[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/02/EW-03-01-12-Weird-Weather.mp3|titles=EW 03-01-12 Weird Weather]
This past year held some weather extremes—drought in Texas, floods in the Midwest, and an early snowstorm in New England. Neighbors who do not believe in climate change love to point and laugh at me whenever there is a deep snow in our small northeastern town.
Yet, scientists predicted that weather extremes would be one of the early outcomes of human-induced global warming. If you raise the average temperature, a handful of hot days every year will be much hotter. Analyses of temperature records show a distinct trend towards warming during the past decade. And yes, the weather has gotten weirder.
When it’s warm, the atmosphere holds more water vapor, which drives rainfall. Since hurricanes and other cyclonic storms gather moisture from a large area, we can expect an uptick in severe rain events in a warming world. When these storms occur in the winter, they will deliver large amounts of snow, relative to historical records.
“A warmer atmosphere can hold more moisture,” says Kevin Trenberth of the National Center for Atmospheric Research. “This means the relative humidity remains about the same, but the actual amount of moisture in the atmosphere goes up – about 4% for one degree Fahrenheit – and as long as the temperatures are cold enough over the land, that extra moisture can fall in the form of snow. And so it’s quite possible to get bigger snowfalls.”
We need to brace ourselves for an increase in the number of very hot days, big rainstorms, and big snowfalls. These changes in our climate may demand changes in our infrastructure—cooling systems for large buildings, culverts for storm-water drainage, and equipment for snow removal.
All part of the list of expenses that global climate change will demand of us.
Web Extra
Kevin Trenberth of the National Center for Atmospheric Research discusses the recent changes in precipitation in the United States…
[audio:http://wamcradio.org/EarthWise/wp-content/uploads/2012/02/WeirdWeather-Trenberth-webexra.mp3|titles=WeirdWeather-Trenberth-webexra]Photo, taken on August 4, 2009 using a Nikon D90, courtesy of Zanthia via Flickr.