“Protecting 30 percent of America’s natural areas will help stabilize the climate, protect biodiversity, and give plants and wildlife a chance to adapt to the warming already baked into our current climate.” Among the many goals in President Biden’s climate change agenda, protecting 30 percent of U.S. lands and ocean territories by 2030 is among the most ambitious. And among the most complex. The administration initiative is likely to face political headwinds in a divided government. Nevertheless, achieving the “30 by 30” goal could be a critical marker on the road toward a carbon-free future. The reason: Natural landscapes and seascapes are powerful carbon sinks, pulling CO2 from the atmosphere and storing carbon in soil, grasses, shrubs, and trees, coral reefs, sea grasses, and ocean floor sediments.