What is a peatland?
A peatland is a unique ecosystem consisting of layers of peat, a natural material formed through the long-term accumulation of partially decomposed plant and organic matter. These layers can reach several metres in thickness. Peatlands cover approximately 3% of the Earth’s surface, and their formation takes thousands of years. Although they can be found all over the world, peatlands are increasingly threatened by the commercial extraction peat, which is used as a fuel source and in horticulture as a growing medium and soil amendment.
Peatlands can be divided into two main types: bogs and fens. Bogs are rain-fed peatlands, while fens are fed by groundwater and surface water and remain in constant contact with the water table.
Why are peatlands important?
Due to their high organic matter content, peatlands are important carbon sinks, storing large amounts of carbon dioxide (CO2) and other greenhouse gases. Through photosynthesis, plants absorb CO2 from the atmosphere, and over time this carbon becomes stored in peat. Although peatlands cover only a small portion of the Earth’s surface, they store around 30% of the world’s soil carbon, making them more effective carbon stores than all other vegetation types combined. It is estimated that one square metre of peatland can store more than one kilogram of CO2 per year.
This vital carbon reservoir can only function effectively when peatlands remain sufficiently wet. When peatlands are drained, often due to human activities such as drainage, agriculture, deforestation, or peat extraction, oxygen penetrates the peat layers and accelerates decomposition. As a result, large amounts of CO2 are released into the atmosphere. Increased greenhouse gas concentrations contribute to global warming and climate change, leading to serious and often irreversible environmental impacts.
Peat has a characteristic sponge-like structure and can absorb up to 13 times its own weight in water. This makes peatlands highly effective natural water reservoirs and plays an important role in flood prevention and water regulation.
Peatlands are also valuable habitats for many rare and protected plant and animal species, including orchids, birds, frogs, and insects. Some of these species depend entirely on peatland ecosystems and are found nowhere else.
Last but not least, peatlands are a rich source of archaeological and historical discoveries. Their high acidity and low oxygen levels help preserve organic materials exceptionally well. As a result, artefacts such as manuscripts, clothing, household objects, and even human remains have been found in remarkably good condition.
Threats to Peatlands
Human activities pose significant threats to peatlands, as they do to many other natural ecosystems. Some of the most important threats include:
Peat Extraction for Commercial Use
As mentioned above, peat is used in horticulture, agriculture, and as a fuel source. Historically, it was particularly valued because it was often cheaper and more readily available than wood.
Land Drainage
The construction of drainage channels and canals to redirect water for agriculture, infrastructure, or other human activities can significantly reduce water levels in peatlands. This leads to the drying and degradation of peat soils, making them more vulnerable to erosion and destruction.
Deforestation
Deforestation can have a severe impact on peatlands. When vegetation is removed, the soil becomes exposed to redirect sunlight, causing it to dry out and increasing the decomposition of organic matter. This process releases more carbon dioxide (CO2) into the atmosphere. Dried peatlands are also highly susceptible to fires, which can spread rapidly and are often difficult to extinguish. These fires release enormous amounts of CO2, further contributing to climate change.
Afforestation
Afforestation, or the planting of trees in areas that were not previously forested, can also negatively affect existing peatlands. Certain tree species consume large amounts of water, which can lower the water table and cause peatland habitats to dry out.
Other Threats
In addition to human activities, peatlands can also be affected by natural factors. These include trampling by animals, particularly large herds, naturally occurring fires, and the spread of invasive plant species, all of which can contribute to peatland degradation.
Peatlands in numbers
- Peatlands cover approximately 3% of the Earth’s land surface, representing more than 3 million km2 worldwide.
- Peatlands store around 30% of world’s soil carbon. One square metre of peatland can store approximately 3 g of CO2 per day, equivalent to 1.13 kg per year.
- Peat accumulates at an average rate of approximately 1 mm per year.
- Around 60% of Europe’s peatlands have been drained.
- Globally, peatlands have declined by approximately 15%, contributing to around 5% of global CO2 emissions caused by human activities.
- Degraded peatlands account for approximately 6% of anthropogenic CO2 emissions, equivalent to around 1.3 gigatonnes of CO2 annually.
