“BE CAREFUL, THIS REALLY is ankle-breaking stuff,” James Banks says as he steps off the path into a soggy expanse of moss, his boots sinking deep into the green morass. A toppled tree has caught his eye, its root plate a wall of near-black soil rising up from the forest floor. Extending an orange fiberglass probe, Banks pokes at the exposed earth. “That’s peat,” he declares, handing me a lump of sticky soil.

It’s what we’ve come to find on a drizzly November day at Cairnsmore of Fleet, a remote nature reserve in southwestern Scotland where woodland borders a wide expanse of windswept hills that are home to sprawling peat bogs, one of Earth’s greatest climate assets. The bog doesn’t look like much — it’s a muted landscape of brown grasses, dotted with small pools and patches of exposed mud. But there’s more to it than meets the eye: Northern peatlands, found across Europe, Asia, and North America, store more carbon than all the world’s plants combined.

Scottish peatland now accounts for 15 percent of the country’s greenhouse gas emissions.

The problem is that many of them are severely degraded, having been drained to make way for forests, pastures, and other land uses. Upsetting the delicate hydrology of a bog can have disastrous consequences, however, as it typically releases vast amounts of carbon dioxide and methane into the atmosphere. That’s why, instead of acting as a natural carbon sink, Scottish peatland now accounts for 15 percent of the country’s greenhouse gas emissions. Globally, researchers have determined that over a fifth of all wetlands, a category that includes peat bogs, have been lost during the last three centuries.

Scotland hopes to reverse that decline and has emerged as something of a global leader in wetlands restoration. The Scottish government has pledged more than 250 million pounds ($312 million) towards restoring 250,000 hectares of peatland by the end of this decade, part of its strategy to reach net-zero emissions by 2045. Banks, a 53-year-old Englishman with cropped white hair and a salt-and-pepper goatee, has found himself with a major role in that effort. Since December, he’s been teaching the country’s first university course in peatland restoration. Scotland needs an extra 1,500 jobs in the field to reach its climate targets; the course is meant to help fill some of them.

It won’t be easy. The state of Scotland’s bogs is evident in Cairnsmore of Fleet as Banks scouts one of the locations he will use to teach his students how to assess a degraded bog — and, hopefully, how to save it. On a clear day, the granite hill that dominates the reserve affords views across the sea to Ireland. All around it lies the blanket bog we’ve come to survey. Trudging across the rain-soaked foothills, Banks points out the subtle contours of old drainage channels that were dug along what’s now a mature plantation of Scots pine and Sitka spruce, a tell-tale sign of degraded bog. “Presumably, when they planted these trees, they drained it all,” he says.

As we make our way onto the open bog, we stumble across even deeper drains. Some have been dammed up, evidence of a previous attempt at restoration. Peeling back a blanket of bright green moss, Banks reveals a dark patch of degraded peat underneath. It has the fluffy consistency of a muffin, crumbling between his fingers. Healthy peat, he explains, should be dense and sticky, like a chocolate brownie. Afterwards, Banks is careful to replace the moss cover and remove other signs of our visit. “There’s definitely been the case where I thought some of the biggest damage that’s happening to the peat bogs is me stomping all over it,” he says.

He’s joking. But the sentiment hints at the enormous responsibility he feels to get things right as he helps educate the next generation of peatland saviors. “It’s the biggest carbon store that we have. It’s just absolutely vital,” he says. “If we lose our peat bogs — and we are losing them, because they’re breaking down — the effects will be astonishing.”

PEAT BOGS COVER more than a fifth of Scotland’s entire land area, making it one of the countries with the highest concentration of this delicate and long-misunderstood ecosystem. Peat not only stores vast amounts of carbon but also filters rainwater and provides important wildlife habitat. Blanket bog, the most common type found in Scotland, spreads across large swaths of undulating ground, particularly in the northern Highlands. Raised bog, another type found mostly in lowland areas, forms domes of peat above wet hollows or even shallow lakes.

Wherever it occurs, peat consists of dead plants compressed in a spongy, waterlogged layer under a dense cover of highly specialized plants — typically cotton grass or feathery sphagnum moss, the latter greedily soaking up water in its environment and creating the conditions for peat to form in the first place. In the acidic and anoxic soil below, decomposition is slowed almost to a halt, preventing microbes and chemicals from breaking down the organic matter. As the plant cover keeps growing, more dead organic matter — and the carbon it contains — is left behind and absorbed into the peat.

“A lot of peatlands have been degraded simply because there have been people in those landscapes for such a long time.”

Across the northern hemisphere, peatlands have accumulated this way ever since glaciers retreated at the close of the last ice age. “You can see how a tremendous history is laid down, a millimeter a year, for 10,000 years,” Banks says, crouching down low as he pushes his measuring probe several feet into the moss and the soil below.

This history is reflected in Scotland’s culture, where peat has permeated large parts of life for centuries and reached far beyond the topography of its bogs, mires, and moors. Distilleries still dry damp malted barley over fires fueled by slabs of peat, the pungent smoke infusing the resulting whiskey with its characteristic flavor. In many communities, it was long used as fuel for heating and cooking. Crofters, the small-scale farmers common across the Scottish Highlands, used to receive a peat bank — a section of bog from which they could cut their own supply — as part of their tenancy. Nowadays most of the peat still commercially extracted in Scotland ends up as compost. (It has also long been burned in power stations across the sea in Ireland, a practice now on its way out.)

For many decades, British landowners and farmers were encouraged to drain the unproductive, barren landscapes to graze sheep and other livestock. After the Second World War, a timber shortage also spurred government incentives to plant forests across the country, often on peatlands. And large stretches are still regularly burned to help establish heather habitat for grouse, a popular game bird. Across the United Kingdom, where peatlands cover an area larger than Hawai‘i or Massachusetts, more than 80 percent of them are now degraded. Similar stories have played out in countries around the world, from Indonesia to Russia to the United States.

“A lot of peatlands have been degraded simply because there have been people in those landscapes for such a long time,” says Roxane Andersen, a professor of peatland science at the University of the Highlands and Islands.

The problem, she explains, is that once drained or exposed to the elements, the dead plants within the peat release greenhouse gases much faster than they ever sequestered them. In fact, researchers have determined that peatlands have been actively contributing to global warming since the 1960s, when peatland conversion in the tropical regions began in earnest. (Northern peatlands have been drained for much longer and were significantly degraded in many places by the nineteenth century.)

“This is why intervention is really important,” Andersen says. “It’s simple, it’s cost-effective, and we know it works.”

BANKS’ HISTORY WITH PEAT began when he was a university student and would hike through England’s Peak District, a national park of limestone valleys and moorland plateaus hemmed in on three sides by the cities of Manchester, Sheffield, and Leeds. His first impression of the area’s peatlands was less than favorable. Decades of acid rain from the surrounding factories, combined with overgrazing by sheep, had stripped away the protective plant layer and left behind a wasteland. “My understanding then was that peat bogs are horrible places,” Banks recalls. “It’s bare peat, essentially. You just end up wading through mud.”

Years later, that understanding would change. After nearly two decades teaching environmental science at a sixth form college, the English equivalent of high school, Banks decided to move on to pursue more hands-on, outdoor work. He bounced around different jobs for a few years, including as an ecological consultant on peatland restoration projects, allowing him to hone his knowledge of peat’s complex ecology and the ins and outs of restoration. By 2021, he was teaching wildlife conservation at Scotland’s Rural College when his department head floated the idea of a new course in peatland restoration. Banks ran with the idea, pulling together some of the country’s leading peat experts and putting together a syllabus.

“Peatland restoration, in a sentence, is about keeping water on the bog.”

The resulting course, developed in partnership with public body NatureScot, teaches students how to discern different signs of degradation, both from human intervention and natural processes, and introduces them to the prevailing techniques for restoration. In many cases, this primarily involves blocking drainage ditches with dams made from stone, wood, plastic, or even peat itself. But restoration can also involve clearing trees to return woodland to open bog, applying natural textiles to combat erosion, and planting mosses and grasses. Any intervention requires carefully reshaping the landscape in harmony with its hydrology.

“Peatland restoration, in a sentence, is about keeping water on the bog,” Banks says.

The first two classes ran this winter and two more are already planned for later this year; both rounds were heavily oversubscribed. Demand is likely to continue to grow as landowners wake up to the financial opportunity buried within peat. Through a certification scheme supported by the government, restoration projects can earn carbon credits for their emissions savings, which landowners can sell on a voluntary market. For now, Scottish government grants pay for much of the cost of restoration itself — carbon credit prices are still too low to make projects economically viable on their own. But the idea is that prices will rise, and with them the potential to make money.

Though carbon offsets are controversial and viewed by critics as a substitute for more meaningful climate action, this has already spurred a land rush among investors hoping to ultimately cash in. There is now a growing industry of project developers that specialize in peatland restoration — some with students in Banks’s course, where they rub shoulders with estate managers, conservationists, and park rangers. Ed Salter, who works for the Peatland Programme, the independent body that oversees the carbon credit scheme, says the number of certified projects has doubled over the past year to more than 150. “That’s quite a trend,” he says. “It’s only going to [grow] more and more.”

A FEW MONTHS AFTER our first expedition, I join Banks and his students on a sunny March morning at the Mar Lodge Estate, which spans some 72,000 acres of mountains, forests, and rivers at the heart of Cairngorms National Park in the Scottish Highlands. Home to four of the five highest peaks in the UK, the estate was acquired by the National Trust for Scotland, a charity, in 1995 and has since been turned into one of the country’s most ambitious nature-conservation areas.

In addition to its pine woods and heather moors, the estate is home to 13,000 acres of peat in various stages of degradation, steadily leaking carbon into the air. In recent years some of that land has been painstakingly restored to bog under the oversight of Matt Watson, who is in charge of peatland restoration for the entire national park. A trained hydrologist and ecologist, Watson has also, over the past two decades, helped develop many of the techniques now used in peatland restoration, which is why Banks was keen to enlist him for his course.

While the class piles into a minibus, Watson invites me to drive out into the estate in his pickup. We turn off the main road and bounce along a sun-dappled dirt track through the woods and into a glen. Restoring peatland, he tells me, requires not only knowing how to alter the landscape, but a keen eye for the subtle forces that may have shaped and degraded a bog in the first place. Without that, any effort at restoration is bound to fail. “Understanding what you do to fix one of these sites is a bit like a doctor seeing a patient,” he says. “If you’ve got a weeping ulcer on your leg, you can deal with a symptom down there — but if that’s part of a chronic issue with a system, like malnutrition, it’s gonna keep coming back.”

A few minutes later, we park beside a river to hike into a more remote part of the estate, where Watson wants to show off some 200 acres of recently restored peat. Along the way, he stops regularly to quiz Banks’s students, trying to sharpen their eyes for the myriad factors that tend to complicate restoration projects. “Has anyone noticed anything about that patch of ground we just walked across?” he asks on the edge of a small woodland. “A lot of deer dung on that ground back there.” A nearby tree he points out, has been stripped of its bark by antlers. Deer, like sheep and hares, are prone to grazing on the fresh shoots sprouting from rewetted bogs, hindering their growth.

“If you’re planning a restoration project up here, that should probably be ringing some alarm bells,” Watson says.

Shortly after, as we start to ascend a hill, someone spots the brown plumage and prominent white rump of a female hen harrier, a ground-nesting raptor, mid-flight over the ridge. “There you go. That’s another constraint, isn’t it?” Watson pipes up. Hen harriers are endangered, with fewer than 550 breeding pairs left in the country, and any work that could impact them is therefore strictly regulated. “We had a 10-hectare site last year; two teal nested in the middle of it … [and] the whole site basically got shut down,” Watson says to hammer home his point.

“The best chance we’ve got of keeping this carbon in this landscape is to stop it as close to source as possible.”

Even when everything goes according to plan, restoring bogs in remote areas — par for the course with peat — comes with challenges. The site we are standing on is crisscrossed by a sprawling system of gullies and channels up to three meters deep; some have revealed mummified stumps of bog pine estimated to be 7,000 years old. Heavy machinery had to be moved across this treacherous terrain and operated along the gullies’ steep, slippery banks. Workers collected 640 cubic meters of mulch and 140 tons of rock farther down the slope, from where it was flown up the hill by helicopters. The mulch was spread out over exposed patches of peat and covered with textiles to hold it in place until new vegetation can grow. Using the rocks and trucked-in timber, the team also built dozens of wooden and stone dams — not so much to stop the water flow entirely, but enough to keep the peat from being washed off the hill.

“The best chance we’ve got of keeping this carbon in this landscape is to stop it as close to source as possible,” Watson explains. Now, sphagnum moss has returned to small pools across the restored bog, soaking up the water and slowly reverting an entire ecosystem. Our boots are loudly sucked into the rewetted ground as we thread our way between the ponds.

While many of Scotland’s bogs were artificially drained, none of the damage in this case was actually manmade. So how did it end up like this?

“Well, that’s the million-dollar-question, isn’t it,” Watson says with a smirk. “It’s hard to know the answer.” His favored theory is that the Medieval Climate Optimum, a warm period that started in 950 CE, caused the peat to dry and crack, creating micropores that grew into underground pipes within the soil and eventually eroded into open channels. “It might have been two or three-hundred years’ worth of warming a thousand years ago,” he says. “But you never know.”

With even experts like Watson left to guess at the complex interplay of geomorphological, hydrological, and ecological processes involved, much of the restoration work necessarily involves trial and error. After centuries of destroying these ecosystems, we’re still learning how and when to help them recover. That’s why Watson has left parts of the site untouched — he simply hasn’t figured out a way to sensitively restore them yet. Peatland restoration, it turns out, involves a lot of agonizing over whether to do anything at all.

“That big gully system might have taken many hundreds of years, if not a thousand years or more, to get to that stage,” Watson says. Modifying the channel complex could further destabilize it and end up accelerating the peat loss many times over. “In some way, leaving it another thousand years to get twice as bad might be the least-worst option,” he says.

Spending time with Watson and Banks, it becomes clear they are both thoughtful about their own role in altering the landscape, while being undeniably driven by the urgency of their work. The lessons they are imparting about peatlands will, ideally, help Scotland meet its domestic climate goals. But the learnings could also spread much wider: Applications for Banks’s course have come from as far afield as Iceland, Norway, and the Faroe Islands, illustrating a dire need for education in this crucial discipline as more countries tap into peat’s role in mitigating the climate crisis.

In the meantime, the stakes keep rising — a fact that is never far from Banks’s mind. As he reminds me several times, damaged peatlands around the world keep leaking the carbon they have painstakingly accumulated for millennia. “The whole business about peat bogs — it’s a no-brainer,” he says. “We’ve just got to fix them.”