Suzanne's Mom's Blog

Photo: Photographic/Scenic Ireland/Alamy via the Guardian.
Burning peat increases global warming, which is why commercial operations are closing, but undisturbed bogs have always been great for keeping carbon from the atmosphere.

My father-in-law was in the peat moss business back in the day. The Philadelphia company he worked for and later ran was called I.H. Nestor. It sold peat mostly for agriculture, but you may know that peat was also burned for heat, especially in Ireland. My friend, the late great James Hackett, and his family always heated their home with peat, with unfortunate consequences for their health.

Today’s story is about the historical value of peat bogs, an aspect that has been mostly unrecognized until now.

Chris Mooney writes at the Washington Post, “Long before the era of fossil fuels, humans may have triggered a massive but mysterious ‘carbon bomb’ lurking beneath the Earth’s surface, a new scientific study suggests. If the finding is correct, it would mean that we have been neglecting a major human contribution to global warming — one whose legacy continues.

“The researchers, from France’s Laboratory of Climate and Environmental Sciences and several other institutions across the globe, suggest that beginning well before the industrial era, the mass conversion of carbon-rich peatlands for agriculture could have added over 250 billion tons of carbon dioxide to the atmosphere. That’s the equivalent of more than seven years of current emissions from the burning of fossil fuels for energy.

“ ‘Globally [peatlands] are only 3 percent of the land surface but store about 30 percent of the global soil carbon,’ said Chunjing Qiu, a researcher at the laboratory, a joint institution supported by French government research bodies and the Versailles Saint-Quentin University, and the first author of the study published Friday in the journal Science Advances.

“The new finding of an ‘ignored historical land use emission’ suggests that even now, we lack a complete understanding of how the Earth’s land surfaces are driving and modulating the warming of the planet. … Scientists have long worried about the potential for massive amounts of carbon being released by northern permafrost, where ancient plant remains lie in a kind of suspended animation beneath the surface. But the peat threat is very similar; in fact, peatlands overlap considerably with permafrost regions.

“Peatlands are a particular type of wetland, one in which dead plant matter does not fully decay due to the watery conditions, and thus accumulates.

In its normal state, peat slowly pulls carbon out of the atmosphere — unless you disturb it.

“If a peatland is drained — as has occurred for many centuries to promote agriculture, especially the planting of crops — the ancient plant matter begins to decompose, and the carbon it contains joins with oxygen from the atmosphere. It is then emitted as carbon dioxide, the principal greenhouse warming gas. …

“To try to get around the problem of missing historical records, the new study simulates the Northern Hemisphere (outside of the tropics) over thousands of years to determine where peat would have likely developed. Over time, the computer model will begin to include growing agricultural activities. It can then be used to analyze different scenarios for how frequently such developments may have occurred on peatland.

“In a middle-of-the-road scenario, where humans would have regularly grown crops on peatlands, the study finds that some 70 billion tons of carbon (over 250 billion tons when converted to carbon dioxide) would have been lost from the soil.

“Importantly, the analysis does not cover all the peatlands across the globe: It only considers Northern Hemisphere peatlands from the year 850 CE onward. Massive losses of tropical peat are even now occurring in countries like Indonesia and Malaysia, for instance, so global losses will be higher. …

“The study is ‘a broad modeling approach with many assumptions, which can all be individually questioned and debated,’ added Hans Joosten, who leads a peat research group at the University of Greifswald in Germany. ‘But the overall message that remains is that drainage of only a small part turns the entire northern peatland resource into a net carbon source.

‘Though peatlands indeed are carbon sinks in their pristine state, they should also be seen as carbon bombs, which explode whenever they are damaged. Keep them wet!’ …

“The new work underscores that major gaps remain in how much we know about the human contribution to climate change, even as we are trying to halt it. With poor understanding about peat locations, and poor reporting about land conversion, experts say, many countries can’t fully account for peat emissions even now. That could raise questions about what has been happening in their land-use sector.”

More at the Post, here.

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