Intact peatlands sequester and store substantial amounts of carbon over the long-term period. However, if these peatlands are drained for various purposes, e.g. peat mining, agricultural use or for forestry, they because significant greenhouse gas sources. In Estonia, there are still large areas, where peat extraction stopped already decades ago, and no significant restoration activities have been implemented. All these areas are significant greenhouse gas sources. Restoring such areas into wetlands may turn these large carbon sources into sinks and mitigate climate change. However, there remains considerable uncertainty whether these sites will become net carbon sinks, and to what degree restoration and management methods affect carbon sequestration efficiency and potential increase in methane emissions.

Our current study focuses on carbon fluxes from abandoned peat extraction site and recently restored peatland in Estonia. Both, the Lavassaare and Ess-soo bogs were used for peat mining and were abandoned more than 30 years ago. Ess-soo bog was successfully restored and rewetted in 2019. However, the Lavassaare site is currently abandoned, with restoration works scheduled to begin in late 2024. Here, we use eddy covariance towers to synthesize the continuous carbon dioxide and methane flux data from both study sites. The eddy towers were installed at the Lavassaare site in September 2022 and at Ess-soo in June 2023. Our results showed that Lavassaare abandoned peat extraction area is still significant carbon source with annual emissions of 125 g CO₂-C m^-2 y^-1 and 1.5 g CH₄-C m^-2 y^-1. Preliminary results from Ess-soo restored bog indicate reduced CO₂ loss and increase CH₄ flux, however the vegetation is still under development. This study shows clearly that abandoned peat extraction sites are continuous carbon sources to the atmosphere, while already simply rewetting these sites could remarkably reduce CO₂ loss.