Sunday, May 3, 2015

Global Warming and Moderate Weather Events

The evidence continues to accumulate that global warming will lead to climate change; specifically, that extreme weather events will become more common. And now there's yet more evidence. The authors of a recent paper looked at past incidences of more moderate events, such as daily heat waves and precipitation events large enough to occur once every three years. Then, using a climate model, they predicted the number of such events in the future depending on the extent of global warming.

According to their model, so far global warming hasn't had much of an effect on moderate precipitation events. However, if global warming increases to 2o C we can expect the number of moderately heavy precipitation events to increase by about 65%.

The effect of global warming on moderate heat waves, however, is much worse. Already, the 0.85o C rise in global temperatures since pre-industrial times has increased the number of moderately hot days by about 5-fold. If global warming rises to 2o C we can expect another 5-fold increase in hot days.

Of course, predictions about the future are based on climate models; models that are developed based on past experience. Predictions may or may not come to pass. But climate models are getting better every year; we ignore them at our peril.

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