Peatland carbon – the facts
Demystifying peatland carbon stores, carbon sinks, and other gassy issues
Peatland carbon is indeed very important, and the rest of this post will focus on this topic. But I first want to highlight that peatlands are so much more than just carbon, and we need to always view them through a more holistic lens. These boggy landscapes are important freshwater stores and filters, regulating water flows and providing clean water. In their healthy wet state, peatlands can act as fire-resistant buffers, reducing the spread and severity of wildfires and providing refugia in fire-impacted landscapes. Peatlands around the world are also wildlife havens, providing habitat to myriad species, including large mammals, small amphibians, resident and migratory birds, majestic dragonflies, damselflies and other insects, and a mindboggling number of microscopic creatures living in the plants and peat soils. For these reasons and many more, peatlands deserve our attention and care.
The carbon ‘absorbed’, stored, and cycled by ecosystems has become a hot topic due to increased recognition of the importance of ecosystems for mitigating climate change. Peatlands, forests, and other ecosystems are now considered ‘natural climate solutions’ or ‘nature-based solutions’, as their protection, management, and restoration can help contribute to climate change mitigation. But this specialist field of science – ecosystem carbon cycling or biogeochemistry – can be quite bewildering and it can be too easy to get the terminology and facts a bit mixed up.
To help remedy the situation, here are some key facts on peatland carbon.
1. Peatlands store a large amount of carbon in a relatively small area. Peat soils can store a lot of carbon in a relatively small area due to the high portion of organic matter (mostly dead plants) that gradually builds up to form deep peat deposits, often many meters deep. Globally, peatlands cover only ~3 to 4% of the world’s land surface (forests cover ~31%) but they store almost a third of the world’s soil carbon. In an earlier post, I highlighted that an area of peatland in Canada holds five times the amount of carbon as the same area of land within the Amazon rainforest (the non-peaty parts). This comparison was originally provided by a peaty colleague, and it has since become an often shared peaty fact! While the trees and other plants and lichens in peatlands also store carbon, the majority is stored beneath your feet in wet (or frozen) peat soils.
2. Peatlands are the world’s largest terrestrial ecosystem carbon stores. The world’s peatlands are estimated to store between 415 to 550 billion tonnes of carbon, give or take a ~100 billion tonnes of carbon. Our estimates are still quite rough due to limited data and mapping for some regions (more on data and mapping challenges in a future post). This stored peat carbon as a mass (not a gas!) is roughly equivalent to 30 to 37 years of global industrial greenhouse gas (GHG) emissions. And as you may have already seen elsewhere, the world’s peatlands store twice the amount of carbon as the world’s trees (just the trees – this detail is very important!).
3. Peatlands are persistent long-term carbon sinks, removing around 140 million tonnes of CO2 on average from the atmosphere each year. On an annual basis, peatlands are not the world’s largest carbon sinks – they are actually quite small sinks. The world’s forests are a much larger carbon sink, absorbing around 3.5 billion tonnes of CO2 per year. The key difference is that the carbon absorbed and stored in peat soils stays in the ecosystem for much longer (thousands of years) than the carbon in forests (hundreds of years). Carbon stored in leaves, branches, and roots of trees is returned to the atmosphere more quickly than the carbon in deep peat soils.
4. Peat carbon is very old. The carbon stored in northern peatlands can be up to 10,000 years old and in some tropical peatlands the carbon is much older (e.g., peat started to build up in the Congo ~42,000 years ago).
5. Carbon sequestration in peatlands has cooled our climate. Studies show that the carbon gradually taken from the atmosphere and stored in northern peatlands alone over the past 10,000 years has cooled the climate.
6. Peatlands are naturally gassy ecosystems. Carbon is constantly being cycled within and through peatland ecosystems. While carbon is being absorbed from the atmosphere and converted to plant material that eventually becomes peat soil, it is being simultaneously released to the atmosphere as carbon dioxide and methane (GHGs), or in dissolved, particulate, and gaseous forms in water flowing from the peatland. Peatlands are always breathing, even in the winter months (although much less so in some colder regions). And sometimes peatlands can get very gassy, emitting more methane in warmer and wetter conditions. Whether a peatland is a carbon sink or a source depends on the balance of the gases coming in and out (the fluxes). A peatland can turn out to be an overall carbon sink from one year to the next while still having some very gassy moments!
7. Emissions from drained and degraded peatlands are globally significant. Between 1.3 to 1.9 billion tonnes of CO2 equivalent are released to the atmosphere each year from drained and degraded peatlands (roughly 2 to 4% of all human-caused emissions each year). Most drained and degraded peatlands are carbon sources, as more carbon is released to the atmosphere than is absorbed by plants.
8. Peat carbon is irrecoverable. Peat soils have developed gradually over thousands of years, and it will take hundreds to thousands of years for carbon released today to be added back into these ecosystems. We can restore a degraded peatland to become a carbon sink again, rather than a source, but the climate impact of carbon already released to the atmosphere is irreversible.
Peatland carbon is also affected by permafrost thaw and wildfire but as there is a lot of detail to cover here, these topics will be discussed in future posts. I’ll also be diving into the details of the research supporting all the above peaty facts and issues. Stay tuned!
References
Dargie, G.C., et al. (2025). Timing of peat initiation across the central Congo Basin. Environmental Research Letters, 20, 084080. DOI:10.1088/1748-9326/ade905
Frolking, S. and Roulet, N.T. (2007). Holocene radiative forcing impact of northern peatland carbon accumulation and methane emissions. Global Change Biology, 13: 1079-1088. https://doi.org/10.1111/j.1365-2486.2007.01339.x
Gallego-Sala, A.V., et al. (2018). Latitudinal limits to the predicted increase of the peatland carbon sink with warming. Nature Climate Change, 8, 907-913. https://doi.org/10.1038/s41558-018-0271-1
Harris, L.I., et al. (2021). The essential carbon service provided by northern peatlands. Frontiers in Ecology and the Environment, 20, 4, 222-230. https://doi.org/10.1002/fee.2437
Hugelius, G., et al. (2021). Large stocks of peatland carbon and nitrogen are vulnerable to permafrost thaw. PNAS, 117, 34, 20438-20446. https://doi.org/10.1073/pnas.1916387117
Kuntzemann, C.E., et al. (2023). Peatlands promote fire refugia in boreal forests of northern Alberta, Canada. Ecosphere, 14, e4510. https://doi.org/10.1002/ecs2.4510
Lafleur, P.M., et al. (2003). Interannual variability in the peatland-atmosphere carbon dioxide exchange at an ombrotrophic bog. Global Biogeochemical Cycles, 17, 2. https://doi.org/10.1029/2002GB001983
Leifeld, J., et al. (2019). Intact and managed peatland soils as a source and sink of GHGs from 1850 to 2100. Nature Climate Change, 9, 945-947. https://doi.org/10.1038/s41558-019-0615-5
Lindgren, A., et al. (2025). Massive losses and gains of northern land carbon stocks since the Last Glacial Maximum. Science Advances, 11, eadt6231. DOI:10.1126/sciadv.adt6231
Nelson, K., et al. (2021). Peatland-fire interactions: A review of wildland fire feedbacks and interactions in Canadian boreal peatlands. Science of the Total Environment, 769, 145212. https://doi.org/10.1016/j.scitotenv.2021.145212
Pan, Y., et al. (2024). The enduring world forest carbon sink. Nature, 631. https://doi.org/10.1038/s41586-024-07602-x. Also available at: https://www.fs.usda.gov/nrs/pubs/jrnl/2024/nrs_2024_pan_001.pdf
Strack, M., et al. (2022). The potential of peatlands as nature-based climate solutions. Current Climate Change Reports, 8, 71-82. https://doi.org/10.1007/s40641-022-00183-9
UNEP (2022). Global Peatlands Assessment: The State of the World’s Peatlands.
Xu, J., et al. (2018). Hotspots of peatland-derived potable water use identified by global analysis. Nature Sustainability, 1, 246-253. https://doi.org/10.1038/s41893-018-0064-6
Very interesting!