Peat soils drained for agriculture and forestry are important sources of carbon dioxide and nitrous oxide. Rewetting effectively reduces these emissions. However, rewetting also increases methane emissions from the soil and, on forestry‐drained peatlands, decreases the carbon storage of trees. To analyze the effect of peatland rewetting on the climate, we built radiative forcing scenarios for tropical peat soils, temperate and boreal agricultural peat soils, and temperate and boreal forestry‐drained peat soils. The effect of tree and wood product carbon storage in boreal forestry‐drained peatlands was also estimated as a case study for Finland. Rewetting of tropical peat soils resulted in immediate cooling. In temperate and boreal agricultural peat soils, the warming effect of methane emissions offsets a major part of the cooling for the first decades after rewetting. In temperate and boreal forestry‐drained peat soils, the effect of rewetting was mostly warming for the first decades. In addition, the decrease in tree and wood product carbon storage further delayed the onset of the cooling effect for decades. Global rewetting resulted in increasing climate cooling, reaching −70 mW (m² Earth)⁻¹ in 100 years. Tropical peat soils (9.6 million ha) accounted for approximately two thirds and temperate and boreal agricultural peat soils (13.0 million ha) for one third of the cooling. Forestry‐drained peat soils (10.6 million ha) had a negligible effect. We conclude that peatland rewetting is beneficial and important for mitigating climate change, but abandoning tree stands may instead be the best option concerning forestry‐drained peatlands.

中文翻译：

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重新湿润可为热带和农业泥炭地带来快速的气候效益，但对林业排水的泥炭地则不

用于农业和林业的泥炭土壤是二氧化碳和一氧化二氮的重要来源。再润湿有效地减少了这些排放。但是，再湿润还会增加土壤中的甲烷排放量，并且在森林排水的泥炭地上，会减少树木的碳储量。为了分析泥炭地湿润对气候的影响，我们建立了热带泥炭土，温带和寒带农业泥炭土以及温带和寒带林业排水的泥炭土的辐射强迫方案。芬兰的一个案例研究还估计了树木和木材产品碳存储在北方森林流失的泥炭地中的影响。热带泥炭土壤的重新润湿导致立即冷却。在温带和北方农业泥炭土壤中，甲烷排放的变暖效应抵消了重新润湿后最初几十年的大部分冷却。在温带和寒带林业排水的泥炭土壤中，重新润湿的效果在最初的几十年中主要是变暖。此外，树木和木材产品碳存储量的减少进一步延迟了数十年冷却作用的开始。全球再润湿导致气候降温增加，达到−70 mW（m²地球）^-1在100年中。热带泥炭土（960万公顷）约占三分之二，温带和北方农业泥炭土（1300万公顷）占冷却的三分之一。林业排水的泥炭土壤（1,060万公顷）的影响可忽略不计。我们得出的结论是，泥炭地重新湿润对于缓解气候变化是有益且重要的，但是放弃林木替代品可能是林业排干泥炭地的最佳选择。