NOAA Study: Climate change makes heat waves more likely

20 times Texas heat wave last year 20x more likely according to NOAA/UK Met Office study

The conventional wisdom has been that you can’t pin one extreme weather event on climate change or “global warming.”

That may still be true, but we may have moved into a new era where climate change can be cited as having greatly increased the odds of extreme heat waves.

A NOAA/UK Met Office study released this week brings climate perspective to 6 extreme weather events from 2011.

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The analogy of climate change to individual extreme weather events has been used many times to a baseball player who uses steroids to boost home run numbers. You can’t say any one home run swing was caused by steroids, but can you say it increased the odds…or “loaded the dice” in favor of a home run?

Here’s an excerpt form the study.

One analogy of the effects of climate change on extreme weather is with a baseball player (or to choose another sport, a cricketer) who starts taking steroids and afterwards hits on average 20% more home runs (or sixes) in a season than he did before (Meehl 2012). For any one of his home runs (sixes) during the years the player was taking steroids, you would not know for sure whether it was caused by steroids or not.

But you might be able to attribute his increased number to the steroids. And given that steroids have resulted in a 20% increased chance that any particular swing of the player’s bat results in a home run (or a six), you would be able to make an attribution statement that, all other things being equal, steroid use had increased the probability of that particular occurrence by 20%.

As for the 2011 Texas heat wave, the study concludes the following.

We found that extreme heat events were roughly 20 times more likely in 2008 than in other La Niña years in the 1960s and indications of an increase in frequency of low seasonal precipitation totals. With 2008 serving as our proxy for 2011, this suggests that conditions leading to droughts such as the one that occurred in Texas in 2011 are, at least in the case of temperature, distinctly more probable than they were 40-50 years ago.

The study is detailed and may be one of the first to link specific extreme weather events to climate change.

Stay tuned….

PH