Worms are radically changing our forests’ soils and depleting terrestrial carbon stocks. For the past 300 years, a slow-motion invasion has been unfolding under our feet. Year by year, a plethora of invasive earthworms have been quietly burrowing their way through our forests’ leaf litter, grasslands and backyard gardens. Although earthworms are beneficial for growing food, research shows they are harming our forests, and could potentially be contributing to climate change. Earthworms are not native to most of North America. Until about 10,000 years ago, a vast ice sheet covered the northern third of the North American continent. Scientists think it killed off the earthworms that may have inhabited the area before the last glaciation.