While most people think first of atmospheric carbon emissions from fossil fuels when considering climate change, the planet's soil actually stores more carbon and could become a major source of carbon release or a mitigation tactic in the years ahead. Just how soils store carbon, when and how much they release to the atmosphere, and how to get them to absorb more is the subject of intense research as scientists race to understand the processes at play, predict environmental change and use that knowledge to help heal the planet.