US Record High Temperatures Double Record Lows Over Past Decade

thermometer photo

photo: Mr. T in DC via flickr.

Striking one against the 'it's so cold outside that global warming must be a myth' crowd comes this next piece, via Science Codex. Research to be published in the journal Geophysical Research Letters shows that over the past decade the number of record hot days has been double the number of record cold days:The research was carried out by scientists at the National Center for Atmospheric Research, Climate Central, The Weather Channel, and the National Oceanic and Atmospheric Administration, and examined temperature records going back to the 1950s.

Expected Ratio Over Time Is About 1:1
They found that from Jan. 1, 2000 through Sept. 30, 2009 in the continental US, there were 291,237 record high temperatures set versus 142,420 record lows. In 2009, even though weather in the US was slightly cooler compared to the previous two years, the ratio of record highs to records lows was still "more than three to two".

Going farther back, in the 1950s that ratio "slightly exceeded one to one", in the 60s and 70s it evened out a bit, before starting a warming trend in the 1980s.

Nights Aren't Cooling As Much As They Used To
Interestingly, the study also found that part of the reason for the 2:1 ratio can be attributed to comparatively smaller numbers of record lows than huge numbers of record highs -- indicating that much of current warming is occurring at night, something which is "consistent with years of climate model research."

So how bad is going to get and are we still going to have winters?
In short, if we don't get off a business as usual trajectory, pretty bad, but we still have winters and still set new record lows.

Report lead author Gerald Meehl:

One of the messages of this study is, you still get cold days. Winter still comes. Even in a much warmer climate, we're still setting record low minimum temperatures on a few days of the year. But the odds of shifting so there's a better chance of daily record highs instead of lows.

Looking forward, the researchers say that business as usual emissions trajectories will increase the record high to record low ratio to 20:1 by 2050 and 50:1 by 2100. However, by mid century if emissions are constrained that ratio will only increase to about 8:1.

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