Climate Science for Everyone: heavy snows are expected in a warming world

Posted on April 1, 2012

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There are people who say that heavy snowfall means that human-caused climate disruption must be wrong. This is a misunderstanding on their part. Fortunately, it’s quite simple to correct the misunderstanding.

You can live nearly anywhere and have personal experience of how hotter air has more water vapor in it. It always feels much more humid when it’s hot than when it’s cool. My personal experience with this was visiting Connecticut in late August, when it was 95 degrees out with unbearable humidity.

It’s also the case in the winter. There’s a reason why the Front Range of Colorado (where I live) gets more snow from an upslope flow than from any other weather condition – the warm air from the Gulf of Mexico has a lot of water vapor in it, and when that air cools down as it’s forced to higher (and colder) elevations by the Rocky Mountains, the excess water vapor freezes and falls as snow.

When you look at the image above, you’ll notice that the bottom temperature scale is in Celsius, and that the maximum value is 0 °C, or freezing (32 7deg;F). At that temperature, air has about 3.8 grams of water vapor per kilogram. But at -10 °C (14 °F), there’s only about 1.6 G of water vapor per kilogram.

Let’s use a very simple example to illustrate this better. Say that a snowstorm at 14 °F produces a 8 inches of snow before it runs out of water vapor. That identical snowstorm at 32 °F would produce 19 inches of snow before it ran out of water vapor.

Put into in the context of human-caused climate disruption, this means that a warmer world will have more water vapor around. In the winter, when the air temperature is at or below freezing, that additional water vapor will fall as heavier snows.

So the next time someone tells you that more major snowstorms disprove climate disruption, you’ll know that they just don’t know any better. In reality, more major snowstorms are an expected result of climate disruption.

Image Credit: Science of Doom

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