study finds that both the wet and dry anomalies will be greater in future el Niño years. This means that [el Niño]-induced drought and floods will be more intense in the future.”