Peat, also known as turf, a surface layer of soil that consists of partially decomposed vegetation with a soft, spongy texture that has accumulated over thousands of years in peatlands, also called bogs, mires or moors.
There are numerous peatlands around the world, in all sizes, and ranging from the tropical regions to the arctic and from sea level coastlines to high mountains. Peat is formed there under conditions of water logging, oxygen deficiency, high acidity , and nutrient deficiency. In colder climates it is mostly formed from shrubs and sphagnum mosses, whereas in hot and humid regions it is formed from fallen trees and can include mangrove trees. Most peat has an age between 4,000 and 8,000 years, although some has been around for as long as 20,000 years. It can be a first stage in the formation of coal, especially low grade coal such as lignite.
Peat is an outstanding carbon sink, with peatlands being being the largest source of carbon storage on land and storing roughly twice as much as the total of all the world's forests. This is because the plants that grow there, while capturing carbon dioxide through photosynthesis as do other plants, do not fully decompose due to the wet conditions and thus they do not release the carbon that would otherwise be returned to the atmosphere in the form of carbon dioxide.
Peatlands can also serve as important habitats for wildlife, and some are biodiversity hotspots. Moreover, they can be major reservoirs of potable water, and some coastal peatlands function as natural flood control systems.
Peat has long been used by humans as an energy source for cooking and heating. Other uses include horticulture, as a bedding material for farm animals, as a raw material for some industrial processes, as a filtering and absorption material, and as insulation for buildings.
Unfortunately, peat is not a renewable resource, because of its very slow rate of growth and the fact that significant regrowth occurs in only in a fraction of peatlands. Centuries of draining, extraction, and burning has damaged or destroyed many peatlands. Fortunately, there has been growing awareness in recent years about the importance of peatlands, and this has been accompanied by increasing efforts to protect and restore them.