Friday, July 01, 2011

The ‘new normal’ starts today | Climatide


There’s been a lot of talk lately about whether the extreme weather of the past year and a half constitutes a “new normal.” Much of the climate versus weather discussion has focused on the idea that weather happens every day but climate is the average of conditions over a long period of time – 30 years, officially.  So one year isn’t enough to declare a new normal; the 30-year average has to change.

Well, today NOAA and the National Climatic Data Center officially usher in the new normal based on the 30-year period from 1981 to 2010. Two images – portraying the upward tick in both January minimum temperatures (above) and July maximum temperatures (below) – were released early and have been making their way around the web this week.




Two things are immediately apparent:
1. It’s warmer. The first decade of the 21st century was the warmest on record, and the new 30-year average reflects this. It’s particularly pronounced in the winter (less) low temperatures. But overall, Bloomberg reports that the new benchmark temperatures for the U.S. are 0.5ºF warmer than their predecessors.
2. Climate change is a global phenomenon, but the impacts are local and vary from place to place.

These two images, alone, make it pretty clear that climate – not just weather – is changing. But they’re only the beginning. New normals for rainfall, snowfall, and heating and cooling days are also expected today. Additional “supplemental” normals will be released in January 2012. So stay tuned.

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