See Carbon Removal Technologies | YC Request for Startups for more details
"Background: A growing amount of research concludes it will be nearly impossible for the world to avoid a dangerous 2˚C rise in global temperatures merely by cutting greenhouse gas emissions, given the concentrations already in the atmosphere and the slow pace at which nations are shifting to clean energy. At this stage, the UN’s climate change panel and other institutions have said various methods of capturing and storing carbon dioxide will be required as well.Y Combinator plans to back carbon removal ventures | MIT Technology Review
The problem is that scientists and companies haven’t yet figured out a way to do so economically at anywhere near the scale required.
“It's time to invest and avidly pursue a new wave of technological solutions to this problem—including those that are risky, unproven, even unlikely to work," Y Combinator said in an announcement on Tuesday. "It's time to take big swings at this.”"