What We Can Do About Global Warming The world, long content with living off carbon, is now restless with new ideas. And a range of solutions are on the table, from carbon "vacuums" to energy sources relying on wind, water and trash.

What We Can Do About Global Warming

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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.

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 5:

There's not much we can do about the carbon atom. It is what it is. It makes bonds, breaks bonds and hugs oxygen. And nobody — not you, not me, not Albert Einstein, not a pack of Einsteins — can change that.

Yet we have a carbon problem. There's too much carbon dioxide in the atmosphere. It's trapping sunshine and very possibly warming the planet. So if carbon won't change (and it won't, it hasn't for billions of years), what do we do?

Well, we can hope some very clever person has a very clever idea, like a flying CO2 vacuum cleaner, for example. Imagine a guy flying over Beijing or a burning coal field, collecting all the CO2 from the atmosphere. This notion has a technical name, it's called "carbon sequestration." You can't do this in a flying machine yet. But the idea is to go to places where carbon dioxide has gathered in high concentrations and what you do is remove some of the CO2, as in "suck it up."

Actually, this principle has already been tested in real life in real places. There are non-flying vacuum-like machines inside power company smokestacks. They are called "scrubbers." What they do is capture the CO2 coming up a smokestack before it gets into the air, and the concentrated CO2 is then gathered, transported and eventually shoved down a hole. Usually a deep hole, where it's supposed to sit for a long, long time.

The advantage is extra CO2 doesn't get into the air. The disadvantage: It's expensive to isolate CO2, expensive to transport, expensive to find and fill a hole, and the hole might leak.

The other possibility is to use less carbon. We rely on oil and coal and natural gas (all carbon-based) to heat ourselves, cool ourselves, light our homes, drive our cars, run our businesses. Carbon is, even now, cheap, abundant and releases energy easily. That's why it has been popular since the first cave person burnt a log. But carbon is not the only atom in town. We can shop around.

In France and Japan, they like uranium. Of course, uranium has its problems (that unfortunate accident in Ukraine). President Bush likes hydrogen. He hopes hydrogen one day will power cars. But that day is not around the corner.

The alternative to alternative atoms is to grab energy from nature itself: from the sea sloshing about (hydro), from the wind blowing (windmills), from underground heat (thermal), from raw sunshine (solar), from grass (biofuel), from trash. The world, long content with living off carbon, is now restless with new ideas.

China is looking for carbon alternatives because in so many cities the air is almost toxic. Same with India. Bangladesh is worrying about sea levels. Everyone is worrying about changes they can't control, so the hunt for solutions is on.

And the best way to find a solution is to understand the problem. This series has concentrated on carbon, the main actor in this drama. We know a lot about carbon: its habits, its attachments, its strengths.

Carbon has been bonding with oxygen, forming CO2 molecules and behaving predictably for billions of years. So if we have a "carbon problem," the mechanics are not mysterious. Carbon is merely following nature's laws. If anything is going to change it will have to be us. But considering that we humans (water aside) are two-thirds carbon ourselves, we carbon life forms will have to solve our carbon problem.

In the end, as we said in the beginning, it's all about carbon.

Special thanks to Dan Nocera, professor of chemistry at the Massachussets Institute of Technology and to NPR's Anil Mundra for research and design.