node created 2017/06/02
Sure, it makes no difference to whether you want to put a sweater on, but that's not the point. The troposphere is vast, and 0.2 C represents an immense amount of kinetic energy, which in turn drives dramatic changes in circulation and precipitation patterns. You can get a sense for this by calculating how much energy an average of 0.2 C represents.

Start with this: how much does a cubic meter of air weigh? Have you ever thought about that? A cubic meter of dry air at sea level weighs about 2.7 pounds. How much energy does it take to raise 2.7 pounds of dry air by 0.2 degrees? It turns out you can look that kind of thing up. It takes about 245 joules.

Now take that 245 joules/m^3 and multiply it by the volume of the troposphere. As you recall from calculus, you can approximate this by taking the surface area of a sphere 6,371,000 meters in radius and multiplying by the troposphere's roughly 11 km height. You should end up with a figure on the order of magnitude of 10^18 joules.

Or you can think of that as being roughly the same as 20,000 Hiroshima sized bombs. Granted the density of air 10 km up is somewhat less, but we haven't factored in the gigatons of water vapor in the atmosphere. Or interactions with the oceans; most of the excess energy goes into the oceans, and that in turn affects climate in countless ways. That's how palm trees grow in Southern Britain, even though Cornwall's further north than Maine.

And yet... You just can't feel a 0.2C change. Then again you can't feel the Coriolis force either, but that can bend a subtle pressure gradient hundreds of miles long into a cyclone, a feat no human agency can resist, much less match.

Scale matters. If there's anything scientific and mathematical literacy should teach, it's that. That's why the future of the planet can't be trusted to a semi-literate ignoramus.