If internal combustion was the monumental technological achievement that, over the decades, contributed to climate change, perhaps new technologies can help solve the crisis. The Paris climate talks are crucial not only for forging a political agreement to reduce carbon emissions, but for fostering a political environment that encourages green technology and innovation. U.S. Secretary of Energy Ernest Moniz, speaking in November at the Carnegie Endowment for International Peace, stressed that encouraging climate innovation was an essential component of success. “We are advancing the theme that energy technology innovation, and the resultant cost reductions in energy technology, are ultimately the key to meeting our climate challenges,” Moniz said.

Innovation is not a silver bullet, however. “Neither better technology, nor changing to low-carbon behavior will be sufficient on its own; both will be necessary,” Gregory Nemet, a professor of public affairs and environmental studies at the University of Wisconsin-Madison, told the New Republic. “It’s hard to imagine that technology alone will enable people in the highest per capita emitting countries (e.g. the U.S.) to reduce their emissions by 90-95 percent without substantial changes to how they travel and what they consume.” But while politicians hash out the political framework by which to curb carbon emissions, scientists have been attacking climate change from all directions. Here’s a rundown of some of the innovative solutions researchers are pursuing.

Direct air carbon capture

Carbon dioxide is the world’s biggest global warming villain. Released by the combustion of fossil fuels, it remains in the atmosphere longer than other greenhouse gasses like methane and nitrous oxide. Even if we curb emissions after Paris, the CO2 that’s already been emitted will remain for generations. So, why not simply remove all the carbon dioxide that’s in the air?

Carbon capture and sequestration technologies already exist on the small scale—Nazi scientists developed a way to remove excess CO2 from the air in submarines and the crew of Apollo 13 famously fixed their CO2 scrubbers with duct tape—and nowadays some industrial plants use carbon capture to reduce the amount of CO2 that leaves their smoke stacks. Capturing the CO2 floating freely in the atmosphere is more difficult, but teams around the globe are rapidly developing new air capture systems. Klaus Lackner, a professor at Arizona State University, is working on a plastic resin that pulls CO2 out of the air like an artificial tree. Peter Eisenberger, a scientist at Columbia University, is working on a system the uses amines—already used in power plant smokestacks—to make carbon capture more cost-effective and energy-efficient by recycling the amines and selling the captured carbon.

Captured CO2 is used commercially for everything from adding bubbles to soda to extracting oil from wells. But the demand for CO2 is lower than the total amount available. If direct air carbon capture technology develops further, the captured carbon might be stored in saline aquifers deep in the earth, or in volcanic basalt under the ocean. Some are concerned that sequestered carbon might not stay sequestered; if CO2 leaked into groundwater aquifers it could make those aquifers unsafe for drinking. Gas that leaked back out into the air would be very unlikely to pose any threat to humans but would slowly undo any of the gains from capturing the carbon in the first place.

