Peat forms in wetland conditions, where flooding obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition.although less-common wetlands including fens, pocosins, and peat swamp forests also deposit peat.
This allows humans to reconstruct past environments and study changes in human land use.
Peat is harvested as an important source of fuel in certain parts of the world.
In a widely cited article, Joosten and Clarke (2002) defined peatlands or mires (which they claim are the same) ..most widespread of all wetland types in the world, representing 50 to 70% of global wetlands.
They cover over 4 million square kilometres [1.5 million square miles] or 3% of the land and freshwater surface of the planet.
Peatlands are adapted to the extreme conditions of high water and low oxygen content, of toxic elements and low availability of plant nutrients.
Their water chemistry varies from alkaline to acidic.Some of the world's largest peatlands include the West Siberian Lowland, the Hudson Bay Lowlands, and the Mackenzie River Valley.There is less peat in the Southern Hemisphere, in part because there is less land.Peatlands occur on all continents, from the tropical to boreal and Arctic zones from sea level to high alpine conditions.Peatlands are areas of land with naturally formed layers of peat.naturally released from the peat, maintaining an equilibrium.