Climate change is altering how natural systems operate worldwide and is starting to trigger a cascade of effects, some negative and others surprising. The latest finding shows that plants expanding into the Arctic as a result of warming may create large new carbon sinks, a paradox that could help offset some aspects of climate change.
For years, scientists have warned that greenhouse gas emissions must slow or the planet’s future will be at risk. At the same time, researchers are seeking ways to contain and remove already released gases. A recent study published in Scientific Reports indicates that certain climate-driven changes in natural ecosystems are contributing to this effort.
Peat is a carbon-rich organic material produced when dead plants decompose in waterlogged, oxygen-poor environments. The ecosystems that support peatlands are among the most productive natural carbon sinks on Earth, making them key players in efforts to address climate change and its impacts.
Historically, peat has served many uses. It has powered heating, supported gardening, and even influenced the flavor of whiskey. In peat-fired kilns, barley dries with peat bricks, and when burned with minimal flame, it releases a dense smoke that imparts a distinctive aroma to the seeds as well as to the final product.
In 2018, an international research team collected soil samples at three sites around Isfjorden fjord in Svalbard, Norway. Across all sites, scientists observed mineral soil covered by a thin layer of organic matter rich in carbon captured from atmospheric photosynthesis.
discovery of “protopeat”
The Helsinki-based research group led by Minna Väliranta explored these organic soil deposits. They found deposits composed mainly of algae formed under increasingly warm Arctic conditions, signaling the early stages of peat formation.
“It’s not peat in the full sense yet, but it could be the starting point of peat formation,” explains Väliranta.
Protopeat deposits are drawing global interest. Väliranta participates in a broader project funded by the Natural Environment Research Council, a British institution comparable to the Finnish Academy. The project examines whether global warming could trigger northward expansion of peat vegetation.
This expansion aligns with a broader pattern known as Arctic greening, where shrubs and vascular plants spread into areas previously too harsh for growth, driven by warming temperatures.
“If this process leading to protopeat expands rapidly, it could form an unexpected carbon reservoir or a plant community that helps moderate climate change,” says Valiranta.
“This reservoir was not included in many ecosystem and atmospheric models because it was traditionally assumed new peatlands would not form,” adds the researcher. Climate models are continually updated as new evidence emerges and scientists are just beginning to integrate the role of peatlands into them.
carbon “snatchers”
“The discovery of new carbon sinks may require models to be updated to better predict how ecosystems respond to a warming climate,” notes Valiranta.
Peatlands store carbon by accumulating partially decomposed organic matter such as leaves, branches, fruits, and roots. The molecules involved include lignin, carbohydrates, and fatty acids, all contributing to long-term carbon storage.
Organic matter tends to accumulate in peatlands because long-term biomass production outpaces decomposition in the right conditions. The soil must stay waterlogged for long periods and the preserved organic material must resist decay.
Across the planet, peatlands cover roughly 399 million hectares. During the Holocene, they stored around 644 gigatons of carbon, making them one of the most important reservoirs of carbon in the biosphere. Their importance is underscored by the fact that the atmospheric, soil, water, and living components of the Earth exchange more than one hundred gigatons of carbon each year, while net emissions continue to rise by about six gigatons annually.
Peatlands also influence climate by sequestering carbon and releasing methane, shaping longer-term climate regulation and helping moderate temperature rises over millennia.
Reference note: Nature Scientific Reports 2022. Attribution: researchers from Helsinki and colleagues; broader collaboration supported by international partners.
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