快猫短视频

LIKE much of Europe, Finland was left . It needed to ramp up productivity fast and the government decided the answer was forestry, the country鈥檚 . Vast tracts of peatland were drained and trees planted, blanketing the swampy ground that covers nearly a third of the country. 鈥淭hese sites are incredibly carbon rich and often have high levels of biodiversity, but they鈥檙e not always the best for growing trees,鈥� says . Unfortunately, by the time this became clear about half of Finland鈥檚 peatland had been degraded.

Environmentally, this posed a serious problem. Without enough water, layers of peat were exposed and easily eroded, leaching carbon dioxide into the air and adding to global warming. Mets盲hallitus, the group that manages Finland鈥檚 state-owned forests, realised that planting trees in such places was no longer an option. Today, it is committed to a different goal: restoration. 鈥淚f we get the peatlands back underwater, it means the carbon remains in the soil,鈥� says Otsamo, manager for sustainable development at Mets盲hallitus. 鈥淥ver time, the natural vegetation will return, drawing carbon from the atmosphere like a sponge. That鈥檚 what we鈥檙e trying to do now.鈥�

Finland isn鈥檛 alone. Worldwide, about a fifth of peatlands have been drained, burned or otherwise damaged to make way for forests, farms and infrastructure, or extracted as fuel. This degradation generates a whopping . So peatland restoration could play a pivotal role in climate regulation. This realisation is now driving conservation efforts from the Arctic to the tropics.

鈥淧eatland contains twice as much carbon as all the world鈥檚 forests鈥�

Although mostly found in the more northerly reaches of the planet, peatland is present in almost every country. It takes a variety of forms from bogs and moors to swamps and fens, but all are made of partly decomposed organic matter 鈥� mostly from plants 鈥� in waterlogged, low-oxygen, highly acidic conditions. These soils may have accumulated over millennia and can be metres thick, making peatland one of the . Despite covering just 3 per cent of the world鈥檚 surface, it contains nearly a third of all the carbon in soil 鈥� twice as much as is stored in the world鈥檚 forests.

Rapid release

These huge reserves of carbon re-enter the atmosphere at an alarming pace when peatland is drained. 鈥淭he carbon goes in slowly, but comes out fast,鈥� says , secretary-general of the International Mire Conservation Group. 鈥淒amaged peatlands lose around 10 times more carbon than healthy ones can sequester. If the current levels of peatland emissions continue as they are, they will contribute an increase of around 0.1掳C to global temperatures in the coming decades.鈥�

Stalling this is the top priority for peatland conservationists, and UK scientists in Scotland are at the sharp end of global restoration efforts. , 80 per cent of which have been degraded 鈥� in part the result of an ill-fated tree-farming programme in the 1950s. 鈥淭he fundamental aim is to restore the land鈥檚 hydrology,鈥� says ecologist , which manages the country鈥檚 forest estate. 鈥淲e鈥檙e trying to get them to a condition where they mimic peatlands that have never been modified.鈥�

The first step is often to install 鈥減eat dams鈥�, which entails blocking drainage channels to prevent run-off using huge chunks of healthy peat borrowed from a nearby part of the bog. Some locations demand a more intensive approach. Where the terrain is pockmarked with ploughed ridges and furrows, specialised machinery is used to smooth out the ground, reducing the overall surface area. In other cases, restoration teams engage in stump flipping 鈥� crushing excavated tree stumps into the soil upside down 鈥� while backfilling trenches to block subsurface cracks in the peat. 鈥淲ith all of this, the goal is to get the water table high enough for the natural vegetation to return, particularly the peat-building plants,鈥� says McKee.

Of these, the most important are sphagnum mosses. Synonymous with northern peatlands, coppery-green sphagnums carpet the surface, thriving in the low-oxygen, acidic conditions. Highly absorbent, these plants can soak up more than eight times their weight in water, helping to keep the surrounding soil saturated. This, in turn, slows the decay of other plant material 鈥� aided by compounds within the cell walls of the moss. This organic matter compresses downwards over time to form peat. McKee and his colleagues have found that vegetation recovery can be relatively quick, but it takes a minimum of 10 years for a revived bog to stop emitting CO₂.

To date, about 250 square kilometres of degraded Scottish peatland have been put on the road to recovery. The goal is to restore 10 times that area by 2030. If that ambition is to be realised, measuring the success of ongoing restoration projects, and deciding where to site new ones, is fundamental. 鈥淚f we鈥檙e going to be able to restore degraded peatlands, we first need to know where they are, and what state they鈥檙e in,鈥� says . 鈥淟ikewise, with current monitoring programmes, we need to know what effect the work is having.鈥�

鈥淚t takes at least 10 years for a revived peat bog to stop emitting carbon dioxide鈥�

One part of the answer is interferometric synthetic aperture radar, or InSAR. Bouncing radio waves between the surface of Earth and a satellite orbiting about 700 kilometres above, InSAR produces data that, once processed by environmental monitoring firm , can detect changes to the peatland over space and time. This can reveal long-term trends. When peatland is in poor condition, it subsides as a result of water and carbon loss, but as it recovers, the opposite occurs. 鈥� the natural surface motion dynamics of healthy peatland as it swells and contracts in response to different environmental conditions. Such changes are then verified on the ground. 鈥淲e use ground-based data on vegetation, water level, greenhouse gases and management history,鈥� says Andersen, part of a team led by David Large at the University of Nottingham, UK, that pioneered this use of InSAR. 鈥淎ll of this is useful for understanding how 鈥榖og breathing鈥� relates to peatland condition,鈥� says Andersen.

The researchers believe their satellite methodology could, in theory, be applied anywhere. If so, this would address one of the greatest hurdles to global peat restoration efforts: assessing the size and state of peatlands over wide areas, quickly and cost-effectively. However, the use of InSAR will prove more difficult in places where dense vegetation hides the soil surface from the satellite. In South-East Asia, can鈥檛 come soon enough for conservationists in Indonesia, home to a third of the planet鈥檚 tropical peatlands.

Up in flames

The country鈥檚 forests cover tens-of-millions of hectares of peatland, which stores an . Decades of draining and deforestation for oil palm plantations and agriculture have left millions of hectares degraded, releasing huge volumes of CO₂ into the atmosphere. Devoid of water, parts of these damaged peatlands routinely ignite, . When, in 2015, the fires reached their fiercest in living memory, nearly 16 million tonnes of carbon were emitted every day, about the same as the total daily emissions of the US. In response, Indonesia鈥檚 authorities committed to restoring . But that target was missed, .

鈥淭here鈥檚 a lot of work to do, which is why it鈥檚 very important to develop a precise and realistic restoration plan,鈥� says . As with restoration programmes elsewhere, re-wetting is the first priority. Then, when the water table has risen sufficiently, native vegetation can be reintroduced, starting the terrain鈥檚 return to natural function. It isn鈥檛 as simple as it sounds. Considerable fieldwork, often in difficult terrain, is required to determine how badly damaged the peatland is and to understand the distribution and dimensions of the drainage canals that must be blocked to prevent further run-off. Large blocks of concrete or wood are installed in the canals. This isn鈥檛 a foolproof process, says Sari, because the barriers frequently fail to retain the water, which still escapes via underground routes.

There are also economic concerns to contend with. Although crucial environmentally, peatland recovery often means reclaiming land used for agriculture. There is an onus on restoration authorities to address this, identifying and facilitating alternative income streams for local communities, says Sari. Research by WRI Indonesia shows this can be done. 鈥淲e鈥檝e proved that peatland can offer economic value even when it鈥檚 in a healthy, saturated state,鈥� she says. 鈥淔or example, certain species of native crops can grow well in wet conditions, which means 鈥�

These lessons can be applied in other areas of tropical peatland 鈥� some of which have only come to light in recent years (see 鈥�Protecting pristine peatland鈥�). But different solutions are required to tackle a looming crisis in the icy bogs of Earth鈥檚 far northern zones, which hold around 80 per cent of global peatland carbon. Here, much of the peat lies on top of and within permafrost, a layer of perpetually frozen subsurface soil, sediment and rock. For now, this peat is a net store of carbon 鈥� with an estimated , CO₂ escapes into the atmosphere and that is happening far . And rising global temperatures aren鈥檛 the only problem. 鈥淚nfrastructure development by oil and gas companies is leading to huge peatland degradation,鈥� says . 鈥淭his is very dangerous because the peat serves as an insulation material that helps keep the carbon-rich permafrost below zero.鈥�

鈥淏ig industries need to acknowledge and mitigate the damage they are doing to Arctic peatlands鈥�

The problem is particularly acute in Russia where almost half of the country鈥檚 oil and gas fields sit on ecologically sensitive terrain, such as peatlands. There, according to the United Nations, . Minayeva and her team are working hard to restore damaged sites, but, she says, for real progress to be made, the businesses involved must play their part. 鈥淯ltimately, we need the big industries to acknowledge the damage that they鈥檙e doing and mitigate their impact on Arctic peatlands,鈥� she says. 鈥淔or this to happen, we need new regulations.鈥�

Moss transplants

Contrast this with Canada, which is home to more than a , including vast tracts within the Arctic circle. There, regulations require companies operating on peat soils to have a restoration plan. This has proved highly effective. 鈥淲hen I started looking into the emissions from restored peatlands around 20 years ago, I was not optimistic,鈥� says . 鈥淚 am pleased to say that our research has proved me 100 per cent wrong.鈥�

This is largely down to the country鈥檚 pioneering 鈥渕oss layer transfer technique鈥�, . Donor moss 鈥� mostly sphagnum 鈥� is gathered from patches of healthy peatland, then spread by mulching machines over degraded areas. The surface is then blanketed with straw to trap water vapour and keep the moss spores moist. All being well, patches of sphagnum take root after around two years. , Roulet and his colleagues concluded that they become net carbon sinks again after a decade or so. And, 15 years in, the way the ecosystem functions is almost indistinguishable from one untouched by human activity. 鈥淚t鈥檚 impossible to tell that peat has been extracted, until you see the horizon and realise you鈥檙e a little lower than the surrounding land,鈥� says Roulet.

Such success stories are encouraging, but if the world is to veer away from the climate cliff edge, peatland restoration must accelerate. Research published in 2020 concluded that , if it is to stop being a source of CO₂ by the end of the century.

It is a message that is particularly resonant in Finland, a country committed to carbon neutrality by 2035, says Otsamo. 鈥淲e Finns have come on a journey, draining swamps for the good cause of growing trees, and for extraction to sustain local economies. But it鈥檚 clear we need our peatlands healthy again 鈥� for now, and for the future.鈥�

Protecting pristine peatland

Just four years ago, the world鈥檚 largest tropical peat swamp was identified beneath the forests of the Democratic Republic of the Congo (DRC). Covering an area larger than England, the Cuvette Centrale stores some 30 billion tonnes of carbon, making it one of the most . Having only recently been detected, the peatland is pristine; a situation that mustn鈥檛 be allowed to change, say experts.

鈥淔irst and foremost, there is an urgent need for protection,鈥� says Peatlands Initiative of the United Nations. Deforestation poses a major threat. 鈥淲e know that the DRC is preparing a peatlands action plan while also preparing to lift its long-term logging moratorium, which could present challenges,鈥� she says. Trees help keep the terrain wet, providing shade from the fearsome tropical sun. Without the cover of a leafy canopy, tropical peatlands, including the Cuvette Centrale, are at risk of drying out, heightening the danger of fire and carbon outflow.

To address these concerns, in 2018 the DRC, Indonesia and the Republic of the Congo signed the , a pledge to safeguard vulnerable peatlands. Kopansky is also heartened to see that, globally, major corporations and private banks are starting to take investment in peatland protection seriously. 鈥淭he private sector is taking note,鈥� she says. 鈥淲e鈥檙e seeing new sustainable funds emerging that put an emphasis on no deforestation of peat areas, no investment in drainage projects.鈥�

快猫短视频s take samples from the recently discovered Cuvette Centrale peatlands

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