Friday, June 5, 2020

The Value of Peatlands

Environmental & Science Education
Climate Change
Global Warming
Edward Hessler

It's so easy to break an ecosystem, and it's so hard to bring it back.--Roxane Andersen, biogeochemist, University of the Highlands (Scotland)

The Flow Country is a peatland in Scotland that is on a tentative United Nations Educational, Scientific and Cultural list to be the first peatland in the world to be designated as a World Heritage Site. The UNESCO description notes that it "is widely considered to be the largest area of blanket bog in the world. ... Covering about 4000 km2 (1500 miles2), the Flow Country is a large, rolling expanse of blanket bog found in Caithness and Sutherland in Scotland. The property encompasses an exceptionally wide range of vegetation and surface pattern types, including numerous pool systems. These features are usually rare and localised but here they are widespread...."

Here is a video of the Flow Country in 5 minutes.

The value of peatlands in the economy of the planet's carbon is not generally realized. According to an essay by Virginia Gewin (Nature) on bringing back the bogs that "peatlands have tremendous value for carbon storage. These areas hold more than one-quarter of all soil carbon, even though they account for only 3% of Earth's land area. Globally, peatlands hold more than twice as much carbon as the world's forests do...."*

However, the Flow Country's bogs have been cut for peat, drained and forested, of all things. This has turned the bogs into a carbon source, largely through fire and the relentless action of oxygen joining with carbon to form carbon dioxide. It turned out that trees do not do well in boggy circumstances and Gewin's essay describes restoration efforts. "The timber is low quality, pockmarked by hungry pests and prone to being blown down.... The harvest costs more than the timber is worth, and because the trees will be either incinerated on site to generate electricity or made into heating pellets, the carbon in the trees will return to the atmosphere."

In Scotland's northern highlands, a large excavator is being used to flatten the land, fill in the drainage ditches and to dig up trees. The goal is to restore "50000 hectares (~123552 acres), mainly on government owned nature reserves and forestry land (by 2020). And it aims to push that total to 250000 hectares (~617763 acres) by 2030."

Dr. Roxane Andersen is one of the researchers whose work is "to determine how best to manage the land for carbon storage." The results are promising and I was very surprised to learn that "patches of restored peatlands, in which trees were simply cut and rolled into the blocked drainage ditches, switched from a carbon source to a carbon sink after 16 years..."  That number can be brought down to 10 years with "more intensive management--such as clearing the carbon-rich trees and branches and flattening the ground."

"The trick," in restoration according to Gewin who interviewed Nigel Roulet (McGill University), "is choosing locations that aren't too degraded and where there is still enough residual peat and plant vegetation." Roulet, went on to say, "'If you nudge systems along, and pamper them through first years of recovery they take off on their own."

But the issue is quickly complicated by the message that one of the large answers to global warming/climate change that we should plant trees. "Last year, a study suggested that Earth's ecosystems could support 1 billion (~247105381 acres) more hectares of forest--and store 25% of the atmospheric carbon pool. ... Scotland planted 11,2000 hectares (27675 acres) of new woodlands in 2018. And in the run-up to last December's UK general election, both the Labour and Conservative parties promised to plant millions more trees each year. These new arboreal ambitions could make it harder for researchers and officials to argue that peatlands are the wrong places for trees."

Peatland restoration at scale is happening at only a few locations worldwide. "In fact, the global total peatland area is decreasing because bogs continue to be drained in the tropics and the land is converted for other uses. If that continues, carbon released from peatlands will help to send the global temperature shooting past the target of 1.5-2 degrees C warming above pre-industrial levels set by the Paris agreement." Re-wetting peatlands has a side effect--"restored wetlands will produce some amount of methane, which is a potent greenhouse gas."  
But there is hope. "(T)his will be more than balanced by the reduction in emissions of carbon dioxide and nitrous oxide." There is a net benefit! Whew. Gewin talked with peatland ecologist Hans Joosten (Uinversity of Greifswald, Germany) who noted that "rather than aiming to turn global peatlands into sinks, a more realistic near-term goal is to make bogs carbon neutral."

As you know there is a target for global temperature increase: 1.5-2 degrees C Currently "peatlands are on track to account for 10-40% of that budget. Hans Joosten said that to keep this from happening "'all drained peatlands in the world have to be re-wetted. No cherry-picking which are easiest, cheapest or most effective any more.'" The United Nations Environment assembly "adopted its first ever peatland resolutuion last year, urging member states to conserve and restore these carbon-rich ecosystems."

Gewin draws our attention to Scotland's advantage over other regions in the world. She notes that "landowners in the sparsely populated Flow Country can still make a living from restored peatlands, typically through tourism related to hunting and fishing. In Indonesia, however, people struggle to find crops that will grow on wet peaty soils and provide livelihoods for residents."

And from the BBC, "The Muslim Clerics Preaching for Indonesia's Peat," a story about "green Islam."

Gewin's essay is 4 pages and includes large photographs and two maps (distribution of peatlands worldwide and the distribution of peatlands in Scotland.

*Minnesota is part of the global carbon storage system contributed by peatlands. It is home to the unique peatlands known as patterned peatlands. This ecosystem comprises more than 10% of the state's land (37% of the naturally stored carbon in Minnesota occurs in this unique ecosystem) and consists of more land than any  state other than Alaska." These peatlands take one's breath away in their beauty and are one of the jewels in the Minnesota Scientific and Natural Areas system.

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