Human pressure affects the climate impact of wetlands

Wetlands can both sequester CO2 and release methane (CH4) into the atmosphere. It is difficult to calculate how the balance between the uptake and emissions of these two greenhouse gases is affected by climate change. A large researcher group that includes participation of the Nordic Centre of Excellence DEFROST have concluded that human activities may influence this balance.
Human pressure affects the climate impact of wetlands

Photo: NordForsk/Terje Heiestad

“Our findings show that the use of the wetlands has a significant impact on their climate footprint. In particular, we have documented that converting wetlands to agricultural land produces an increase of the atmospheric radiative forcing, which in turn entails an increase in global warming,” explains Professor Torben R. Christensen, head of the Nordic Centre of Excellence DEFROST (NCoE DEFROST) and professor at Lund University in Sweden.

The researchers behind the new report, published on 25 March in the prestigious scientific journal, Proceedings of the National Academy of Sciences of the USA (PNAS), are therefore recommending that national authorities draw up new guidelines for regulating managed wetlands with a view to reducing methane emissions. In addition, the report states that the UN’s Intergovernmental Panel on Climate Change (IPCC) should incorporate this new knowledge into its future activities.

“This report is the result of many different activities. Over 40 researchers from 28 different research institutions have studied both natural and managed wetlands in a wide range of climatic regions and ecosystem types. This is another example where the Nordic Top-level Research Initiative has made it possible for Nordic researchers to take part in the largest international research projects, which leads to publication in the scientific journals with the highest impact factor,” states Torben R. Christensen.

PNAS article: The uncertain climate footprint of wetlands under human pressure.


Text: Bjarne Røsjø