A two-year study in northern Norway shows that elevating groundwater in drained Arctic peatlands significantly reduces carbon dioxide emissions and can even turn the land into a net carbon sink. Researchers at NIBIO's Svanhovd station found that higher water levels limit microbial activity while maintaining low methane and nitrous oxide emissions. The findings highlight potential climate benefits for cold northern farmlands.
Peatlands naturally store vast amounts of carbon due to water-saturated, low-oxygen soils that slow plant decomposition over millennia. Draining these areas for agriculture introduces oxygen, accelerating microbial breakdown and releasing stored carbon as CO2. In northern regions, such as the Arctic, these peatlands remain understudied because of cold temperatures, short growing seasons, and prolonged summer daylight.
To investigate, scientists from the Norwegian Institute of Bioeconomy Research (NIBIO) conducted a field experiment in 2022 and 2023 at their Svanhovd research station in Norway's Pasvik Valley. They used automated chambers to monitor CO2, methane, and nitrous oxide emissions continuously throughout the growing season across five plots simulating typical drained field conditions, varying groundwater levels, fertilizer applications, and harvest frequencies.
"From studies in warmer regions, we know that raising the groundwater level in drained and cultivated peatland often reduces CO2 emissions, because the peat decomposes more slowly," explained NIBIO researcher Junbin Zhao. The study addressed whether higher water levels could make Arctic peatlands climate-neutral, how they affect emissions versus plant uptake, and the roles of fertilization and harvesting.
Results showed that heavy drainage led to high CO2 releases, similar to southern peatlands. However, raising groundwater to 25-50 cm below the surface sharply cut emissions. "At these higher water levels, methane and nitrous oxide emissions were also low, giving a much better overall gas balance. Under such conditions, the field even absorbed slightly more CO2 than it released," Zhao noted. Continuous monitoring captured daily fluctuations and emission spikes often overlooked in sporadic measurements.
The Arctic's cool climate and long light nights amplified benefits: wetter soils reduced oxygen around roots, lowering plant activity but enabling earlier net CO2 uptake each day. Above 12°C soil temperatures, emissions rose due to faster microbial activity. Fertilizer increased grass biomass without altering gas emissions, while frequent harvesting removed carbon from the system, potentially eroding peat over time.
Zhao suggested integrating water management with practices like paludiculture—growing wet-tolerant plants—to sustain biomass production without drying soils. Local variations within fields underscored the need for precise, site-specific strategies in climate accounting. The research appears in Global Change Biology (2025).