Peat Bogs: Nature’s Best Carbon Capture Systems
March 13, 2023 § 3 Comments
Direct air capture of CO2 (DAC) is all the vogue in carbon capture, with considerable innovation occurring. Nature tried its hand at innovating in the passive DAC space a while back. The public is very familiar with the role of forests. To a lesser degree, also known is the role of oceans as carbon sinks.
But it may surprise many that there is a form of vegetation that does a far better job than trees. Five times better per square meter in places. These are plants in peat bogs, which capture CO2 and transfer it over time to the organic layer below, which results in the material we know as peat. Peat may be classified as a very early form of coal, with as little as 40% carbon. Were it to be subjected to higher temperatures and pressures by being buried under sediment, it would eventually convert to lignite, and thence to bituminous and finally anthracite coal. The last clocks in at over 90% carbon and looks like a shiny black rock. Countries, such as Estonia, which are short of other hydrocarbons, have combusted peat for electricity. In other places, regular folks have retrieved buckets of peat from the bogs and burned them for fuel.
Source: Peat Bogs Wallpapers High Quality | Download Free (yesofcorsa.com)
But it may surprise many that there is a form of vegetation that does a far better job than trees. Five times better per square meter in places. These are plants in peat bogs, which capture CO2 and transfer it over time to the organic layer below, which results in the material we know as peat. Peat may be classified as a very early form of coal, with as little as 40% carbon. Were it to be subjected to higher temperatures and pressures by being buried under sediment, it would eventually convert to lignite, and thence to bituminous and finally anthracite coal. The last clocks in at over 90% carbon and looks like a shiny black rock. Countries, such as Estonia, which are short of other hydrocarbons, have combusted peat for electricity. In other places, regular folks have retrieved buckets of peat from the bogs and burned them for fuel.
Peat bogs comprise only 3% of the surface of the earth, but account for 30% of the land-based stored carbon, which is double that stored by all forests combined. For comparison, forests cover about 31% of the earth’s surface. A recent paper compares carbon storage by trees and peat in boreal forested peatland (peatland that also has partial or complete tree canopy). They estimate that the organic storage is higher in the peat layers than in the trees and subsoil (11.0–12.6 kg m−2 versus 2.8–5.7 kg m−2) over a “short” period of 200 years.
And yet, saving rainforests gets all the ink. Save the peat bog does not have the same ring. And yet, it should. Admittedly, on imagery alone, a bog finds it hard to compete against a rainforest. Cuddly koala bears versus fanged Tasmanian Devils (mind you, as any Aussie knows, real-life koalas are not to be messed with either, and in a further nod to excellent promotion, they are not even bears, they are marsupials, as are kangaroos). And the comparison is not that straightforward, because forests provide other benefits over bogs. In any case, the global warming situation is so dire that this is not an either/or proposition. The purpose of this discussion is twofold. One is to draw attention to peat bogs as at least just as important as forests for preservation and expansion, including the use in carbon offset programs. The other is to delve into the science of why peat moss is more effective than other plant matter in capturing and storing carbon.
Sphagnum mosses are the dominant species in peat bogs. They are specially adapted to thrive in low pH (acidic), anaerobic and nutrient poor waterlogged environments. The bog microbiome (defined as a mix of microbes) plays a critical role in the fate of the Sphagnum. The microbiome is dominated by bacteria, but also has fungi. The microbes are highly specific to the Sphagnum, indicating plant-microbe co-evolution. This specificity is believed to increase the carbon fixation efficiency, and to adapt to changing climatic conditions. An Oak Ridge National Laboratory investigation showed that heat tolerant microbes transferred heat tolerance to the Sphagnum.
A key feature of the low pH and anaerobic environment is that when the mosses die, they sink into the bog and do not decompose, thus retaining the carbon for incorporation into the peat layer. Meanwhile new moss grows above. This unique ecosystem carries on fixing carbon from the atmosphere in a manner far more effective than any other natural means. Yet, possibly through a failure to recognize the value, or through a desire to repurpose the land for commercial interests, many of the peatlands have been drained. In the state of North Carolina, nearly 70% of peatlands were drained, according to a Nature Conservancy report (Afield, Spring 2023), a reading of which was the impetus for this discussion. Drained peatlands cease to be carbon absorbers and become emitters. In the more spectacular instances, fires lit by lightning strikes have burned and smoldered for up to a year, spewing as much as 270 tons of CO2 per day. This duration of a year is not surprising because the fire can go underground, where the fuel is plentiful.
Reforestation is a laudable goal. As is the support of the many ongoing investigations targeting passive and active capture of CO2 from the air. But, equally, restoring peatlands and protecting existing ones ought to be a priority. Nature has already provided an efficient CO2 sponge. We must feed it*. Adopt a bog.
Vikram Rao
* Sat on a fence, but it don’t work, from Under Pressure, by Queen and David Bowie (1981), written by Roger Taylor, Freddie Mercury, David Bowie, John Deacon and Brian May.
Research Triangle Energy Consortium 
Vey interesting. Municipalities pick up vast amounts of yard waste and compost them until most of the carbon is remitted as CO2 (or CO2 and methane if done improperly). Could synthetic bogs be a better solution?
I don’t think so. Peat bogs are all about air capture. Solution to MSW is to capture the methane and convert to something useful such as hydrogen.
Peat bogs enhance the sequestration of carbon by greatly slowing the normal biological degradation (metabolism) of organic matter from dead plants (trees, sphagnum moss, etc) back to CO2. See for instance https://cdnsciencepub.com/doi/10.1139/a05-006#:~:text=Paludification%20is%20the%20accumulation%20of,microbial%20activity%2C%20and%20nutrient%20availability. The article you cite above also discusses paludification (a new word for me -‘the accumulation of organic matter over time, and is generally believed to be caused by increasing soil moisture and Sphagnumcolonization’). Fascinating that peat bogs, with their much higher organic matter soil content, actually decrease tree growth and are therefore drained to release the CO2 and enhance timber production.