Study: Climate warming could curb the thriving of Baltic peatlands
Climate warming may cause peatlands in Estonia and the rest of the Baltic states to shift from vital carbon sinks to emission sources, a study has found.
Peat formation halts in warmer climate conditions, causing bogs to start losing carbon, the fresh study, authored by Latvian and Estonian scientists, finds.
Peatlands are significant reservoirs of carbon. "Wetlands quietly trap carbon for thousands of years, slowing the course of global warming. At the same time, they are very fragile, and their future depends largely on the decisions we make today," said Siim Veski, a geology professor at Tallinn University of Technology (TalTech) who took part in the study.
Together with researchers from the University of Latvia, Veski studied the history of 26 wetlands across Estonia's southern neighbor. The conclusions were clear – peatlands grew fastest and stored the most carbon during cool and moist climatic periods. When the climate became warmer and drier, peat growth slowed down almost completely.
"This is worrying, since according to the forecasts, summers in the Baltic countries are set to become hotter and drier. In the past, conditions like that meant that peatlands deposited little peat, or even lost carbon," Veski noted. Peatlands can be likened to, in his words, the living archives of climate history; among the strongest allies in the fight against climate change and biodiversity loss. For this reason keeping them healthy means a safer future for the entire planet.
What exactly did the study show?
Based on the geological history of Northeastern Europe, including Latvia, it can be stated that during the Holocene epoch there were periods in the Baltic region when the climate was warmer than it is today. Consequently, the aim of the study was to assess the formation and development of peatlands in Latvia during the Holocene, which is characterized by distinct long-term climate patterns.
The researchers analyzed both published and unpublished data from Latvia's bog and raised mire areas. In doing so, they assessed their properties and behavior under past climatic conditions. The results showed that the earliest peatlands, which formed about 11,000 years ago, were bogs. During the Holocene, Latvia's peatlands accumulated an average four-meter-thick layer of organic material, with a maximum depth now exceeding 8 meters in some places.
Peat accumulation was most acute during the early Holocene era (11,700–8,200 years B.P.) and late Holocene era (the last 4,200 years B.P.), which coincided with cool and humid hydroclimatic conditions. The highest rates of peat and carbon accumulation were seen during the late Holocene. The formation of peatlands was most modest during the mid-Holocene (8,200–4,200 years B.P.), when the climate was warmer and drier than it is today.
These findings suggest that long-term warming and drying could, under future climate warming scenarios, significantly slow peat formation and carbon sequestration in Latvia and also across Northern European peatlands generally.
The article presenting the results of the study was published in the scientific journal Catena.
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Editor: Andrew Whyte, Andres Reimann
