Putting a number on the earth

We (finally) hear and talk a lot about global warming and carbon footprints. But it all seems very vague and nebulous. I know my impact on the earth is larger than I’d like it to be. I know, as a society, we’re living way out of balance. But what exactly do we need to do to get back into balance?

350.org puts it into perspective:

The most recent science tells us that unless we can reduce the amount of carbon dioxide in the atmosphere to 350 parts per million, we will cause huge and irreversible damage to the earth.

There are three numbers you need to really understand global warming, none of them very complicated. For all of human history until about 200 years ago, our atmosphere contained 275 parts per million of carbon dioxide (that’s the first number).

Beginning in the 18th century, we started to burn coal and gas and oil to produce energy and goods. … By now—and this is the second number—the planet has 387 parts per million CO2 – and this number is rising by about 2 parts per million every year.

In the past year, some of the world’s leading climate scientists have told us what the highest safe level of CO2 is: 350 parts per million. That’s the last number you need to know, and the most important. It’s the safety zone for planet earth.

Wow. Seems like we have some work to do.