There's two times more carbon in the earth's soil than in all of its vegetation and the atmosphere -- combined. Biogeochemist Asmeret Asefaw Berhe dives into the science of soil and shares how we could use its awesome carbon-trapping power to offset climate change. "[Soil] represents the difference between life and lifelessness in the earth system, and it can also help us combat climate change -- if we can only stop treating it like dirt," she says.