Rewetting drained forested peatlands: A cornerstone of Sweden's climate change mitigation strategy.

Peatland rewetting has developed into a key strategy to limit greenhouse gas (GHG) emissions, enhance carbon uptake, and restore biodiversity. With an increasing political ambition to enhance rewetting across many countries, there is a risk of prioritizing peatlands that are most readily available before the ones that result in the largest climate and biodiversity benefits. Based on the best current understanding, we provide a conceptual model of the climate impact and discuss some key steps of progress needed. We focus on Swedish conditions, but also use relevant studies from similar hydroclimatic conditions elsewhere. We argue that the large political interest and investments now made to rewet large areas of peatlands, in combinations with the many unknowns, make it more important than ever to start new rewetting research studies that includes various key aspects of GHG, hydrology, and biodiversity along large climate, land-use history, and nutrient gradients.