When I first wrote about Laughlin’s essay What the Earth Knows, I focused entirely on the foolishness of equating the survival of the earth with the survival of human civilization, and that the phrase Save the Planet was never meant to be taken literally. But I missed Laughlin’s contradiction.
- On one hand: Carbon dioxide from the human burning of fossil fuel is building up in the atmosphere at a frightening pace, enough to double the present concentration in a century. This buildup has the potential to raise average temperatures on the earth several degrees centigrade, enough to modify the weather and accelerate melting of the polar ice sheets.
- On the other hand: Climate change, by contrast, is a matter of geologic time, something that the earth routinely does on its own without asking anyone’s permission or explaining itself.
So which is it?
The truth is that climate changes due to what climatologists call forcings. Some of them act on very long time scales (aka geologic time), while some (such as our greenhouse gas emissions) act over much shorter time scales.