IPCC climate change report: Human role in global warming now even clearer
Updated Sat 28 Sep 2013, 3:50pm AEST
The Intergovernmental Panel on Climate Change (IPCC) says there is now a 95 per cent probability that humans are responsible for global warming.
The figure, in the IPCC’s Fifth Assessment Report, which was released in Stockholm on Friday, is a 5 per cent increase from the panel’s 2007 landmark report.
More than 600 scientists and researchers contributed to the fifth assessment report, which is the result of almost seven years’ work by scientists and policymakers.
It is based on more than 50,000 contributions from around the world, and an exhaustive peer review process.
Government representatives from member nations haggled with the panel’s scientists long into the night over the precise wording of the report.
The report summary says the concentration of carbon dioxide in the atmosphere has risen by 40 per cent since the pre-industrial era.
The report presents a number of different scenarios of how climate change may unfold over the next century.
The majority of the modelling points to a global mean sea-level rise of between 26 and 82 centimetres by 2100.
The worst case scenario is for a sea level rise of 98cm.
The majority of climate models point to a mean temperature rise of around 2 degrees Celsius. The smallest predicted temperature rise is 0.3C and the largest rise is 4.8C.
“Many of the observed changes are unprecedented over decades to millennia,” IPCC chairperson Rajendra Pachauri said.
“The atmosphere and ocean have warmed. The amounts of snow and ice have diminished.
“The sea level has risen and concentrations of greenhouse gases have increased.”
Hunt says Coalition accepts IPCC findings
Federal Minister for the Environment Greg Hunt told Saturday AM that the Coalition accepts the scientific assessment published in the report.
“I’ve spoken, of course, with the scientific advisory group that informs the Australian Government, which is the Bureau of Meteorology, the CSIRO, and the Antarctic Division from within the Environment Department, and they confirm that they are in general agreement with the findings of the IPCC report,” he said.
Mr Hunt says the report outlined a range of scenarios including increasing temperatures and rising sea levels.
“There are a range of scenarios in the report, and the broad range shows that temperatures are likely to change over the coming century from between 0.9 to 5.4 degrees,” he said.
What does this mean? It means that we need to do practical things that actually reduce emissions.
Federal Minister for the Environment Greg Hunt
“Now that depends on the extent to which the world reduces emissions, but that’s the range set out.
“What we’ve seen since 1901 is a 19 centimetre rise, and a range again for the coming century of between 0.28 metres – or 28 centimetres – and 98 centimetres.
“What does this mean? It means that we need to do practical things that actually reduce emissions.”
Mr Hunt identified three areas in which practical action needs to be taken to counter climate change.
“One is taking steps to reduce our domestic emissions. Two, making sure that … we have a national plan for adaptation,” he said.
“And the third thing is, at the global level – because this issue can only be resolved at the global level – we want to work with China and the United States, India and the [European Union] on the essence of an international agreement.”
‘The heat is on’, act now, Ban Ki-moon says
UN secretary-general Ban Ki-moon says the study is a call for governments, many of which have been focused on spurring weak economies rather than fighting climate change, to work to reach a planned UN accord in 2015 to combat global warming.
“The heat is on. Now we must act,” he said.
In a statement, Environment Minister Greg Hunt welcomed the report and reaffirmed the Government’s commitment to meeting Australia’s 2020 emissions reduction target.
US secretary of state John Kerry says the report is a wake-up call.
“Those who deny the science or choose excuses over action are playing with fire,” he said, referring to sceptics who question the need for urgent action.
Professor Andy Pitman from the University of NSW says the report’s seven-year cycle is “incredibly onerous” and probably unprecedented in any scientific field.
“I actually think it’s too slow to respond to emerging issues within climate science,” Professor Pitman said.
The IPCC has shown it can fast track its work: a 2011 report on managing extreme weather and disasters was produced relatively quickly, an approach that Professor Pitman favours.
“That model might be one that we need to interweave with a cycle of IPCC reports,” he said.
“I would be quite happy if they became once-a-decade, interspersed with fast response reports on particular [topics].”
As expected, the fifth IPCC report shows the concentration of carbon dioxide in the atmosphere has increased by more than 20 per cent since the 1950s.
Global temperatures have risen almost 1C since the pre-industrial era.
The IPCC assessment is considered a relatively conservative estimate of the threat posed by global warming.
The IPCC was established by the UN Environment Program and the World Meteorological Organisation in 1988 in order to review and report on the published climate science.
We’re doing everything humanly possible to see that the report is of very high quality, totally credible and robust in every sense of the scientific content.
IPCC chairperson Rajendra Pachauri
The IPCC’s previous report six years ago was criticised for a handful of well-publicised mistakes, particularly the claim that Himalayan glaciers would disappear by 2035.
However, Dr Pachauri says the latest findings are solid.
“Of course we’ve learnt from that experience and this time around we’re being very, very careful,” he said.
“Of course this is a human effort but we’re doing everything humanly possible to see that the report is of very high quality, totally credible and robust in every sense of the scientific content.”