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Tuesday, January 25, 2011

What's "Normal" Weather Is About to Officially Change

What's "Normal" Weather Is About to Officially Change

by Ben Jervey, contributing editor, environment, GOOD, January 18, 2011
While you've been freezing your tail off for the past few weeks, the National Climatic Data Center has been gearing up to announce new definitions of "normal" weather conditions for 10,000 regions across the country. And these new "normals" are going to be a lot warmer than the current definitions. 
Here's why: The NCDC uses temperature and precipitation data from the previous three decades to calculate what's "normal" for a region. Currently, that includes the relatively cold 1970s. New figures will replace the chilly 1970s with the 2000s, which was the warmest decade ever recorded. Check out the difference in these maps, showing the "temperature anomaly" (defined by NOAA here) for each decade.
2000 to 2009:
GISS, NASA, maps, climate change, global warming

1970 to 1979:
GISS, NASA, maps, climate change, global warming
(For a fuller effect of the longer term climatic shift, click through to NASA's site, where you can watch the past 13 decades flash by.)

So the new "normals" will be considerably warmer and wetter than the current set (which you can examine here on the NCDC site). As ClimateWire's Joey Peters explains, this is by no means an academic experiment:

With these changes comes a pronounced effect on the industries and organizations that rely on the normals...[F]or some businessmen, utility regulators, wildlife agencies and others, tinkering with the meaning of "normal" can mean big changes. They range from future sales and budgetary issues to difficulties with songbirds and trout.
So these numbers really do matter, in the very real world. While plenty of agents of disinformation continue to crow about the very recent cold and snow, the biggest businesses, utilities, and agencies have long since recognized and digested the fact that states and smaller regions are warming as well, and their important work depends on how much. They're anxiously awaiting the NDCD's new "normal" weather numbers, and aren't distracted by a short term blast of Arctic air.
NCDC will release the first batch of new "normals" in June, and the rest by the end of the year.

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