When Does Peat Form?
Peat bogs are formed in mild and humid climates when the land drainage is so bad that pools of water submerge masses of partially decomposed vegetable matter and prevent complete decay. Peatland features can include ponds, ridges, and raised bogs. The characteristics of some bog plants actively promote bog formation. For example, Sphagnum mosses actively secrete tannins, which preserve organic material.
Sphagnum also have special water retaining cells, known as Hyaline cells, which can release water ensuring the bogland remains constantly wet which helps promote peat production. After being dug out of the bog, the peat is left to dry in the open air. When the water has evaporated it will burn readily. Vast quantities of peat exist in many parts of Europe, North America and northern Asia, but it is normally used as a fuel only in countries or regions where there is little coal. Large quantities are used for fires and ovens in Ireland, Scandinavia and Russia.
Peat is harvested as an important source of fuel in certain parts of the world. By volume, there are about 4 trillion cubic metres (5.2 trillion cubic yards) of peat in the world, covering a total of around 2% of the global land area (about 3 million square kilometres or 1.2 million square miles), containing about 8 billion terajoules of energy. Over time, the formation of peat is often the first step in the geological formation of fossil fuels such as coal, particularly low-grade coal such as lignite.
Most modern peat bogs formed 12,000 years ago in high latitudes after the glaciers retreated at the end of the last ice age. Peat usually accumulates slowly at the rate of about a millimetre per year. The estimated carbon content is 547 GtC (Northern Peatlands), 50 GtC (Tropical Peatlands) and 15 GtC (South America).