IPCC climate change report: Human role in global warming now even clearer
VIDEO: IPCC urges world to reduce greenhouse emissions(Lateline)
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.
Analysis: 5th IPCC report
- ABC Environment: Michael E Mann and Dana Nuccitelli write that climate scientists are increasingly confident humans are causing global warming.
- ABC Environment: When 97 per cent of climate scientists agree with 95 per cent certainty that climate change is caused by humans, you can be damn sure it is, writes Sara Phillips.
- The Drum: The ANU’s Professor Will Steffensays the report provides details that stamp out the myths and distortions of those trying to discredit climate science.
- Analysis: It may have all but been leaked in the months prior to today’s release, but this report is by far the most important from the IPCC, writes Sarah Clarke.
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.
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 sea level has risen and concentrations of greenhouse gases have increased.”
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.”
‘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.
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The Guardian’s summaries:
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