New technology is required to make meaningful progress on climate change. This column will focus on one of those options: decreasing the CO2 already in our atmosphere.
Despite robust efforts to reduce greenhouse gas emissions, current technology does nothing about the carbon dioxide already in the atmosphere and therefore some climate experts argue that carbon dioxide removal efforts will be needed.
One carbon dioxide removal process is called "direct air capture." CO2 is captured from ambient air in a filter using a chemical process. The CO2 would then be removed from the filter and stored. Other technologies capture the carbon dioxide from the air using a liquid instead of a solid sorbent.
One process called "enhanced weathering" involves spreading crushed rock in areas that receive large amounts of rain. Rainwater includes some atmospheric carbon. The chemistry between the rain and silicate rock can form a new hard substance with the carbon locked inside.
Carbon dioxide removal is not without controversy. Skeptics argue that even the most efficient projects can't remove sufficient CO2 to be meaningful globally. Current projects are too expensive to deploy on a large scale. Some opponents are concerned about the unintended consequences of tampering with the chemistry of the atmosphere.
Nevertheless, this area of research will continue to get attention and resources given the strong interest in seeking solutions to climate change.