Australia — Climate change will increase the likelihood of deaths from heat stress and bushfires, and potentially place more than a quarter of a million Australian homes at risk from rising sea levels, according to a United Nations-backed draft document.
The leaked second-order draft document of the Intergovernmental Panel on Climate Change’s (IPCC) second working group examines impacts and vulnerabilities from global warming and details a grim outlook for Australia.
Climate change is expected to increase the number of days with very high and extreme fire weather, according to a copy of the document, posted on the Bishop Hill blog, a website sceptical about global warming. Fire management in Australia will become increasingly challenging, the report said.
We’ve built properties in areas that are too vulnerable to fire but we’ve done the same with sea-level, we’ve done the same with houses on flood plains, said Professor Andy Pitman, director of UNSW’s ARC Centre of Excellence for Climate System Science, commenting on the leaked report. We haven’t taken the Australian environment sufficiently into account where we’ve built.
The IPCC last month released the final draft of the first part of its Fifth Assessment, examining the science behind climate change projections. The second report, now leaked in draft form, is scheduled to be approved in Japan in late March 2014, with a third report detailing mitigation options released a couple of weeks later.
Many Australian researchers have contributed to the IPCC reports. Several on Monday noted the reports bring together already-published research, and the latest statements would be subject to further scrutiny before being signed off in Japan. The draft is dated 28 March, 2012.
The leaked document noted that a 1.1-metre rise in sea levels would put at risk some $226 billion in residential and commercial assets along Australia’s coasts. These include some 274,000 homes, according to a federal government report in 2011. Separate research from 2012 cited in the draft noted that significant coastal road and rail infrastructure would also be at risk from a sea-level increase of just half a metre.
In the recent IPCC report on climate science, the expected sea-leavel range was between 26 and 82 centimetres by the end of this century alone, with a 98-centimetre rise estimated as the worst-case scenario.
In recent years, sea levels have been creeping higher by about 3.2 millimetres annually, in part because the world’s oceans are heating up and expanding, and from melting glaciers.
Rising heat stress accompanying the expected increase in extremely hot days will also worsen. The draft report noted that the three days of extreme heat in south-eastern Australia ahead of the 2009 Black Saturday bushfires in Victoria saw reported heat-related health problems rise 34-fold, with people aged over 75 accounting for almost two-thirds of the total.
Cities such as Sydney will see heat-related deaths soar by the end of the century, the draft said, citing research from UK researcher Simon Gosling. Without adaptation, heat-related deaths could triple to 7.4 per 100,000 in 2070-99, from 2.5 in 1960-99, based on one scenario.
Mental health issues, water- and food-borne diseases will also increase under global warming projections.
Along with the fire and heat risks, floods may also worsen as a warming atmosphere holds more moisture, leading to more severe rain events. One study found that 50-year and 100-year flood peaks will rise 10-20 per cent by 2050, the draft document noted, citing evidence in Australia and New Zealand.