Capturing and Using Atmospheric CO2

Carbon dioxide_, or CO₂, is one of the three most prominent greenhouse gases, along with methane and water vapor, that trap infrared radiation in the earth’s atmosphere. Concentration of greenhouse gases contribute to the rise in average temperature. Increased temperature is, in turn, responsible for the increase and intensity of destructive weather events.

Reducing atmospheric CO₂ requires limiting use of fossil fuels for transportation and energy generation that release CO₂. It is also possible to remove CO₂ that is already in the atmosphere. Industrial processes and generation of electricity by utilities burning fossil fuels are major sources of CO₂. Carbon capture and storage (CCS) is a technology currently in use to capture CO₂ emissions produced by these sources. The captured gas is transported by pipeline, tanker or ship to users, or is stored well below the earth’s surface.

Another CO₂ capture technology is gaining interest among scientists and engineers, as well as venture capitalists. It is called Direct Air Capture, or DAC. The process uses industrial-size fans and filters to remove carbon from air. Because the level of CO₂ is evenly distributed throughout the earth’s atmosphere, DAC can be deployed anywhere, independent of sources of emission. That is an important benefit if the objective is to sell the captured gas to users.

Potential markets for captured gas are numerous and varied. A DAC project of Climeworks in Switzerland is selling captured CO₂ to a greenhouse that uses it to make vegetables grow faster. The same facility is negotiating with beverage companies to add carbonization for sparkling water or soda. A company called Newlight uses CO₂ and methane to form a polymer trademarked as AirCarbon, which is being used to make desk chairs and smartphone covers. Another engineering firm, Carbon Engineering, is using CO₂ and hydrogen split from water to produce synthetic fuels for transportation.

Human activity annually releases billions of tons of carbon dioxide into the atmosphere. Much of that is offset by natural processes, prominently represented by the Amazon rain forest. Reducing the annual release of CO₂ is the most important step in reducing atmospheric CO₂.

“Climate experts tell us that, alongside other mitigation solutions, carbon removal technologies like DAC are going to be essential if we hope to decarbonize in time to avoid the worst impacts of climate change,” said Steve Oldham, CEO of Carbon Engineering. To make a significant contribution he says, “These carbon removal technologies need to be deployed widely and at large scales.”