Gregory Nemet, who studies energy systems and the environment at the University of Wisconsin, said that these technologies hold promise and could be scaled up to remove large volumes of CO2 — but he pointed out that they also “have side effects and concerns.” For instance, a demand for land to grow biomass for energy could end up impacting agriculture for food.
“One of the big concerns we have about climate change is food availability, crop yields, and water use, and here we’re talking about a solution that uses water and takes land that’s used for food,” Nemet told Seeker. “Those are things societies are pretty sensitive to, and small disruptions can have really big influences.”
Both of these carbon-capture technological processes are “in their infancy,” Levin said, and have potential drawbacks that would have to be overcome. The energy needed to suck CO2 out of the sky would need to be carbon-neutral, for instance, to avoid compounding emissions for the sake of absorbing them.
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Meanwhile, at least two companies are already attempting to capture CO2 from the air on an industrial scale. The first, operated by the company Climeworks in Switzerland, went online in 2017 and is aiming to capture 1 percent of global emissions by 2025. The second, based in British Columbia and developed by the company Carbon Engineering, reported in August that it could capture up to a million tons of CO2 at a cost that’s competitive with other renewable energy technologies.