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This Material Can Remove Carbon Pollution From the Atmosphere

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By far, the most abundant greenhouse gas is carbon dioxide. It’s emitted when planes fly, cars drive, and power plants burn fossil fuels like coal and natural gas. Much of the global conversation about stemming global warming focuses on cutting carbon dioxide emissions.

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Researchers at George Washington University, however, report that they’ve made significant advances with a new technology that removes carbon dioxide (CO2) from the atmosphere — and produces something valuable at the same time.

The process involves heating up a liquid called lithium carbonate to a very high temperature and passing a small electrical current through it. The final result is a material called carbon nanofibers, and in the process of their formation, carbon dioxide is taken out of the air.

Carbon nanofibers are very strong and used in carbon composites like in commercial airliners. It’s expensive to make, said Stuart Licht, the lead scientist on the project and a chemistry professor at George Washington University. But his method, he said, is a cheap way to make the material. When doing experiments in their lab, they were able to create about 10 grams of carbon nanofibers per hour, a material that is worth $25,000 a ton, said Licht.

They also ran the experiments outside, using the heat from the sun, which produces lesser amounts of the carbon nanofibers.

“We’re very excited that this can provide an economic motivation, an economic impetus, to remove CO2 from the atmosphere, because it is such a useful material,” Licht told VICE News. “Rather than seeing CO2 then just as liability, it becomes a resource to generate the carbon nanofibers.”

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Licht would like to see the process scaled up to help fight climate change, and thinks that it’s “a viable path” to doing so, especially because the byproduct of the carbon dioxide absorption is a useful product. He also notes that the research is in its early stages.

Klaus Lackner, who directs the Center for Negative Carbon Emissions at Arizona State University, said that the research sounded positive because it was a new way of producing an expensive material, especially since it uses air itself as a fuel. But he remained skeptical about whether it could be scaled up to absorb enough carbon from the atmosphere to make a difference against climate change, given the large amounts of carbon dioxide that humanity produces.

The United States, for example, produces 16 tons of carbon dioxide per person per year, a number that has actually decreased, Lackner said.

There are existing technologies for removing carbon dioxide from the air, he said — for example, the way the air in a submarine or space station is scrubbed of the gas. But the challenge is to make that technology cheap enough to scale it up to fight climate change.

At the Center for Negative Carbon Emissions, he said they are researching a way to absorb carbon dioxide from the air passively, and then store it— akin to the way a windmill is a passive device that uses blowing air to create electricity.

“If you want to stabilize climate, you cannot let CO2 [levels] in the air keep rising. Eventually we will have to stop,” Lackner told VICE News. Right now, the concentration of carbon dioxide in the atmosphere is above 400 parts per million (ppm). That number is increasing by more than two ppm per year, he said.

“We will have to stop somewhere, because beyond [a certain point] it hurts too much,” he said.

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But the number will continue to rise as long as there are some emissions, Lackner said. Solutions to this problem involve either capturing as much as carbon dioxide as possible before it is emitted, or stopping fossil fuel use entirely, which can’t be done overnight.

“I’m now reasonably convinced that in all likelihood, we will, within the next 50 years, have to take substantial amounts of CO2 back out of the air,” Lackner added. “That means we need to know how to get [it] out, and we need to know how to store [it].”

Peter Frumhoff, the director of science and policy for the Union of Concerned Scientists, echoed Lackner’s concerns about the efficacy of scaling up the carbon nanofiber technology. He said that new research is welcome when it comes to ways of taking carbon dioxide out of the atmosphere, but that caution was warranted when it comes to the idea that it could be scaled up enough to actually impact the concentrations of the gas in the atmosphere.

“It’s certainly no substitute for steeply reducing CO2 emissions, especially by expanding clean energy alternatives to burning fossil fuels,” Frumhoff wrote in an email to VICE News. “And bear in mind that we already know how to remove CO2 from the atmosphere safely and sustainably at scale through restoring forests and grasslands.”

That technology, he pointed out, is called photosynthesis. 

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Follow Rob Verger on Twitter: @robverger