Tons of CO₂ pollution. We are always hearing about how many tons of CO₂ pollution we emit. The average American car emits about seven tons of CO₂ in a year; the average American family, about 24 tons; the United States as a whole, over seven billion tons; and worldwide, almost 30 billion tons. The Virgin Earth Challenge (see last week’s post) offers $25 million to whoever can economically remove one billion tons of CO₂ from the atmosphere each year.

But what is a ton of CO₂?

People keep saying to me, I thought CO₂ is a gas. How can a gas have weight? I explain that CO₂ is made up of atoms, and atoms have mass, and with gravity mass has weight. As often as not, my explanation is met with a blank stare. So let me try a different tack.

Picture a football field, and then imagine a round balloon with one end lined up on the goal line and the other on the 10 yards line – that is, a balloon with a diameter of 10 yards. If that balloon were filled with CO₂, it would weigh about 1 ton; it would be a 1-ton CO₂ balloon.

In 2006 an American family emitted the equivalent of 24 CO₂ balloons by powering their home, driving their cars and flying. If you lined those balloons from end-to-end they would go from goal line to goal line almost two-and-a-half times – 240 yards!

Within a year or two, a little more than half of those CO₂ balloons will be absorbed from the atmosphere into the ocean or trees. Unfortunately, the rest of the balloons will hang around for a very long time. One hundred years from now there will still be almost half a football field of CO₂ balloons left to overheat the earth. And that’s just the CO₂ from one family in 2006. There will also be CO₂ balloons from 2007, 2008, and so on.

In total, Americans were responsible for more than seven billion CO₂ balloons in 2006. Lined up end to end they would circle the earth 1,600 times, and the number grows each year. Isn’t it about time we start taking the CO₂ out of some of those balloons?

Do you have ways of your own to imagine what a ton of CO₂ looks like? If so, post them here! If I think of other ways to visualize a ton of CO₂, I’ll add them, too.