Bathtub Analogy: Why the Global Temperature Giggles

JohnMashey posted this at Skeptical Science.

A bathtub is being filled [sun], slightly faster than it is being drained [heat radiation]. You have a few floats, measuring the depth of the water. The depth would go up smoothly, except there’s a kid splashing around in the bath.

Sometimes the kid lies back in the water, in which case the overall water level goes up [El Nino], but with waves, so that some floats go down.
Sometimes the kid sits up, in which case the overall water level temporarily goes down [La Nina], but with waves, so a few of the floats go up.

The kid splashes around the whole time, jiggling all floats second by second.

At any point in time, there is a certain amount of water, but the average as measured by 1% of the floats is subject to lots of jiggles.

Still, the water *is* going up, as long as more as coming in than draining out, and the physics of GHGs say that we’re slowly plugging the drain.