Climate change mitigation potential of wetlands and the cost-effectiveness of their restoration
Climate change mitigation potential of wetlands and the cost-effectiveness of their restoration
复制标题
湿地减缓气候变化的潜力及其恢复的成本效益
DOI：
10.1098/rsfs.2019.0129
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发表时间：
2020
期刊：
影响因子：
4.4
通讯作者：
D. Friess
中科院分区：
文献类型：
--
作者：
P. Taillardat;B. S. Thompson;M. Garneau;Karelle Trottier;D. Friess
通过以自然为基础的二氧化碳消除战略以成本效益的方式缓解气候变化，已经获得了大量的政策关注。内陆和沿海湿地(特别是北方、温带和热带泥炭地；冻土带；泛滥平原；淡水沼泽；盐沼和红树林)是最有效的长期天然碳汇。然而，它们也会释放甲烷(CH4)，以抵消它们所封存的碳。在这里，我们对湿地碳动态进行了荟萃分析，以(I)确定它们使用不同的度量和时间范围对气候的影响，(Ii)调查湿地恢复缓解气候变化的成本效益，以及(Iii)讨论它们作为负排放技术纳入气候政策的适宜性。根据指标，湿地可以同时是净碳汇(即北部和温带泥炭地净生态系统碳收支=−28.1±19.13GC m−2 y−1)，但在100年时间尺度上对气候具有净变暖效应(即北部和温带泥炭地持续全球变暖潜力=298.2±100.6 gCO2 eq−1 m−2 y−1)。这种情况造成了人们对湿地对全球气温影响的矛盾心理。此外，我们的综述揭示了记录湿地碳收支的(数量有限的)研究之间的高度异质性。我们证明，到目前为止，大多数沿海和内陆湿地都有净降温效应。这是由于未受干扰的沿海湿地产生的甲烷排放量有限，以及较老的内陆湿地执行的长期碳封存，而不是甲烷在大气中的短暂寿命。对湿地恢复成本与其可以固定的碳量的分析表明，与内陆湿地(4200-49200吨C−1)相比，在红树林等沿海湿地恢复(1 800美元)比在内陆湿地(4 200-49 200吨C−1)更具成本效益。我们建议，对于内陆湿地，优先考虑保护而不是恢复；而对于滨海湿地，保护和恢复可能是缓解气候变化的有效技术。
The cost-effective mitigation of climate change through nature-based carbon dioxide removal strategies has gained substantial policy attention. Inland and coastal wetlands (specifically boreal, temperate and tropical peatlands; tundra; floodplains; freshwater marshes; saltmarshes; and mangroves) are among the most efficient natural long-term carbon sinks. Yet, they also release methane (CH4) that can offset the carbon they sequester. Here, we conducted a meta-analysis on wetland carbon dynamics to (i) determine their impact on climate using different metrics and time horizons, (ii) investigate the cost-effectiveness of wetland restoration for climate change mitigation, and (iii) discuss their suitability for inclusion in climate policy as negative emission technologies. Depending on metrics, a wetland can simultaneously be a net carbon sink (i.e. boreal and temperate peatlands net ecosystem carbon budget = −28.1 ± 19.13 gC m−2 y−1) but have a net warming effect on climate at the 100 years time-scale (i.e. boreal and temperate peatland sustained global warming potential = 298.2 ± 100.6 gCO2 eq−1 m−2 y−1). This situation creates ambivalence regarding the effect of wetlands on global temperature. Moreover, our review reveals high heterogeneity among the (limited number of) studies that document wetland carbon budgets. We demonstrate that most coastal and inland wetlands have a net cooling effect as of today. This is explained by the limited CH4 emissions that undisturbed coastal wetlands produce, and the long-term carbon sequestration performed by older inland wetlands as opposed to the short lifetime of CH4 in the atmosphere. Analysis of wetland restoration costs relative to the amount of carbon they can sequester revealed that restoration is more cost-effective in coastal wetlands such as mangroves (US$1800 ton C−1) compared with inland wetlands (US$4200–49 200 ton C−1). We advise that for inland wetlands, priority should be given to conservation rather than restoration; while for coastal wetlands, both conservation and restoration may be effective techniques for climate change mitigation.