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Global warming may have “abrupt and irreversible” consequences and could cause the extinction of almost a third of all plant and animal species on the planet, the UN’s climate science panel will say today.

The Intergovernmental Panel on Climate Change (IPCC), which shared this year’s Nobel Peace Prize with Al Gore, the former US Vice-President, will tell world leaders that they have only a decade to curb greenhouse gas emissions and prevent catastrophic warming.

The UN panel of 2,500 scientists is issuing its warning as governments prepare for a crucial climate summit in Bali next month. The report could shape environmental policy for decades.

A short summary for policymakers, to be used at the Bali conference, was agreed at 7am yesterday after all-night negotiations in Valencia. “Warming of the climate system is unequivocal,” the summary begins.

The agreed text states that human activities “could lead to abrupt or irreversible climate changes and impacts”. The report will note, however, that a range of policies, such as a carbon tax, emissions trading and incentives, could limit CO2 emissions but it does not recommend a particular approach, participants said.

A fuller document was still being agreed line by line last night by more than 140 delegations. The final version will be published this morning at a press conference chaired by Ban Ki Moon, the UN Secretary-General.

The report will say: “Approximately 20-30 per cent of plant and animal species assessed so far are likely to be at increased risk of extinction if global average temperatures exceed 1.5C to 2.5 C above 1980-99 levels.”

The “abrupt and irreversible” consequences of global warming could include the melting of the Greenland ice sheet, it will say. Other reasons for concern include melting of the polar ice-caps, widespread coral death, and the threat to indigenous people on small islands and in the Arctic region.

Environmental and science groups said that the report would ensure that the Bali discussions were firmly grounded in the scientific consensus on climate change. The talks are aimed at establishing a successor to the Kyoto Protocol on greenhouse emissions, which expires in 2012.

The WWF conservation group praised the IPCC’s scientists, who will receive the Nobel Peace Prize on December 10 in the middle of the Bali summit, for resisting pressure from governments seeking to weaken the report.

“The hard fact is we have caused climate change, and it’s also clear that we hold in our hands the solution to stop global warming,” Hans Verolme, a WWF expert on climate change, said. “The IPCC shows that to avoid irreparable harm, nothing less than deep cuts in carbon pollution are needed — the UN Climate Change conference in Bali will be where political leaders must act decisively.”

The IPCC’s “synthesis report” summarises three longer documents that together cover almost 3,000 pages, which predicted that temperatures are likely to rise by up to 4C by the end of the century, causing water shortages, more extreme weather, and the extinction of threatened species.

Today’s document ends a six-year review of the scientific evidence on climate change. The report will underline that predictions made by the panel six years ago are already coming true. But the IPCC has considered only work published up to last year, and so has ignored several alarming recent studies, such as research that suggests that the Southern Ocean and rainforests are soaking up less carbon dioxide than before.

— Government funding for recycling, energy saving, carbon emissions and nature protection is to be slashed by £300 million in emergency cuts, according to reports last night. The Department for the Environment, Food and Rural Affairs needs to make the savings after unexpected spending on tackling the foot-and-mouth outbreak.

World threat

2.5C a temperature rise of between 1.5C2.5C would threaten nearly a third of animal and plant species, according to the IPCC

4C a temperature rise this high would cause “significant extinctions”

Source: IPCC

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