Renewables, nuclear should triple to save climate, UN panel says

The world needs to triple the energy it gets from renewables, nuclear reactors and power plants that use emissions-capture technology to avoid dangerous levels of global warming, United Nations scientists said.

Investments needed to keep climate change within safe limits would shave a fraction of a percent off annual global growth, the UN said on Sunday in the third part of its most comprehensive study on warming.

A delay in stemming rising greenhouse gases will cut chances to limit the global temperature increase, add to costs and lead to increasingly reliance on unproven technologies, they said.

“The longer we wait to implement climate policy, the more risky the options we’ll have to take,” Ottmar Edenhofer, a co-chairman of the 235 scientists who drafted the report, said in a phone interview from Berlin. “We need to depart from business as usual, and this departure is a huge technological and institutional challenge.”

The UN said governments must accelerate efforts to build wind farms and solar parks and provide incentives to develop carbon capture and storage (CCS) technology for fossil-fuel plants by making it more costly to emit carbon. The study aims to guide envoys from 194 nations next year as they devise a new accord to slash greenhouse gases.

The researchers said emissions growth accelerated to an average of 2.2 percent a year for the 2000-2010 period from an annual 1.3 percent the preceding three decades. That puts in jeopardy the target agreed upon by climate-treaty negotiators to stabilize warming since pre-industrial times to below 2 degrees Celsius (3.6 degrees Fahrenheit).

The possible situation in 2100 is “either you’ll have some fossil-fuel power generation with carbon capture and storage, or a complete switchover to renewables and smart energy storage,” Jonathan Grant, director of climate change at consultants PwC in London, said by phone. “The problem with some of those scenarios is the transition takes too long.”

Global greenhouse-gas emissions would have to be lowered between 40 percent and 70 percent by mid-century from 2010 levels, and to “near-zero” by the end of the century, efforts that would be likely to limit warming to 2 degrees Celsius, the UN Intergovernmental Panel on Climate Change said on Tuesday in a statement handed out in Berlin.

Without extra effort to cut greenhouse gases, current trends may triple their concentration in the atmosphere this century, pushing warming since 1750 from 3.7 degrees Celsius to 4.8 degrees Celsius, according to the report. That would raise the risk of melting glaciers and sea ice, lengthening droughts and heat waves and intensifying storms and flooding. –Bloomberg News