Peatlands cover just 3% of Earth but could help stabilize the climate

This story was originally published by Yale Environment 360 and appears here as part of the Climate Desk collaboration.

The Aweme borer is a yellowish-brown moth with an inch-and-a half wingspan. In the often-colorful world of lepidopterology — the study of moths and butterflies — it’s not particularly flashy, but it is exceedingly rare. For decades, entomologists thought the moth lived in the sand dunes and oak savannahs in southern Manitoba and the Great Lakes region. No one really knew. Until 2005, only six specimens from four widely scattered locations in North America had ever been found. Many doubted the moth still existed until one was discovered in a peatland fen in the backwoods of upper Michigan in 2009.

That was a game-changing moment for entomologist Kyle Johnson. His easy-going hunt for P. aweme switched gears into an intense one. Instead of focusing on the sand dunes of upper Michigan and Wisconsin, he and his colleagues put on rubber boots, mosquito jackets, and bug hats, and began squishing through dozens of peatland fens, traveling nearly a thousand miles from the Upper Peninsula of Michigan to eastern Saskatchewan. In all, Johnson and his colleagues spent 123 nights capturing moths at bait stations and netting free-flying adults. In that eight-year search for P. aweme, they added 59 new specimens of the Aweme borer to the list of discoveries. Johnson was delighted, but not surprised, given the number of rare species often harbored by peatland fens.

“Peatlands are highly underrated ecosystems,” Johnson told me when I joined him in the field looking for the same moth and other rarities in a fen in Western Canada. “Like many scientists from other disciplines, entomologists didn’t think to look elsewhere because a lot of them didn’t believe that moths and butterflies, as well many birds and animals, could be peatland specialists.”

Peat is partially decomposed plant material that builds up over decades, centuries, and millennia in oxygen-starved, waterlogged conditions. Representing just three per cent of the world’s landscape, bogs and fens (and to a lesser extent swamps and marshes that accumulate peat) are found around the globe: in Hawaii’s Alaka‘i Swamp, which nurtures some of the rarest plants in the world; in the Rockies, where peatlands at 10,000 feet are home to Ice Age plants; in the Hudson Bay Lowlands and Siberia, the two largest carbon storehouses in the world; and in the Central Congo, where 55,000 square miles of peatland were discovered in 2017.

Small as their footprint is, however, the role they play in climate regulation, water filtration, flood and wildfire mitigation, and as refuges for many newly discovered and critically endangered species is an outsized one that raises serious questions about the ongoing degradation caused by a host of factors. These include climate change, wildfire, roads, energy projects such as the Alberta oilsands, sphagnum peat harvesting for crops and gardens, and peat-mining in countries that continue to burn it for fuel and electricity.

Studies suggest that such exploitation has drained, destroyed or degraded 193,000 square miles of the world’s peatlands, an area slightly larger than the state of California. Still, large swaths of the world’s peatlands remain intact, and successful restoration efforts are well underway.

Humans have been draining peatlands for more than a thousand years to clear bogs for agriculture and to burn peat for fuel. The perception that these wetlands were sources of disease added impetus to the degradation, which continues today in places such as Indonesia, where agribusiness has been draining and burning vast areas of peatlands for oil palm plantations.

“People talk a great deal about reducing emissions by planting trees, but few talk about peatlands because they can’t believe that something so small is so important,” says Dale Vitt, a Southern Illinois University plant biologist who has long been studying peatland ecosystems. “There’s still so much to learn about them, but maybe not enough time to find out because of how quickly we are destroying or degrading them as a warming climate dries them out.”

Peatlands are unrivaled in their ability to regulate climate. One square metre of peatland from the Hudson Bay Lowlands of Northern Canada, the second-largest peatland in the world, holds approximately five times the amount of carbon as one square metre of tropical rainforest in the Amazon. As more peatlands are lost, vast amounts of carbon stored within are released. Siberian peatland fires in 2020 emitted a record 244 million tons of carbon dioxide.

Scientists are increasingly concerned that as temperatures rise and droughts worsen, peatlands could dry out at an accelerating rate and be subject to more wildfires, turning even more of them from carbon sinks to carbon sources. Randy Kolka, a soil scientist with the U.S. Forest Service and his colleagues at the Marcell Experimental Forest in Minnesota, are running experiments in 10 chambers designed to mimic what will happen to peatland ecosystems under various climate change scenarios. They range from no change to a very realistic atmospheric temperature increase of 4 degrees F.

In just three years of tracking changes in plant growth, water and peat levels, microbial activity, fine root development, and other factors that control the movement of carbon into and out of the chamber-enclosed bogs, Kolka and his colleagues have found that the warmed bog plots are quickly making the transition from being carbon accumulators to carbon emitters. Even those that were warmed modestly lost carbon five to 20 times faster than historical rates.

Because peatlands are moist ecosystems, they “are a firefighter’s best friend,” especially as wildfires become more common, according to McMaster University ecohydrologist Mike Waddington. That was underscored in a post-mortem he and post-doctoral students Sophie Wilkinson did on the 2016 Horse River fire in the Alberta oilsands region. Wildfire fighters were initially taken aback by the speed with which the fire moved through an area typically dominated by soggy bogs and fens. But some of those peaty wetlands had been drained in an experiment to grow trees, and thick layers of sphagnum moss-dominated peat — which can hold 16 to 25 per cent of their weight in moisture — were degraded and dried out. Thirsty stands of highly combustible black spruce took over as a warming climate further dried out the region.

Had the fen not been so badly degraded, according to Waddington, the fire may have slowed long enough for firefighters to get better control of it.

As climate change intensifies, countries that have traditionally burned peat for heating homes are under greater pressure to curb the practice. Finland, for example, has 60 power plants that burn peat to provide five to seven per cent of the country’s energy needs. Last year, more than 140,000 Swedes and 82,000 Estonians relied on peat to heat their homes. Peat meets six per cent of Ireland’s heating needs and likely much more than that in the remoter regions of Russia.

Some of the more affluent peat-burning countries like Ireland and Finland are committed to reducing their dependence on turf for energy. But poor countries like Burundi and Rwanda are moving in the other direction because there are no economic incentives for them to shift to wind and solar power. In Rwanda, where more than half of the population lives in poverty, the government opened its first peat-fired power plant in 2016, with a long-term plan to burn peat to generate 20 per cent of the nation’s electricity. Eighteen of the biggest peat bogs in the country are being targeted to meet that goal.

Mining of horticultural sphagnum peat moss, widely used by farmers and gardeners in the United States, is another significant cause of peatland degradation. Canada is the world’s largest exporter of horticultural peat moss, producing 1.3 million metric tons annually. Canada currently has no plans to ban the use of this peat, as Great Britain has vowed to do by 2024 in order to meet its climate change targets and to restore biodiversity.

The ability of peatlands to mitigate flooding was on display in 2013 when an epic flood gushed out of the Canadian Rockies during a heavy rain-on-snow event. Had it not been for the beaver-managed Sibbald mountain fen and the adjoining forests in the Kananaskis region holding back some of the water, several Alberta towns — including Calgary — would have been even harder hit than they were, said John Pomeroy, director of the Global Water Futures Program at the University of Saskatchewan. Nevertheless, it was still the worst flood in Canadian history and one that might have been further mitigated had the city of Calgary not drained most of its peatlands for urban developments.

Scientists are only beginning to discover new roles these soggy ecosystems play, such as providing insulated dens for the Massasauga rattlesnakes of Georgian Bay, Ont.; food and refuge for endangered woodland caribou; and the habitat needed to reintroduce critically endangered species, such as the red wolf and the cockaded woodpecker into peatlands of the Alligator and Pocosin Lakes national wildlife refuges in North Carolina.

Scientists continue to find highly productive peatlands in unlikely places, like the extremely high elevations of the Rocky Mountains. Such high-elevation peatlands cover only one per cent of the land surface in the Beartooth Mountains of Wyoming and one per cent of the San Juan Mountains in Colorado. But in each case, the distinct nature of these mountain fens plays an oversized role in supporting insects, plants, and animals and in storing water and carbon. Eighteen small peatlands inventoried in Wyoming contained 32 threatened plants. Four of them — including the small round-leafed orchid, bearberries and the low blueberry willow — are found nowhere else in the state.

David Cooper is a Colorado State University wetland ecologist who has pioneered research in mountain fens. His research has taken him to the high country of the southern Rockies, the Sierra Nevada, the Cascades, the Carpathian Mountains of Poland and Slovakia, and bofedales, the word they use to describe peatlands that are formed and sustained by groundwater and meltwater from glaciers. Cooper and his colleagues have identified 1,738 peatland fens covering 11,000 acres in the Uncompahgre and Gunnison national forests of Colorado, 90 per cent of which were at elevations ranging from 9,000 to 12,000 feet.

The discoveries continue. In 2018, Patrick Maldowan, an ecologist at the University of Toronto, discovered a carnivorous pitcher plant eating juvenile salamanders in peatlands in Ontario’s Algonquin Provincial Park.

“I’ve travelled the world studying peatlands,” says University of Alberta geochemist and soil scientist William Shotyk. “But there is so much still to be learned.”

The recent loss of peatlands is not as irreversible as the decline of sea ice or the meltdown of glaciers. Scientists estimate that 80 per cent of the world’s four million square kilometers of peatlands are still largely in pristine condition. Many of those that are degraded can be easily and economically restored simply by re-wetting them after donor seeds, sphagnum and other mosses are introduced. Since 2010, Russia has been doing this with the help of Germany to stop the spread of runaway wildfires, especially in Siberia. China has successfully done this in the Zoigê Plateau, the most extensive mountain peatland in the world.

The U.S. Fish and Wildlife Service is now re-wetting the Great Dismal Swamp, a vast peatland along the Virginia-North Carolina border that George Washington and others tried to drain before he became president. More than 150 miles of roads, canals and ditches in the refuge go back to the days of Washington. These and other disturbances have disrupted the natural flow of water, drying out the peat to the point where a single lightning strike from a thunderstorm can light it up.

“Smoldering fires like this burn so deeply that it sometimes takes a tropical storm or even a hurricane to extinguish it,” said hydrologist Fred Wurster of the U.S. Fish and Wildlife Service. “It’s worth the effort of re-wetting it because we not only reduce the amount and severity of wildfire, we also mitigate flooding and keep the carbon in the ground.”

In August, the Mushkegowuk Council of Cree Indians in Northern Canada signed a memorandum of understanding with Parks Canada to set aside 34,749 square miles of sea and shoreline along Hudson and James bays. If the marine conservation area comes into being, it will be the first federally protected area in North America specifically designed to conserve, in part, peatlands.

“It takes a long time for peatlands to form naturally,” says Vitt. “We can try to restore them. But what comes back is often not what was originally there. We’re getting better at recolonizing, but it’s expensive and complicated by the drying that comes with climate change. The best strategy is to protect what we have.”