Help fight global warming, stop shoveling snow

It snowed last night. There was a lovely, six-inch blanket of white on the ground this morning. By 08:00, I had succumbed to spousal, and cultural, pressure, and was out working a shovel, trying to clear the lovely white stuff off the drive and sidewalks. Just like it was something undesirable that had to be got rid of.

I have one strong personal reason not to like cleanly shoveled sidewalks. I walk a lot, usually including an hour after dark in the wintertime, and I know that the really dangerous, slippery sections of sidewalk are those that have been shoveled clean. They may even be mostly dry, but just often enough, there are places where snow on the sides was melting during the day, and water was running across the sidewalk, and after dark this water turned into a sheet of black ice. Those are the slippery places that will surprise you, and put you down on your back.

This morning, however, I was thinking about the way the concrete warms up, once it has been shoveled and the sun gets to it. When the snow covers the ground, nearly all of the light from the sun that hits it is reflected. All that energy (about one kilowatt for every square meter of earth surface) gets turned around without warming anything up, and is headed back towards space, where it came from. The surface of the earth is cold beneath the snow, and it can't get warm because most of the energy that would warm it is being lost into space. That blanket of snow is causing a local episode of global cooling.

However, we have this strong cultural mandate to shovel that snow off the walk. If we don't, our walks sit out there for all the world to see, evidence of our shameful laziness. In many cities there are even laws that require people to shovel their walks. These laws have outlived their usefulness. They should be repealed, and people should be encouraged to leave that snow on their walks. As long as that snow is there, it's better than unplugging a standard electric space heater for every two square meters of concrete you have outside.