Like clockwork. Snow arrives and climate deniers lose their freaking minds.
There are insights to had in the Rutgers University Snow Lab data.
What might at first glance be puzzling, for instance, while overall annual snow cover is decreasing, Fall Snow extent in the Northern Hemisphere is increasing in recent decades.
This does make sense if we understand that with more moisture in the air, those first few puffs of sub-freezing air are going to cause some precipitation.
Likewise, Northern Hem Winter extent is showing a small rise. In some places, like northern Russia and Siberia, the increase in open water in the Arctic Ocean can create even deeper snowfall due to increased evaporation.
The greatest impact of a warming planet is most clearly visible in spring snowfall.
Below, around 2012, I discussed this with Jennifer Francis, who at the time was still at Rutgers, and very familiar with the data. (She is now at Woodwell Climate Research Center).
Here we can see why, in places like North America, snow that is receding and evaporating earlier in the season means that farm fields and forests get uncovered, and begin, in an increasingly thirsty atmosphere, to dry out sooner.
When the hotter-than-historically average summers arrive, those fields and forests are more vulnerable to drought, drying, and in the case of forests, fire.
For climate deniers, it’s just one more opportunity to deceive themselves and any unwary readers.
Someone wanting to deny the reality of climate change absolutely doesn’t want their believers to think much about the fact that an increase in open water surface on the Arctic now doesn’t mean the air flowing over the surface in winter/spring isn’t below freezing – so will evaporate and then freeze out water from the ocean surface.
I’m in Chicago and we’re going have the kind of conditions tomorrow that make for heavy snowfall – not super cold weather which reduces snow, but weather just around the freezing point, where moisture isn’t yet squeezed out of the air mass. The deniers are instead coached and nudged to think that any shift of temperature UP must mean it can’t snow. People who simply look at how weather works know otherwise.
The driest times in the last few millions of years have been when ice cover reached farthest over the continents. Warmer means more water vapor and yet “warmer” isn’t automatically “above freezing”.