A new report by NASA links extreme summer heating events to global warming. The report, which drew temperature data from 1951 to the present showed that extreme events like this year’s US drought, the extreme drought in Russia in 2010 and last year’s Texas drought are now 30 times more likely to occur than they were in 1951-1980. The above curve, produced by NASA, shows a comparison of summer temperature distributions between 2001-2011 and 1951-1980.
Though the report takes into account 2011 data, researchers were quick to point out that the current summer drought and impacts to US agriculture were also linked to human caused global warming. “This summer people are seeing extreme heat and agricultural impacts,” James Hansen, Head of NASA’s GISS, noted. “We’re asserting that this is causally connected to global warming, and in this paper we present the scientific evidence for that.”
The report defined an extreme heating event as the highest summer temperatures experienced by 1% of Northern Hemisphere land masses in the period of 1951-1980. What the research found was that from 2006-2011, fully 10% of Northern Hemisphere land masses experienced extreme summer temperatures. The report also noted that more extreme events were occurring with much greater frequency. Events that previously happened once every 300 years were happening once every ten years.
Hansen says this summer is shaping up to fall into the new extreme category. “Such anomalies were infrequent in the climate prior to the warming of the past 30 years, so statistics let us say with a high degree of confidence that we would not have had such an extreme anomaly this summer in the absence of global warming,” he says.