Global cooling theories put scientists on guard

By Gerard Wynn

LONDON (Reuters) - A new study suggesting a possible lull in manmade global warming has raised fears of a reduced urgency to battle climate change.

The U.N. Intergovernmental Panel on Climate Change (IPCC), a group of hundreds of scientists, last year said global warming was "unequivocal" and that manmade greenhouse gas emissions were "very likely" part of the problem.

And while the study published in the journal Nature last week did not dispute manmade global warming, it did predict a cooling from recent average temperatures through 2015, as a result of a natural and temporary shift in ocean currents.

The IPCC predicted global temperature increases this century of 1.8 to 4 degrees Celsius.

So the Nature paper has sparked worries that briefly cooler temperatures may take the heat out of action to fight the threat of more droughts and floods, while a debate about the article's findings has also underlined uncertainty about such forecasting.

Most scientists oppose the minority that has used the present lull in warming to cast doubt on the size of threat from manmade global temperature rises.

"Let's say there wasn't much of a warming for the next 10 years, how will the public and politicians play this out?" said Bob Watson, former IPCC head and current chief scientific adviser to Britain's environment ministry.

He said it was important to explain that fluctuations were an expected part of a general, manmade warming trend.