Act fast on global warming, or extract CO2 from air: UN

New study says shift to low-carbon energy use is affordable

berlin — Faster action is needed to keep global warming to agreed limits and delays until 2030 could force reliance on technologies to extract greenhouse gases from the air, a UN report said on Sunday.

The study, drawing on the work of more than 1,000 experts, said a shift from fossil fuels to low-carbon energy such as wind, solar or nuclear power was affordable and would shave only about 0.06 percentage point a year off world economic growth.

“We have a window of opportunity for the next decade, and maximum the next two decades” to act at moderate costs, said Ottmar Edenhofer, co-chair of a Berlin meeting of the Intergovernmental Panel on Climate Change (IPCC). “I’m not saying it’s costless. I’m not say- ing climate policy is a free lunch. But it’s a lunch worthwhile to buy,” he said. The report, endorsed by governments, is meant as the main scientific guide for nations working on a UN deal to be agreed in late 2015 to rein in world greenhouse gas emissions that have hit repeated highs, led by China’s industrial growth.

Governments have promised to limit temperature rises to a maximum 2 degrees Celsius above pre-industrial times to avert ever more heat waves, floods, droughts and rising sea levels that the IPCC says are linked to man-made warming.

IPCC scenarios showed that world emissions of greenhouse gases would need to peak soon and tumble by between 40 and 70 per cent from 2010 levels by 2050, and then close to zero by 2100, to keep temperatures below 2C.

Such cuts are far deeper than most governments are planning.

“Ambitious mitigation may even require removing carbon dioxide from the atmosphere,” the IPCC said. Delay in acting to cut emissions until 2030 would force far greater use of such technologies, a 33-page summary for policymakers said.

If countries delay, the world will have to deploy little-tested options, said Edenhofer, a German scientist from the Potsdam Institute for Climate Impact Research. One method mentioned by the IPCC is to burn wood, crops or other biomass to generate electricity and capture the greenhouse gases from the exhaust fumes and bury them underground.