Division of Water Resources Engineering, Faculty of Engineering, Lund University, Lund, Sweden.
Department of Physical Geography and Ecosystem Science, Lund University, Lund, Sweden.
Glob Chang Biol. 2021 Oct;27(20):5154-5168. doi: 10.1111/gcb.15753. Epub 2021 Jul 10.
Stress factors such as climate change and drought may switch the role of temperate peatlands from carbon dioxide (CO ) sinks to sources, leading to positive feedback to global climate change. Water level management has been regarded as an important climate change mitigation strategy as it can sustain the natural net CO sink function of a peatland. Little is known about how resilient peatlands are in the face of future climate change scenarios, as well as how effectively water level management can sustain the CO sink function to mitigate global warming. The authors assess the effect of climate change on CO exchange of south Swedish temperate peatlands, which were either unmanaged or subject to water level regulation. Climate chamber simulations were conducted using experimental peatland mesocosms exposed to current and future representative concentration pathway (RCP) climate scenarios (RCP 2.6, 4.5 and 8.5). The results showed that all managed and unmanaged systems under future climate scenarios could serve as CO sinks throughout the experimental period. However, the 2018 extreme drought caused the unmanaged mesocosms under the RCP 4.5 and RCP 8.5 switch from a net CO sink to a source during summer. Surprisingly, the unmanaged mesocosms under RCP 2.6 benefited from the warmer climate, and served as the best sink among the other unmanaged systems. Water level management had the greatest effect on the CO sink function under RCP 8.5 and RCP 4.5, which improved their CO sink capability up to six and two times, respectively. Under the current climate scenario, water level management had a negative effect on the CO sink function, and it had almost no effect under RCP 2.6. Therefore, the researchers conclude that water level management is necessary for RCP 8.5, beneficial for RCP 4.5 and unimportant for RCP 2.6 and the current climate.
压力因素，如气候变化和干旱，可能会使温带泥炭地的角色从二氧化碳（CO ）汇转变为源，从而导致对全球气候变化的正反馈。水位管理被认为是一种重要的气候变化缓解策略，因为它可以维持泥炭地的自然净 CO 汇功能。人们对泥炭地在未来气候变化情景下的弹性以及水位管理在维持 CO 汇功能以缓解全球变暖方面的有效性知之甚少。作者评估了气候变化对瑞典南部温带泥炭地 CO 交换的影响，这些泥炭地要么未受管理，要么受到水位调节。使用暴露于当前和未来代表性浓度途径（RCP）气候情景（RCP 2.6、4.5 和 8.5）的实验性泥炭地中尺度模型进行气候室模拟。结果表明，在未来气候情景下，所有管理和未管理的系统在整个实验期间都可以作为 CO 汇。然而，2018 年极端干旱导致 RCP 4.5 和 RCP 8.5 下未管理的中尺度模型在夏季从净 CO 汇转变为源。令人惊讶的是，RCP 2.6 下未管理的中尺度模型受益于更温暖的气候，是其他未管理系统中最好的汇。水位管理对 RCP 8.5 和 RCP 4.5 下的 CO 汇功能影响最大，分别将其 CO 汇能力提高了六倍和两倍。在当前气候情景下，水位管理对 CO 汇功能有负面影响，而在 RCP 2.6 下几乎没有影响。因此，研究人员得出结论，水位管理对于 RCP 8.5 是必要的，对于 RCP 4.5 是有益的，对于 RCP 2.6 和当前气候则不重要。
