Half of the world's wetlands are peatlands. Their surface is a layer of peat, which is composed of plant material that has accumulated for thousands of years without decomposing because the environment is saturated with water.
Peatlands are the deposits that contain more carbon in less space in terrestrial zones. Although they only cover about 3% of the terrestrial surface of the planet, they store more carbon than all the biomass of the forests of the Earth.
When peatlands are drained, the peat decomposes, and the carbon is released into the atmosphere as a greenhouse gas. 15% of the world's peatlands have already been drained.
Although these 65 million hectares of degraded peatlands represent less than 0.4% of the earth's surface, they are responsible for 5% of anthropogenic emissions of carbon dioxide.
In contrast, unmanaged peatlands, which cover more than 300 million hectares worldwide, sequester up to 100 megatons of carbon each year. These living peatlands play an important role in regulating the global climate by accumulating carbon in peat soil.
It is possible to significantly reduce greenhouse gas emissions through the requalification and restoration of drained peatlands. Therefore, they can provide other essential ecosystem services such as water retention and services related to biodiversity.
In this context, many conventions around the world are global instruments for the conservation of wetlands. They play an essential role by highlighting the role of peatlands in climate regulation and promoting their conservation and restoration.
Most of these conventions have as their objectives the following aspects:
- To reduce the degradation of peatlands;
- To promote their restoration;
- To improve management practices for peatlands and other types of wetlands that are important greenhouse gas sinks;
- To use peatlands as demonstration sites to raise awareness of the restoration, wise use, and management of peatlands in relation to climate change, habitat protection of specially adapted species and water supply
How are peatlands formed and where are they found?
According to the biome, peatlands can and should be considered zonal or intrazonal soils. Their zonal behavior occurs essentially in the arctic and boreal biomes of the northern hemisphere where they reach their greatest extensions.
In the rest of the planet, they are usually located in low physiographic positions, where there are many marshes, mangroves, etc. However, they can also develop in small endorheic areas, especially in the high mountains.
Under cold climates, a good part of them is formed by the joining of old ponds and lagoons by sediments on which mosses grow well. Under temperate climates (excluding high mountains), usually, they are associated, or, to the edges of the inner lagoons and/or water bodies in peri-coastal environments.
Certain types of hydromorphic forests can give rise to peatlands in temperate and subtropical climates. As landscapes become drier, peatlands begin to become scarce, quartering in certain physiographic spaces in which the factors forming the soil favor their presence.
The origin of all types of coal, and therefore, also of peat, is the anaerobic decomposition of the plant remains buried by sediments. In the most superficial part where these plant residues are affected by anaerobic decomposition, lignin, and cellulose, which are a part of the plant tissues, they are transformed into peat.
It is considered that the peat is Cenozoic coal or, in other words, current coal.
Over time, this same peat, through the sinking caused by the set of physicochemical changes that the sediments undergo since they are deposited until they form a coherent rock, is more compacted and heated and is transformed into lignite.
Types of peat
There are a number of varieties of peat, and we mention a few below:
The base material is the moss of the genus Sphagnum, which is transformed into a product with a very acid pH below 4.5, and poor in ash and nitrogen. It forms the so-called high peatlands of cold and rainy climates.
The preferred one in horticulture is that of Finland.
This type of peat is not formed with Sphagnum, but with other materials. It forms in low peatlands or wetlands with a warmer climate. The resulting product is neutral pH, rich in ash and lignin, and practically has no application in horticulture.
Uses of the peat
As is evident, peat is very good for the environment when used appropriately, and has a lot of applications. Here are a few ways in which peat can be used favorably:
- Fuel: Limited to regions with usable peat and consumed "in situ," for example in Ireland or Scotland where this material is used to dry the whiskey ingredients, which gives it a better aroma.
- Bed of Stall Animals: Also, only in places with peatlands
- Horticulture: The main characteristics of peat are the great water retention capacity, adequate porosity, lack of weed seeds, and stability. Its low pH allows the cultivation of acidophilic plants and can be modified with a mixture. It can be used alone or mixed with other substrates, such as perlite, vermiculite, sand, etc.
- Construction: In regions where wood is scarce, peat has been used to build buildings. In Iceland, for example, it was used in the Middle Age to build houses.
Peatlands have been severely damaged by overexploitation and are threatened by drainage, agricultural conversion and the burning and extraction of fuel, among other factors because of the lack of appreciation and knowledge about this ecosystem. About 15 percent of peatlands have been drained, causing the release into the atmosphere of large amounts of greenhouse gases such as carbon dioxide from the coal stored in soils.
When draining or burning wetlands for agriculture, they go from being a carbon sink to a source that releases centuries of stored carbon into the atmosphere. The CO2 emissions from drained and burned peatlands equal 10 percent of all annual fossil fuel emissions.
Hence, we can, and we must avoid these emissions since we obviously have the knowledge and innovation to do so. We are not tied to preventing or mitigating climate change.