Episode 4: When Carbon Falls in Love, the World Heats Up
To get to the heart of the global warming story, the very heart of it, it turns out that the scientific explanation hangs on the behavior of one very particular atom - carbon.
So the more you know about carbon, the more you'll know about global warming. In a five-part cartoon series, NPR's Robert Krulwich explains the chemistry behind this special atom. Here, episode 4:
Carbon, as you know from our previous episodes, is a very social atom.
Not only does it like grabbing onto other atoms, it doesn't like being alone. So when we break a carbon bond (see episode 3), the lonely carbon immediately looks around for a mate, and the mate it prefers above all others, because it is so stable, dependable and efficient, is ... oxygen.
But whenever possible, carbon will bond; that is, grab onto an oxygen atom. (We're imagining oxygen from carbon's point of view and assuming that Carbon is a guy.) And carbon doesn't like just one Oxygen atom. It's a polygamist. Carbon likes two mates. The most stable — and therefore the most desirable — arrangement for a carbon atom is to find a pair of oxygen atoms and fasten onto both of them, creating the molecule we call CO2.
In fact, this arrangement is so stable, carbon with two oxygens — or carbon dioxide, as you've called it most of your life — is very hard to pry apart. Once a CO2 molecule forms, it tends to stay intact. You can find it in rocks, in the oceans; it is escaping into the atmosphere.
CO2 does have an enemy: trees. Trees "eat" CO2.
But unfortunately, we are adding more CO2 to the atmosphere than we are planting trees. The trees can't keep up. And as countries grow richer and build more factories and engines and homes and cars and planes and trucks, we are using more oil, more coal. And as we've learned, burning oil and coal "breaks" carbon bonds. Carbon then grabs onto oxygen, which creates more and more CO2. We now have so much "new" CO2 in the atmosphere, it is trapping sunshine, which is warming our globe, creating the problem we now call global warming.
Special thanks to Dan Nocera, professor of chemistry at the Massachussets Institute of Technology and to NPR's Anil Mundra for research and design.