Pulling CO2 from air feasible, if still costly, way to curb global warming

record, based on land and ocean surface temperature measurements, according to the National Oceanic and Atmospheric Administration and the National Climatic Data Center.

The release notes that CO2 can linger in the atmosphere for hundreds of years; to stabilize and possibly reduce it will take concerted, long-term efforts across the globe — including the replacement of fossil fuels as an energy source. The authors contend, however, that is not likely to happen fast enough.

“Stabilizing atmospheric CO2 will require drastic emissions reductions,” the authors write. “Carbon-free renewable and nuclear energy resources are theoretically sufficient for humankind’s energy needs, especially if combined with significant increases in energy efficiency. It is unclear, however, whether these resources can be deployed rapidly and widely enough and overcome socio-political obstacles related to cost, environmental impacts, and public acceptance.”

This is where carbon capture and storage comes in. These emerging technologies have the potential to nearly eliminate CO2 emissions from fossil fuel plants. The authors say, however, that even modest residual emissions of 10 percent from those plants would prevent us from stabilizing atmospheric CO2 in this century. Air capture technology could be used to mitigate that, and also to deal with the potential problem of CO2 leaking from storage systems, some of which include pumping CO2 deep into the ground.

The authors said that those systems do not address all the CO2 coming from more diffused sources, such as in the transportation sector. Those sources account for between a third and a half of society’s total CO2 emissions.

Developing systems to capture CO2 directly from the air could help. The paper looks at various methods. As CO2 passes through the systems, it is pulled into absorbent liquids or surfaces, then separated out. CO2, however, is less concentrated in ambient air than it is coming out of a stationary source like a power plant. The key is to find a way to grab a lot of CO2 out of the air with a minimum expense of energy. Estimating the cost of that technology right now is impossible, the authors said.

If a mass-produced device could capture a ton of CO2 per day, however, a million of them, like forests of artificial trees, could capture more than a tenth of humans’ total output of CO2 today.

The authors caution that the development of various types of carbon capture and storage should not be seen as an argument for doing nothing about how