Global changes in diet, shifting towards vegetarianism from meat, would also help.

Washington - 2011 was a year of “extremes” in global climate patterns, with flooding in Thailand, extreme drought in Africa and a heatwave across Europe, scientists said on Tuesday.

“People may remember this year as extreme weather and climate,” said Jessica Blunden, a climatologist at the US National Ocean and Atmospheric Administration (NOAA).

Global temperatures were actually cooler on average last year than in 2010, due in large part to the La Nina phenomenon that periodically brings cooler waters to the Pacific, according to a study released Tuesday about the state of the climate.

Still, it was warmer than would be expected given the generally cooler temperatures during La Nina and ranks among the 15 warmest years since record-keeping began more than a century earlier.

“Clearly long-term trends continue to show what we'd expect in a warmer world,” said Tom Karl, director of NOAA's National Climatic Data Centre.

The Arctic region continues to warm more quickly than the rest of the world, with sea ice shrinking to the second smallest area on record. Trends show the oceans worldwide retaining more heat. - Sapa-dpa