16 February 2012 | Alan Bouquet
Climate Change, North America

 

The drought of the 1930's led to the dust bowl, will this event become commonplace in future due to climate change?

The US has often been regarded as a place of extreme weather. Temperatures range from sub zero winters in the north, to some of the hottest places on Earth in the summer in the south. A study by the Lawrence Livermore National Laboratory has now confirmed that the number of extreme summer temperature events is increasing, and will continue to do so with climate change.

The study looked at observations and climate model results to show an increase in some regions of the US. “The observed increase in the frequency of previously rare summertime-average temperatures is more consistent with the consequences of increasing greenhouse gas concentrations than with the effects of natural climate variability," added Phil Duffy, lead researcher on the study. It also is very unlikely chance could be playing a part in the observations.

The study compared the 1975-2000 period to the preceding 25 years to find that both observations and climate model results show an increase in the number of warm summers. The success of the models in predicting the observations is important, in that it shows yet again that global climate models are becoming better at simulating the changes in extreme temperature occurrence.

Taking this forward, the team looked at summers in the middle of the coming century, finding that the models suggest hot summers that were rare in the 1950-75 period will become commonplace from 2035-64. "What was historically a one in 20-year occurrence will occur with at least a 70 percent chance every year. This work shows an example of how climate change can affect weather extremes, as well as averages."

In a region with drought worries hanging over it, there is now the very real possibility of both extremely warm and dry summers affecting the country.
 

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