GENEVA The world can still cap global warming at far lower levels than widely expected if nations "bite the bullet" and slash greenhouse gas emissions, the chairman of the U.N. climate panel says.
Rajendra Pachauri told Reuters that an appeal last month by the world's poorest nations and small island states to cap global warming at a 1.5 degrees Celsius (2.7 F) temperature rise over pre-industrial times should be taken "very seriously."
"I don't think it's beyond human capability to achieve," he said in an interview for a Reuters Global Climate and Alternative Energy Summit on September 8-10.
"But we'd have to prepared to bite the bullet ... It would require major efforts," he said. Pachauri's Intergovernmental Panel on Climate Change (IPCC) shared the 2007 Nobel Peace Prize with former U.S. vice president Al Gore.
A 1.5 Celsius target is far more ambitious than a 2 Celsius rise set by the Group of Eight industrialized nations and major economies such as China and India at a summit in Italy in July. Many climate experts say warming is already set to exceed 2 C.
"If a sizeable part of the global community ... feels that you have to stabilize at 1.5 degrees, we have to take that very, very seriously," Pachauri said during a world climate conference in Geneva.
The least developed nations such as Angola or Yemen and small island states including Barbados and Tuvalu total about 80 countries.
Beyond 1.5 Celsius, they argue that rising sea levels could wipe low-lying atolls off the map and that droughts, floods and heatwaves could have dangerous impacts for the poorest people in Africa, Asia and Latin America.
To achieve the goal of 1.5 degrees C, they demanded that rich nations cut greenhouse gas emissions by 45 percent below 1990 levels by 2020 as part of a new U.N. pact to fight global warming, due to be agreed in Copenhagen in December.
That is far deeper than current offers by recession-hit industrialized nations. Global temperatures have already risen by 0.7 Celsius since large-scale burning of fossil fuels began with the Industrial Revolution.
He said the IPCC, grouping thousands of experts, would look at ways of achieving lower global emissions in future reports.
He also said the world should give President Barack Obama leeway in working out a new U.N. climate treaty, recognizing that the United States cannot slash greenhouse gas emissions easily.
Obama wants to cut U.S. greenhouse gas emissions back to 1990 levels by 2020, a 14 percent cut from 2007 levels. Pachauri said that was "a step forward" from the presidency of George W. Bush, who foresaw a peak for U.S. emissions only in 2025.
"The world will have to provide some degree of latitude to the U.S. to see what further actions can be taken," he said. U.S. Senate Democrats on Monday announced a new delay to climate change legislation until later this month.
Pachauri criticized the G8 for acknowledging a 2 Celsius goal at a summit in Italy without setting 2020 goals for emissions cuts to help stay below the ceiling.
"The G8 has to come up with some firm commitments on reductions by 2020. They've missed out on that," he said.