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IPCC report warns greenhouse gas levels at highest point in 800,000 years, identifies fossil fuels as cause of recent increases
Updated
The world’s top scientists have given their clearest warning yet of the severe and irreversible impacts of climate change.
The United Nations Intergovernmental Panel on Climate Change (IPCC) has released its synthesis report, a summary of its last three reports.
It warns greenhouse gas levels are at their highest point in 800,000 years, with recent increases mostly due to the burning of fossil fuels.
“Continued emission of greenhouse gases will cause further warming and long-lasting changes in all components of the climate system, increasing the likelihood of severe, pervasive and irreversible impacts for people and ecosystems,” the report said.
“Limiting climate change would require substantial and sustained reductions in greenhouse gas emissions which, together with adaptation, can limit climate change risks.”
One of the authors, Professor Jim Skea, said the document would be invaluable in future climate change negotiations.
“The statements are much more powerful because they’re put together,” he said.
“The inferences that you can draw are just very obvious for policymakers now and I think that’s what the achievement is.”
Leaders must act, UN chief warns
UN secretary-general Ban Ki-moon said the report was the most comprehensive appraisal of climate change yet and that human influence was clear.
“Science has spoken, there is no ambiguity in their message,” he said.
“The report found that the world is largely very ill-prepared for the risk of changing climate, especially the poor and most vulnerable, who have contributed least to this problem.
“Leaders must act. Time is not on our side.”
Australian oceans expert John Church was in Copenhagen to negotiate the final wording of the report.
Dr Church was the coordinating lead author of the sea levels chapter and said warming of the climate system is “unequivocal”.
“There’s many components – increasing surface temperature, melting glaciers, increasing ocean heat content, ice sheets losing mass, sea level rising,” he said.
“It’s very clear that there’s a human component that’s contributed significantly to that with rising impacts across many regions.”
The document will be an invaluable summary for climate negotiations for emission reduction targets post-2020.
Governments will meet in Peru this year as part of the United Nations Framework Convention on Climate Change annual meeting.
Targets are expected to be finalised at the 2015 negotiations in Paris, but the Peru conference will serve as an important step forward in setting the framework.