* Average world temperature may rise 3-6 degrees C
* Cost of CO2 curbs greater if delayed
PARIS, Nov 24 (Reuters) - Global average temperatures could rise by 3-6 degrees Celsius by the end of the century if governments fail to contain greenhouse gas emissions, bringing unprecedented destruction as glaciers melt and sea levels rise, the OECD said on Thursday.
In a report ahead of U.N. climate talks next week in Durban, South Africa, the Organisation for Economic Cooperation and Development (OECD) said the future was grim if efforts to limit the temperature rise to 2 degrees Celsius lacked ambition.
Developed countries used to be the main cause of the rise in greenhouse gas output, but the responsibility would increasingly be shared in decades ahead by the newly emerging economic powers, the Paris-based agency said.
An 80 percent rise in global energy demand was set to raise emissions of carbon dioxide by 70 percent by 2050, and transport emissions were expected to double due to a surge in demand for cars in developing countries and expansion in aviation.
“Governments have to break out of their national mind-sets and look at the global picture,” OECD Secretary General Angel Gurria said in a statement.
“They must speed up negotiations in Durban if we are to meet the internationally agreed goal to limit the global temperature rise to 2 degrees C.”
The warning from the OECD, whose main paymasters are the United States and other developed economies, underscored fears that the commitment to curb climate-heating gases could falter at a time when much of the world is deep in debt.
Of the possibility of a 3-6 degree C rise by the end of the century, the OECD said: “Such a high temperature increase would continue to alter precipitation patterns, melt glaciers, cause sea-level rises and intensify extreme weather events to unprecedented levels.
“It might also exceed some critical ‘tipping-points’, causing dramatic natural changes that could have catastrophic or irreversible outcomes for natural systems and society,” it said.
The report adds to growing calls for action before delegates from nearly 200 countries meet in Durban from Nov. 28 for climate talks, with the most likely outcome expected to be modest steps towards a broader deal to cut greenhouse gas emissions.
U.N. climate scientists, the International Energy Agency and others say global pledges so far to curb emissions of CO2 and other greenhouse gases are not enough to prevent the planet heating up beyond 2 degrees Celsius, a threshold scientists say risks an unstable climate in which weather extremes become more common and food production more difficult.
The U.N. Intergovernmental Panel on Climate Change (IPCC), in a report last week, warned of an increase in heatwaves and the likelihood that much of the world will be subjected to heavier rainfall, more floods, stronger cyclones, landslides and more intense droughts as the Earth’s climate warms.
Backing use of carbon taxes and schemes that contain carbon via tradeable emission permits, the OECD cautioned against reneging in tough economic times on measures to curb greenhouse gases or settling for insufficient commitments made at previous international talks in Copenhagen and Cancun.
Failure to introduce carbon-capture technology widely would raise the cost by about one third of meeting the commitment to limit the temperature rise to 2 degrees C, said the OECD.
In the wake of this year’s Fukushima nuclear disaster in Japan, the OECD also served a reminder about the cost of pulling out of nuclear power, an alternative to carbon-based energy.
The cost of keeping the temperature rise to 2 degrees would rise by some 50 percent if nuclear power was phased out, it said. (Reporting By Brian Love; Editing by Janet Lawrence)