More volcanism means more carbon in the atmosphere and warmer climates. Likewise, any mechanism that serves to change how rocks chemically erode can reduce carbon in the atmosphere and reduce global temperatures. The breakdown of rocks does more than explain why we have canyons, valleys, and ocean cliffs—this weathering changes Earth’s climate over long time scales. Anything that accelerates the chemical breakdown of rocks over long periods of time—changes in the amount of precipitation, the position of the Earth’s continents, or the topography of the land—can cool the planet.
