U.N.: Global Warming Requires a More Frequent Rethink of "Normal" Weather

The baseline for "normal" weather used by everyone from farmers to governments to plan ahead needs to be updated more frequently to account for the big shifts caused by global warming, the U.N.'s World Meteorological Organization said on Wednesday.

The WMO's Commission for Climatology believes rising temperatures and more heatwaves and heavy rains mean the existing baseline, based on the climate averages of 1961-90, is out of date as a guide, the WMO said in a statement.

"For water resources, agriculture and energy, the old averages no longer reflect the current realities," Omar Baddour, head of the data management applications at the WMO, told Reuters.

A government trying to decide where to build river flood defenses or a hydroelectric dam based on average rainfall could be misled by the 1961-90 data, for example, while a farmer studying average temperatures might plant crops that wilt in warmer conditions, he said.

Global Warming Requires a More Frequent Rethink of "Normal" Weather:  U.N.