Climate change makes criteria used to predict weather obsolete, UN says

The criteria used by everyone from farmers to governments to predict normal weather patterns need to be updated more frequently to account for significant changes caused by climate change, the U.N.’s World Meteorological Organization said Wednesday.

The WMO's Commission for Climatology believes that rising temperatures and more frequent heat waves and heavy rains mean that existing criteria, based on climate averages from 1961 to 1990, are out of date.

The commission’s report highlighted growing concern among governments and businesses that climate change will disrupt not only the environment but also entire economies and nations. It comes just two months after a report from the Obama administration warned of dire consequences for every business sector and every region of the U.S. if climate change is not slowed.

"For water resources, agriculture and energy, the old averages no longer reflect the current realities," Omar Baddour, head of 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.

Under current rules, the 1961–90 baseline is due to be updated in 2021 with the data from 1991 to 2020. The Commission for Climatology wants to see rolling updates every decade, making the current baseline 1981–2010 and the next period 1991–2020.

Some weather services have already adopted new baselines, which just causes confusion, the WMO said.

"Different researchers and weather services are using different baselines, which results in inconsistent comparisons," it said.

Baddour said the WMO also wants to retain the 1961–90 benchmark to judge long-term trends in climate change.

Last year, the U.N.'s panel of climate scientists raised the probability that human activities, led by the use of fossil fuels, are the main cause of global warming to at least 95 percent from 90 in a previous assessment in 2007, and this year said the effects of climate change are "worse than we predicted."

Al Jazeera and wire services