U.S. Geological Survey, Western Geographic Science Center, Moffett Field, CA 94035, USA; Deakin University School of Life and Environmental Sciences, Warrnambool, VIC 3280, Australia; University of California Santa Cruz, Santa Cruz, CA 95060, USA.
Deakin University School of Life and Environmental Sciences, Warrnambool, VIC 3280, Australia.
Sci Total Environ. 2021 Jul 10;777:145962. doi: 10.1016/j.scitotenv.2021.145962. Epub 2021 Feb 22.
Restoring and protecting "blue carbon" ecosystems - mangrove forests, tidal marshes, and seagrass meadows - are actions considered for increasing global carbon sequestration. To improve understanding of which management actions produce the greatest gains in sequestration, we used a spatially explicit model to compare carbon sequestration and its economic value over a broad spatial scale (2500 km of coastline in southeastern Australia) for four management scenarios: (1) Managed Retreat, (2) Managed Retreat Plus Levee Removal, (3) Erosion of High Risk Areas, (4) Erosion of Moderate to High Risk Areas. We found that carbon sequestration from avoiding erosion-related emissions (abatement) would far exceed sequestration from coastal restoration. If erosion were limited only to the areas with highest erosion risk, sequestration in the non-eroded area exceeded emissions by 4.2 million Mg CO by 2100. However, losing blue carbon ecosystems in both moderate and high erosion risk areas would result in net emissions of 23.0 million Mg CO by 2100. The removal of levees combined with managed retreat was the strategy that sequestered the most carbon. Across all time points, removal of levees increased sequestration by only an additional 1 to 3% compared to managed retreat alone. Compared to the baseline erosion scenario, the managed retreat scenario increased sequestration by 7.40 million Mg CO by 2030, 8.69 million Mg CO by 2050, and 16.6 million Mg CO by 2100. Associated economic value followed the same patterns, with large potential value loss from erosion greater than potential gains from conserving or restoring ecosystems. This study quantifies the potential benefits of managed retreat and preventing erosion in existing blue carbon ecosystems to help meet climate change mitigation goals by reducing carbon emissions.
恢复和保护“蓝碳”生态系统——红树林、潮汐沼泽和海草草甸——被认为是增加全球碳封存的行动。为了更好地了解哪些管理行动能在碳封存方面带来最大收益，我们使用一个空间明确的模型，在一个广泛的空间尺度（澳大利亚东南部 2500 公里的海岸线）上比较了四个管理情景下的碳封存及其经济价值：（1）管理撤退，（2）管理撤退加堤岸拆除，（3）高风险区侵蚀，（4）中等到高风险区侵蚀。我们发现，避免与侵蚀相关的排放（减排）的碳封存将远远超过沿海恢复的碳封存。如果侵蚀仅限于风险最高的地区，那么到 2100 年，非侵蚀地区的碳封存量将超过排放量 420 万吨。然而，如果中等到高侵蚀风险地区的蓝碳生态系统都遭到破坏，到 2100 年将净排放 2300 万吨。与管理撤退相结合的堤坝拆除是封存碳最多的策略。在所有时间点，与单独的管理撤退相比，拆除堤坝仅额外增加了 1%至 3%的碳封存。与基线侵蚀情景相比，管理撤退情景到 2030 年增加了 740 万吨，到 2050 年增加了 869 万吨，到 2100 年增加了 1660 万吨。相关的经济价值也遵循同样的模式，侵蚀造成的潜在价值损失大于保护或恢复生态系统带来的潜在收益。本研究量化了管理撤退和防止现有蓝碳生态系统侵蚀的潜在好处，以通过减少碳排放来帮助实现气候变化缓解目标。
