In humanity’s battle against man-made climate change, the Earth itself provides one of the most important weapons, a natural system that breathes in Earth-warming CO 2 and exhales oxygen.

Yes, I’m talking about plants, engineered by nature itself over the course of millennia to harness the Earth’s natural conditions to turn sunlight and CO 2 into oxygen and organic matter. Plants are the key to many climate-change-fighting tactics. Want to cut down on the methane gas that’s contributing to global warming? Eat more plants (and fewer farting cows). Want to offset some of the carbon emissions from your airline or consumer retail company? Buy a forest of oxygen-emitting trees. Want to create a natural fuel that won’t puff black clouds full of CO 2 into the air? Consider vegetable oil (or photosynthesizing algae, which isn’t a plant but has a lot in common with them).

Plant biologist Joanne Chory thinks plants can do more. She has studied the genetics of plants at the Salk Institute in San Diego for more than 30 years, and she and the rest of the five-person Harnessing Plants Initiative team are convinced that photosynthesis itself can be exploited to create a biological solution to carbon capture.

Emily Dreyfuss covers the intersection of tech and culture for WIRED.

Engineers have tried to do this with massive machines, to limited effect. “As plant biologists, we just looked at the problem a little differently. We didn’t think of an engineering solution. We didn't think about building a big machine that could suck in air and then capture the CO 2 on a sponge, or whatever. We said, 'That’s what plants were evolved to do,'” Chory says.

Unlike engineered solutions, biology harnesses evolutionary time, because plants have already evolved for 500 million years to be great at sucking up CO 2 . In fact, according to the Salk Institute, every year plants and other photosynthetic life capture 746 gigatons of CO 2 and then release 727 gigatons of CO 2 back. If it weren’t for the 37 gigatons of CO 2 humans also release into the atmosphere annually, the global carbon cycle would be healthy. But, as it stands, each year the Earth is left with 18 gigatons of CO 2 it cannot naturally handle.

Chory believes the key to fixing that imbalance is to train plants to suck up just a little more CO 2 and keep it longer. She is working on engineering the world’s crop plants to have bigger, deeper roots made of a natural waxy substance called suberin—found in cork and cantaloupe rinds—which is an incredible carbon-capturer and is resistant to decomposition. By encouraging plants to have bigger, deeper, more suberin-rich roots, Chory can trick them into fighting climate change as they grow. The roots will store CO 2 , and when farmers harvest their crops in the fall, those deep-buried roots will stay in the soil and keep their carbon sequestered in the dirt, potentially for hundreds of years.

“Every year plants and other photosynthetic organisms take up an incredible amount of CO 2 —like twentyfold more than we ever put up when we burn fossil fuels—but then at the end of the growing season most plants just die, and they decompose, and it goes back up as CO 2 . That's been a real problem,” she told WIRED last week in Vancouver, British Columbia, at the TED 2019 conference, where she received an Audacious Project prize of more than $35 million to scale this project. It was the second-largest donation in the Salk Institute’s history. “We’re going to make them amazing.”

If she and her team can breed these plants and get them into the global agricultural food chain, Chory believes they can contribute a 20 to 46 percent reduction in excess CO 2 emissions annually.

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The benefits don’t stop there, according to Chory. Those roots will very slowly break down and deposit their carbon little by little in the soil. This could reverse some of the human-caused depletion that has removed carbon and other nutrients from the soil due to agricultural practices that “treat soil like dirt,” to quote UC Merced soil scientist Asmeret Asefaw Berhe, who also spoke at TED 2019. Berhe explained that nutrient soil depletion from agriculture has left it less fertile, with fewer nutrients for the plants to absorb from the soil.