How fast does the Earth change temperature?

How fast does the average temperature change on Earth?

Check out this amazing comic strip.

It’s pretty mind-blowing stuff.

Food for thought:

1. How could you mathematically describe the change in the rate of change of temperature (eek – tough wording!)?
2. How do scientists measure average world temperature anyway?

Munroe, Randall. “Earth Temperature Timeline.” Xkcd. http://xkcd.com/1732/.