Climate change is a normal condition for the Earth and the past record suggests continuous rather than stability. The last 2 million years of Earth history are characterised by a series of cold glacial events with warmer intervening interglacial periods. Peatland expanded and contracted with changes in climate and sea-level. Many current peatland started growth following the warming after the last glacial maximum. The initiation of new preatlands has continued throughout the postglacial period in response to changes in climate and successional change.  

The world's peatlands influence the global balance of three main greenhouse gases (GHG) - carbon dioxide (CO₂), methane (CH₄)  and nitrous oxide (N₂O). In their natural state, peatlands remove CO₂ from the atmosphere via peat accumulation and emit methane. The long term negative effect of  methane emissions is smaller than the positive effect of CO₂ sequestratian. By sequestering and storing an enormous amount of atmospheric CO₂ peatlands have an increasing cooling effect in the same way as in former geological eras, when they formed coal, lignite and other fossil fuels.

When peatlands are disturbed, they can become siginificant sources of carbon dioxide and at the same time do not totally stop emitting methane. Methance may still be released drom drainage ditches and in mining operations from milled peat surfaces and peat stockpiles. Drained peatlands, especially after fertilization, can also become an important source of nitrous oxide. Peatland restoration reduces net GHG emissions to the atmosphere, certainly over the long term.

Peatlands are some of the most important carbon stores in the world. They contain nearly 30% of all carbon on the land, while only covering 3% of the land area. Peatland ecosystems contain disproportionately more organic carbon than other terrestrial ecosystems. Peatlands are the top long term carbon store in the terrestrial biosphere and - next to oceanic deposits - Earth's second most important store. Peatland have accumulated and stored this carbon over thousands of years, and since the last Ice Age peatlands have played an important role in global greenhouse gas balances by sequestering an enormous amount of atmospheric CO₂. Peatland in many regions are still actively aequesterign carbon. However the delicate balance between production and decay easily causes peatlands to become carbon sources following human interventions. Anthropogenic diturbances (especially drainage and fires) have led to massive carbon losses from peatland stores and generated a significant contribution to global anthropogenic CO₂ emissions. Peatland restoration is an effective way to maintain the coarbon storage of peatlands and to re-initiate carbon sequestration.