Push a metal corer into a peatland and you pull up something remarkable: a dark, dense, sponge-like material made of partly decomposed plants. This peat is rich in carbon. In some places, that peat has been building up for thousands of years. Peatlands are the ecosystems where this happens.
Peat is often associated with the bogs of Scotland or Ireland, but peatlands occur on every continent, from the Arctic to the tropics. They can sit beneath open moorland, under swamp forest or in remote floodplains. What links them is water: in wet, oxygen-poor ground, dead plant material does not fully rot away, so carbon accumulates over centuries and millennia.
