The bitter winter afflicting much of the Northern Hemisphere is only the start of a global trend towards cooler weather that is likely to last for 20 or 30 years, say some of the world's most eminent climate scientists.
Their predictions based on an analysis of natural cycles in water temperatures in the Pacific and Atlantic oceans challenge some of the global warming orthodoxy's most deeply cherished beliefs, such as the claim that the North Pole will be free of ice in summer by 2013.
