Trace gas and CO2 contributions of northern peatlands to global warming potential

Among terrestrial ecosystems, northern peatlands are one of the largest reservoirs of carbon that has been taken from the atmosphere, mostly during the Holocene. It is generally assumed that drained peatlands are sources of CO₂ and small sinks of CH₄, whereas those in agricultural use are sources of N₂O. The estimation of carbon budgets of peatlands is hampered by the lack of a general ecosystem model for simulating greenhouse gas budgets on a global scale. Paludification is a process in which peatland vegetation starts to grow on mineral forest soil. In terrestrialization, floating peat spreads out on ponds and small lakes. Long-term forest growth experiments initiated in the 20^th Century provide valuable information on subsequent changes in the vegetation and carbon stocks of drained peatlands. The area of peatlands in agricultural use is diminishing in many countries as a result of actions to cut down agricultural over-production.