From the ABC 7 Weather team

Summer of 2012: Just Hot or Did We Do It?

September 14, 2012 - 10:17 AM
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Is the recent hot summer another indication of global warming?

The recent break in the heat and humidity have sure been welcomed by all of us. This summer (June-August) was another hot, humid DC summer and the 3rd hottest in Washington weather records. In a recent report and data compiled by the National Climatic Data Center, also the 3rd hottest summer in the United States.

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 More evidence of climate change and global warning . . . or just one of those hot summers we get in DC? As I pointed out recently, the urban heat island effect has had a significant impact on the temperature records of Washington, officially recorded at Regan National Airport since the early 1940s. This past summer the temperature at Dulles Airport was almost 4°cooler than at DCA so we have to be careful. Right now here in Washington, we are on a pace to have the warmest year in weather records.  

Both at Washington National and Dulles.  The placement of weather instruments and the changes of of environments around the instruments are important as an AGW critic blogs about. It's important to have critics and critical comments.  But we all, you and myself, the AGW unconvinced, and sure, the climate scientists have to be careful we don't have biased blinder on.  An interesting read on this is Matt Ridley's recent columns in the Wall Street Journal on"confirmation bias".  Here is his third of three columns on this.  All three sure worth a read for all of us.  But, looking at summer and annual temperatures in the DC area and the globe, the trends all point in the same direction. The average temperature is slowly increasing. 

 

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Sure as you can see there are year to year variations and even variations over decades, the slow warming is sure not a smooth upward curve but the trend is clear. The big question is how much of this warming have human footprints. How much is natural and how much is “us”. I don’t think anyone would argue we have NO impact on our environment. Look at this recent TERRA satellite image from 400 miles above us. 

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See any human footprints on the environment?  We sure have changed the land and environment around Washington DC. As a prominent critic of “simple” climate answers, Roger Pielke Sr. argues “The needed focus for the study of climate change and variability is on the regional and local scales. Global and zonally-averaged climate metrics would only be important to the extent that they provide useful information on these space scales.”  But the global "metrics" or footprints are important in that they are showing more and more evidence and confirmation of ideas and projections made years and years ago. Some of the first global projections made decades ago by leading climate scientists such as Warren Washington, forecast more rapid warming and impacts at higher latitudes.  the very latest satellite measurements of sea ice extent in the arctic ocean is now at a record low.  

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Oceans continue to become more acidic as the majority of carbon released in worldwide burning of fossil fuels is absorbed by the oceans but also forms carbonic acid. 

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The evidence continues to mount that we are having an impact on our local, regional, and global environment, weather patterns and climate.  Does that mean next summer even hotter or no snow this winter?  of course not.  there are many strong natural factors, ocean temperature patterns, long term cycles, natural variability still not well understood.  Look at the regional summer temperatures across the United States.  

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 "Third hottest summer in the United States" but not in the Southeast or parts of the Pacific Northwest. So what about next summer?  Look again at the variability of average summer temperatures across the United States.  

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The long term trend is clear, but the year to year variability is also clear.  I deal with probabilities so I'll go out on a limb and say I think it is unlikely next summer in Washington will be our 4th really hot summer in a row.  Then to answer the question in my title.  Did "we" make the past summer as hot as it was?   I think the answer is no . . . but we sure helped make it hotter than average and our footprints of a warmer world, probably a warmer DC area in the coming decades are clearer and clearer all the time.  Some of my colleagues don't agree.  I look forward to their blogs on climate and if there is a human "footprint" on our environment, climate and weather patterns.  Meanwhile enjoy what many folks say is their favorite 3 months of the year.  See our poll and have a great weekend

 

 

 

 

 

 

 

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