Peat (turf) is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world. By volume, there are about 4 trillion m³ of peat in the world covering a total of around 2% of global land area (about 3 million km²), containing about 8 billion terajoules of energy.

Losing 5% of the 2.7m hectares of peatland in Britain, would equal UK's annual carbon emissions and risk its climate targets (IUCN). The UK is amongst the top ten nations of the world in the peatland area and has 9-15% of Europe’s peatland area.

Environmental and ecological issuesEdit

Because of the challenging ecological conditions of peat wetlands, they are home to many rare and specialised organisms that are found nowhere else. Some environmental organisations and scientists have pointed out that the large-scale removal of peat from bogs in Britain, Ireland and Finland is destroying wildlife habitats. It takes centuries for a peat bog to regenerate.

Recent studies indicate that the world's largest peat bog, located in Western Siberia and the size of France and Germany combined, is thawing for the first time in 11,000 years. As the permafrost melts, it could release billions of tons of methane gas into the atmosphere.

The world's peatlands are thought to contain 180 to 455 billion metric tons of sequestered carbon, and they release into the atmosphere 20 to 45 million metric tons of methane annually. The peatlands' contribution to long-term fluctuations in these atmospheric gases has been a matter of considerable debate.^[1]

Peat drainageEdit

Large areas of organic wetland (peat) soils are currently drained for agriculture, forestry and peat extraction. This process is taking place all over the world. This not only destroys the habitat of many species, but heavily fuels climate change. As a result of peat drainage, the organic carbon that was built up over thousands of years and is normally under water, is suddenly exposed to the air. It decomposes and turns into carbon dioxide (CO₂), which is released into the atmosphere.^[2] The global CO2 emissions from drained peatlands have increased from 1,058 Mton in 1990 to 1,298 Mton in 2008 (>20%). This increase has particularly taken place in developing countries of which Indonesia, China, Malaysia and Papua New Guinea are the fastest growing top emitters. This estimate excludes emissions from peat fires (conservative estimates amount to at least 4,000 Mton/CO2-eq./yr for south-east Asia. With 174 Mton/CO2-eq./yr the EU is after Indonesia (500 Mton) and before Russia (161 Mton) the World's 2nd largest emitter of drainage related peatland CO2 (excl. extracted peat and fires). Total CO2 emissions from the worldwide 500,000 km2 of degraded peatland may exceed 2 Gtons (including emissions from peat fires) which is almost 6% of all global carbon emissions.^[3]

FiresEdit

Peat has a high carbon content and can burn under low moisture conditions. Once ignited by the presence of a heat source (e.g. a wildfire penetrating the subsurface), it smolders. These smoldering fires can burn undetected for very long periods of time (months, years and even centuries) propagating in a creeping fashion through the underground peat layer. Peat fires are emerging as a global threat with significant economic, social and ecological impacts.

Recent burning of peat bogs in Indonesia, with their large and deep growths containing more than 50 billion tons of carbon, has contributed to increases in world carbon dioxide levels. Peat deposits in Southeast Asia could be destroyed by 2040.^[4][5]

In 1997, it is estimated that peat and forest fires in Indonesia released between 0.81 and 2.57 Gt of carbon; equivalent to 13–40 percent of the amount released by global fossil fuel burning, and greater than the carbon uptake of the world's biosphere. These fires may be responsible for the acceleration in the increase in carbon dioxide levels since 1998.^[6][7]

In North America, peat fires have a returning cycle (70–130 years) depending on the recolonization by Black Spruce (Picea mariana). Once a fire has burnt through the area normally hollows in the peat are burnt out, and hummocks are desiccated but can contribute to Sphagnum recolonization.^[8]

More than 100 peat fires in Kalimantan and East Sumatra have continued to burn since 1997. Each year, the peat fires in Kalimantan and East Sumatra ignite new forest fires above the ground.

In the summer of 2010, an unusually high heat wave of up to 40 °C (104 °F) ignited large deposits of peat in Central Russia, burning thousands of houses and covering the capital of Moscow with a toxic smoke blanket. The situation remained critical until the end of August 2010.^[9][10]

ReferencesEdit