Texas's pasture-desiccating, road-warping devil heat last summer has earned a spot alongside hot spells in Moscow (2010) and France (2003) as one of the wild outliers of a climate pushed to extremes.
A study from the NASA Goddard Institute for Space Studies and the Columbia Earth Institute say global warming has loaded the climate dice. Smart money is on temperature anomalies. Compared with the years for which we have the most information (1951-1980), the data are striking.
The heat we saw last summer has almost no antecedent, the study says. Forty or 50 years ago, you might have seen anomalies like that over a few 10ths of 1 percent of Earth. In the last few years, 10 percent of land areas experienced summer anomalies. "The increased frequency of these extreme anomalies, by more than an order of magnitude, implies that we can say with a high degree of confidence that events such as the extreme summer heat in the Moscow region in 2010 and Texas in 2011 were a consequence of global warming," writes Dr. James Hansen of NASA.
A business-as-usual approach to fossil fuels over the next 50 years, Hansen warns, will guarantee that our record-busting summer becomes commonplace. But it's in the interplay between weather and climate that we must be careful in how we interpret the driest, hottest year we've ever seen, state climatologist John Nielsen-Gammon tells Unfair Park.
"I don't think [the study's data] should be applied to events," Nielsen-Gammon says. "But I think it's fair to interpret it as the overall chances of extreme weather increasing over time."
Without getting too far into the climatological weeds, last summer was five standard deviations above normal. But climate change can only account for some of that increase. Either way, last summer was going to be bad. Nielsen-Gammon says climate change threw an extra log on the fire and turned the state into hell on Earth.
La Niña would have knee-capped the cattle industry with drought, but it was the extreme heat that burned pastures. Weather and climate, in that regard, are difficult to separate. "Places experiencing an extended period of high atmospheric pressure develop dry conditions, which we would expect to be amplified by global warming and by ubiquitous surface heating due to elevated greenhouse gas amounts," Hansen writes.
It works the other way too. The amount of moisture the atmosphere can hold increases alongside temperature. I saw this firsthand during what some believe was a 1,000-year flood in Nashville, Tennessee, in 2010. Rainfall doubled previous records. At one point an entire house was seen floating past a tractor-trailer.
Perhaps the most interesting takeaway from the study is this: Weather variability has always made climate change a difficult thing for the layperson to detect. Problem is, we've never really understood what to look for. But if you're a Texan who was alive from the '50s to the '80s and beyond, whether you know it or not, you watched the Holocene epoch end.
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