Why protecting peatlands is so crucial to combat climate change
Peatlands are some of the most important carbon-storing habitats on the planet, while also being important for wildlife, recreation and flood prevention. Going peat-free is therefore a great way for gardeners to help the planet. We spoke to the IUCN Peatland Programme to find out more about peat and why protecting peatlands is so vital as we confront the climate crisis.
Peatlands cover just 3% of the Earth’s land surface while holding more than twice as much carbon as all the world’s forests combined. They also play a vital role in reducing flooding by absorbing and storing water from the surrounding landscape, and they provide a home for threatened wildlife, including the curlew, hen harrier and the white-faced darter dragonfly.
We spoke to Dr Helen Harper, Peatland Programme Officer for the IUCN Peatland Programme to learn more about peatland habitats and the unique characteristics of peat soils which gardeners help to protect when they choose peat-free
Can you tell us a little bit about peat and the peatlands it comes from?
Peat is formed over long timescales when plant material partially decays under
Peat
Three main peatland habitat types are found in the UK: fen, blanket bog and raised bog. However, there are many more peatland habitats that can look quite different from each other, from mostly treeless blanket bog in the uplands to fen carrs covered with dense vegetation in the lowlands.
Peatlands cover around 10% of the UK land area and can be discovered in the most remote corners of the country, but also near major centres of human population. As iconic landscapes, peatlands offer breathing spaces for millions of people, support livelihoods and provide a sense of place for many communities. Peat harbours a rich cultural and historic archive with preserved artefacts and a wealth of information about our changing environment and climate. Peatlands are important source catchments for drinking water and also have a role in the regulation of water flows.
Unfortunately, most UK peatlands have been historically managed in a way that has left them in a damaged state, with an estimated 80% in some way degraded. At least 94% of UK raised bogs have been lost entirely due to changing land use, including peat extraction for horticulture. This involves draining the peatland and stripping away the living layer which forms peat.
Springfield Moss peat extraction site in Midlothian, Scotland.
Why are peatlands important for the climate and biodiversity?
Peatlands cover only 3% of the world’s land area, but store at least 550 gigatonnes of carbon globally which is more than twice the carbon stored in all the world’s forests, making peatlands the world’s largest terrestrial carbon stock.
Intact peatlands are carbon sinks, capturing carbon from the atmosphere and storing it in peat. Drained peatlands on the other hand become sources of carbon as their hydrological functioning is damaged – peat decomposes when it is exposed to oxygen and releases stored carbon back into the atmosphere. Restoring the hydrological functioning of degraded peatlands is important to stop the oxidation of degraded peat and restore the ability of peatlands to capture and store carbon.
Peatlands also support a range of species and habitats that depend on their unique conditions, such as carnivorous plants, dragonflies, and Sphagnum mosses. Such species may not be able to thrive elsewhere, and some are of international importance for biodiversity conservation.
Peatlands exist in a mosaic with other habitats, connecting them and contributing to landscape-scale biodiversity.
If peat forms naturally, is it a renewable resource?
Peat forms naturally under the right conditions, in areas where water levels are close to the ground surface. However, peat forms over very long timescales, at a rate of approximately 1mm per year. At this rate, it takes 1,000 years to accumulate 1m of peat!
If a peatland is drained, peat will not accumulate. In the UK, an estimated 80% of peatlands are in some way degraded, which reduces the area suitable for peat accumulation further.
To be a renewable resource, peat would have to be extracted at a lower rate than it can form. With such slow accumulation rates, the renewability of peat is not relevant to the timescales of our modern society and peat should not be considered a renewable resource.
Sharpham peat extraction site in the Somerset Levels, England.
What is ‘blond’ peat and ‘young’ peat and is it ecologically fine to use them for growing plants rather than older peat? If a bog is left to renew for a few years, can you harvest the new peat?
Blond peat (sometimes also called white peat or Sphagnum peat) is the topmost layer of a peat bog. It is made up of partially decomposed Sphagnum mosses and other plants. As it is still in the early stages of decomposition, it is usually light brown or yellowish in colour, fibrous and airy. Blond peat is acidic and low in nutrients.
Young peat is a broader term describing peat at an early stage of decomposition, which usually includes blond peat but can also refer to other fresh peat deposits.
To harvest blond peat, methods like sod-cutting or surface milling are used after the top layer of the bog is drained and cleared. Such methods destroy the functioning of the peatland and are not sustainable.
Even if a peatland is rewetted after harvesting peat, this is an expensive process and the surface vegetation that forms peat will be lost. It may take decades before the peatland can start accumulating peat again, so a few years will not be enough to build blond peat for harvest.
Some countries have lots of peat, so how damaging are the quantities extracted for growing media?
More peat is disappearing than is being formed both globally and in Europe. Regardless of the quantities extracted for horticulture alone, we cannot ignore the fact that enormous losses are also occurring due to unsustainable agriculture and forestry on peatlands.
No peat extraction method is sustainable, because along with peat, peat-forming ecosystems are also destroyed. Furthermore, the area of degraded peatlands that is under restoration back to peat accumulating ecosystems is still negligible compared to the area degraded by peat extraction.
If peat has to be extracted somewhere, for example to allow development, can you use or translocate that to restore peatlands elsewhere?
It may sound like a good idea to use extracted peat for restoration elsewhere, but unfortunately it does not work very well. Peat develops in specific conditions over long timescales. Excavating peat disrupts the structure that has been built up over thousands of years. It also dries the peat, leading to a disruption or loss of established biogeochemical processes within peat, including loss of carbon as the peat exposed to oxygen starts decomposing.
Peatland restoration works best if the hydrological function of a peatland is restored, which allows peat to regenerate again in-situ. Moving peat from one site to another does not re-create the conditions required for restoring the functioning of the peatland.
Is using Sphagnum moss for growing media damaging? Where does this come from?
Sphagnum moss has similar physical properties to blond peat and can be used as a growing medium. How damaging it is depends on how it is sourced.
Sphagnum farming is currently being trialled in the UK. It is a method of re-wetting previously damaged peatlands and growing Sphagnum for harvest, which helps to retain carbon stocks in the peat whilst delivering an economic return for growers.
The Sphagnum Farming UK project trialled growing Sphagnum under a range of cover treatments and solar-powered irrigation regimes and tested the product in growing media. Companies like BeadaMoss® are using sustainably micro propagated Sphagnum grown in glasshouses to develop techniques for producing sustainable Sphagnum growing media as an alternative to peat for use in horticulture.
What about brands that collect peat run off to make compost? Would that happen in healthy peatlands?
Brands like ‘Moorland Gold’ source their peat from filters that remove eroded peat from runoff before it enters reservoirs. The product is marketed as a sustainable, natural and environmentally friendly alternative for gardeners who wish to avoid using excavated peat. However, peat runoff occurs in significant amounts where the surrounding peatlands are damaged or degraded, and unable to effectively absorb rainfall. Drainage, burning and overgrazing can damage surface vegetation and expose bare peat, which is vulnerable to erosion by wind and water. The resulting surface water runoff carries peat sediment into watercourses, where it is harvested from. Healthy, intact peatlands on the other hand absorb and store rainfall and would not produce significant amounts of peaty runoff. Harvesting peat sediment for commercial purposes is a practice that profits from degraded peatlands, and is therefore not sustainable.
What is the future for peat-free horticulture and peatlands?
Fortunately, sustainable horticulture is achievable (and necessary), with huge progress made in recent years. The IUCN UK Peatland Programme publications ‘Peat-free Horticulture – Demonstrating Success’ and its more recent addendum celebrate wide-ranging successes in peat-free horticulture and explore opportunities for a thriving and lasting horticulture industry as well as a rewarding gardening experience. Both publications include case studies from producers, manufacturers and retailers who share their experiences with peat-free growing media and moving towards peat-free gardening.
The Horticultural Trades Association and the RHS are also both committed to a peat-free future.
What we need now is legislation which bans the use of peat in horticulture and properly supports the industry to transition to sustainable alternatives, as the Peat-free Partnership explains.
It is also possible to help peatlands recover where peat has been extracted, by blocking drainage features and reintroducing peat-forming plant species. There are a growing number of projects across the UK and in countries like the Republic of Ireland, Finland and Canada, where these ecosystems are being repaired. With time, investment and patience, the barest, bleakest landscapes can once again store water and carbon and provide a home for nature that we all benefit from.
Bolton Fell Moss National Nature Reserve in Cumbria, England, is an inspiring example of a peatland well on the road to recovery from an industrial peat extraction site to a vibrant wildlife habitat, following extensive restoration and rewetting.