At a greenhouse in La Jolla, California, scientists are trying to harness the carbon-sucking power of plants to clean up the atmosphere. They’re behind the Harnessing Plants Initiative. When carbon isn’t polluting the atmosphere, it’s often in the ground, enriching the soil that plants need to grow. The goal is to genetically modify the plant’s cellular structure. Then the plants will sprout bigger roots, and more of them. And they’ll absorb more carbon.