Apr 26, 2019 8:00 AM

The Plan to Grab the World's Carbon With Supercharged Plants

Joanne Chory is tackling climate change as a biologist: by engineering plants to grab much more carbon from the air than they already do.

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 CO₂ 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 CO₂ 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 CO₂ 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.

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 CO₂ 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 CO₂. In fact, according to the Salk Institute, every year plants and other photosynthetic life capture 746 gigatons of CO₂ and then release 727 gigatons of CO₂ back. If it weren’t for the 37 gigatons of CO₂ 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 CO₂ it cannot naturally handle.

Chory believes the key to fixing that imbalance is to train plants to suck up just a little more CO₂ 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 CO₂, 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 CO₂—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 CO₂. 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 CO₂ emissions annually.

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.

“I think we can get the plants to help us,” Chory said in conversation with Berhe. She’s banking on the hope that the team’s plants will deposit carbon back into the soil in a way that makes it more fertile. That’s how Chory and the team plan to scale up their solution: by convincing farmers that suberin-rich crops will not only help with climate change but also help feed the growing populations of the world.

And they’ll have to, because farmers are not going to sign on to grow weirdly root-huge plants if doing so hurts their yields.

“These plants will be stronger and more sustainable,” Chory says. “The old adage is, feed the soil not the plant,” she explains, and that’s what the team believes these roots will do.

Right now, the Salk team is at the beginning phases of this project. They’ve identified genetic pathways that control for the three traits they want to bring out in plants: increasing suberin, enlarging root systems, and making the roots grow down deeper into the ground. Now they will begin to test combining those three traits in a model plant called arabidopsis in the lab, before moving on to crop plants like corn, soybean, and rice. They hope to have prototypes of souped up versions of major crops within five years and are already in talks with agricultural companies to partner on testing them.

They plan to combine these traits using traditional plant-breeding techniques first, and possibly down the line use gene editing techniques like CRISPR to accelerate trait adoption. The team is trying to move fast in every way.

And time is off the essence. Not just because the next 11 years may be our last best chance to reverse course away from catastrophic climate change, but because Chory herself is facing a looming deadline.

She has Parkinson’s disease and is growing increasingly symptomatic. “My days are going to be numbered in a way that I can see. So that gives me a sense of urgency,” she says. She plans to spend the rest of her scientific career on this single project to use plants to mitigate global climate change.

For Chory, that’s a big departure from her previous work, which, though instrumental to enabling this current project, was never focused on solving a specific urgent problem. Until now, she’d been doing basic research, contributing to overall human knowledge without any sort of mandate that her discoveries cure a specific ill. All of that work allowed her and the team to reach the insight that plants could be harnessed to help with climate change. But applying that science to solve a specific problem feels very, very different and requires her to step far outside her comfort zone.

Applying for the Audacious Project meant going through months of work with TED and consultants hired to help the project finalists refine their pitch to philanthropists. It meant coming to Vancouver and speaking directly about how her work translates to the real world. The day before her talk, Chory was incredibly nervous. A consultant who worked to prepare her, Chris Addy of Bridgespan Group, said that Chory was probably the most nervous of all eight Audacious Project leads. But she got up there and pitched her vision, because of how much it matters to her.

“She gets notes like, ‘Thank you for saving the world!” says her husband, scientist Stephen Worland, who is CEO of therapeutics company Effector and with whom Chory has two grown children.

“That's why I feel like I have the weight of the world on my shoulders. Five people can't save it,” she says. “But we can be a part of it. I feel really strongly that I want to do that now, because I’m getting to the end of my career, really.”

Her newfound mission means that, as she faces Parkinson’s and the looming end of her career, Chory is working probably more hours than ever before. “My daughter said to me, ‘I never remember you working this hard,’” she says. Then she quickly adds, “That felt like a victory, actually, because I was working pretty hard the whole time they were growing up, but she didn't really miss me.”

Now, without kids in the house, Chory is free to work all the time. Trying to save the world, one deep, fat, waxy plant root at a time.