[ASSURAS] When we think of recycling, we tend to think of recycling things, like plastics and glass. But what if the solution to climate change is found not in capturing carbon but in recycling -- that's recycling exhaust fumes from tailpipes? Well, scientists are doing some extraordinary work to make it possible, as Josh Zepps tell us in this energyNEXT.

[ZEPPS] This story is about a technology that will either end up being the most pointless, useless, dead-end idea ever, or just might literally save the world.

[KEN CALDEIRA] We know that the Earth is getting hotter. The ice caps are starting to melt. The weather patterns are changing.

[ZEPPS] Ken Caldeira is an atmospheric scientist with the Carnegie Institution at Stanford University. He's a really nice guy, but, when it comes to cleaning up our atmosphere, frankly, he's kind of a downer to talk to.

[CALDEIRA] This transition to a renewable or carbon neutral energy system could easily take 50 or 100 years, even if we started working on it hard today, which we're not doing.

[ZEPPS] So, what do we do? One idea is to capture all those molecules of carbon from smokestack emissions and try to store them underground. But two scientists in New York are thinking a whole lot bigger than that.

[ALLEN WRIGHT, LENFEST CENTER, COLUMBIA UNIVERSITY] So we can swing the CO2 level up and down, inside this box, using this material.

[ZEPPS] And it works?

[WRIGHT] Like a dream.

[ZEPPS] At the Earth Institute's Lenfest Center for Sustainable Energy at Columbia University, Allen Wright has helped create a type of plastic leaf that soaks up carbon dioxide from the air.

[WRIGHT] If you take CO2 out over here and you add CO2 over here, you still have the same amount of CO2 in the atmosphere, so you can remove CO2 anywhere you want, and it can deal with emissions from anywhere else on the planet. It's a very attractive aspect.

[ZEPPS] So you could coat Nevada in this stuff and it could be soaking up the carbon that's being emitted in Shenzhen.

[WRIGHT] Exactly.

[ZEPPS] Trees are the lungs of the Earth, soaking up CO2 from the air. So the idea here is to mimic Mother Nature by deploying small-scale units of plastic trees that soak up more CO2 than real trees, for longer, wherever you might need them to.

[KLAUS LACKNER, LENFEST CENTER, COLUMBIA UNIVERSITY] In the jet engine of an airplane, there's no practical way to capture it, so that CO2 has no value, it's a waste. And in other places, you do need CO2. You make fizzy drinks, you make dry ice. There are lots of industrial purposes for CO2, and that CO2 needs to be purchased.

[ZEPPS] We use CO2 -- in the petroleum industry by injecting it into wells to enhance oil recovery, in the health care industry to improve blood chemistry in patients, in agriculture to grow algae for conversion into biofuels, in plastics to reduce the amount of oil used -- we even use it to decaffeinate coffee. Think about it. The carbon dioxide in the bubbles that fizz up your nose was paid for by a soft drink company and shipped to their plant, even though there's already too much carbon dioxide just hanging around in the air, and it's free. The trick is to capture it.

[WRIGHT] The whole process is two steps, really. You want to put this outside where it's going to capture CO2 from the air, but then, in order to use this again, you have to get the CO2 off of it. And how we do that is by making it wet.

[ZEPPS] The special plastic was originally used for water purification. Lackner's breakthrough was using it to absorb gas from the air. Once the carbon has been soaked up by the plastic leaf, to release it, you just wet the plastic and catch the bubbles. Lackner says a device about the size of a large tree would collect one ton of carbon a day.

[LACKNER]The tree, over its lifetime, collects a few tens of tons. So we're about a thousand times better than a tree.

[ZEPPS] [Chuckles] Well, look at you, Mr. "a thousand times better than a tree."

Mopping up excess carbon has some big advantages over merely scrubbing it out of power plants. But the challenge is figuring out ways to use the tens of billions of tons of CO2 that we've been emitting for years. Well, Lackner and Wright have a surprising idea.

[WRIGHT] You can add hydrogen to those carbon atoms and re-create gasoline.

[Needle scratches record]

[ZEPPS] Wait -- "re-create gasoline"? Isn't the whole point to get us off gasoline? Well, not according to Lackner.

[LACKNER] Sticking with liquid carbon-based fuels is very interesting because they are so powerful.

[ZEPPS] It's what Lackner calls "closing the carbon loop." You'd collect carbon from the air, use it to make gasoline, burn the gasoline as a convenient source of energy, and then collect the carbon again. On an increasingly crowded planet, soaking up carbon may actually be more efficient than reducing emissions alone.

[WRIGHT] Number one, it has a zero net impact on the environment because you're taking the carbon out that the burning of the gasoline will put in. And number two, you're separating the availability of carbon-based fuels from any geopolitical situation that exists in the world today.

[ZEPPS] The Saudis are going to hate that.

[WRIGHT] It's going to be a game changer, if that's possible to do.

[ZEPPS] But surely there must be major technological challenges to overcome before this idea could really work.

[WRIGHT] There's no real major discovery or invention that has to happen that would prevent us from deploying that technology tomorrow. It's pretty much -- it can go.

[ZEPPS] The challenge, of course, is making the technology profitable on a large scale. The researchers expect to be able to sell carbon dioxide to industry for as little as $30 a ton. That's a competitive price. And what would really make the technology take off, they say, is a tax on carbon dioxide emissions. But that kind of tax would push up the price of carbon-based fuels -- in the case of gasoline, by about 25 cents a gallon. Not exactly an idea that's catching fire in Washington right now.

[CALDEIRA] I think if there was a real crisis and people said, "We really need to do something desperately," then people would be willing to put their resources into it. Of course, it would be much cheaper to do the right thing now, but we don't seem to be doing that.

[ZEPPS] Are you confident that we're going to be able to reduce emissions to such an extent that this work will be redundant?

[WRIGHT] I think... no, probably not. I don't think we will.

[ZEPPS] Someday, tweaking the carbon levels in the atmosphere could be as simple as fiddling with a thermostat is today. Yes, it's far-fetched, but every really big idea was far-fetched once. In Stanford, California, Josh Zepps, "energyNOW!"

[ASSURAS] While the idea may be far-fetched, the basis for it was actually quite simple. Working with his daughter for her eighth-grade science fair, Klaus Lackner, the gentleman of the piece, found that a simple device -- a fish pump -- and sodium hydroxide captured carbon in a test tube. Claire won the science fair, and Klaus turned that small project into today's research that could have a huge global impact.