EVOLUTION IN ACTION:

Direct air capture startups, with machines that pull CO2 from the air, are being backed by companies like United Airlines. Capitalizing on trees' ability to function as natural carbon capture machines, Reddit's former CEO is now running a company that restores forests on degraded land (and recently raised $30 million in a Series A round of funding). Dozens of other companies are experimenting with farming seaweed, regenerative agriculture, and techniques like spreading crushed rock on the ground. And in the Bay Area, a company called Living Carbon is engineering trees that can capture and store more carbon than typical trees. The startup recently completed a stint at the prestigious tech accelerator Y Combinator.

"Planting trees alone is definitely helpful," says Patrick Mellor, cofounder and chief technology officer at Living Carbon. "But any way that we can improve the total drawdown of carbon dioxide from photosynthesis, and also improve retention of that carbon, are ways to quite greatly increase the total drawdown potential of trees."

If a forest can sequester more carbon than it otherwise would have, it also can help with the challenge of finding enough land for planting trees without competing with other uses such as agriculture. "What can you do so instead of planting 1 trillion trees, you only have to plant, you know, 500 billion?" says Maddie Hall, the company's cofounder and CEO. "Then you have a lot more acreage available for other things."

Tweet   @brothersjudd