They represent only 3% of the Earth's surface but are one of the largest natural carbon reservoirs in the world. Peat bogs store 30% of soil CO2. These wetlands store carbon thanks to sphagnum, a kind of plant moss, which is found at the root of the peat. Sphagnum moss has a high capacity for carbon capture. Conversely, if they are degraded, peatlands can reject the carbon that was used in the past.