Freshwater wetland restoration and conservation are long-term natural climate solutions.

Autor: Schuster L; School of Life and Environmental Sciences, Deakin University VIC 3125, Australia. Electronic address: l.schuster@deakin.edu.au., Taillardat P; NUS Environmental Research Institute, National University of Singapore, Singapore 117411, Singapore., Macreadie PI; School of Life and Environmental Sciences, Deakin University VIC 3125, Australia., Malerba ME; School of Life and Environmental Sciences, Deakin University VIC 3125, Australia.
Jazyk: angličtina
Zdroj: The Science of the total environment [Sci Total Environ] 2024 Apr 20; Vol. 922, pp. 171218. Date of Electronic Publication: 2024 Feb 27.
DOI: 10.1016/j.scitotenv.2024.171218
Abstrakt: Freshwater wetlands have a disproportionately large influence on the global carbon cycle, with the potential to serve as long-term carbon sinks. Many of the world's freshwater wetlands have been destroyed or degraded, thereby affecting carbon-sink capacity. Ecological restoration of degraded wetlands is thus becoming an increasingly sought-after natural climate solution. Yet the time required to revert a degraded wetland from a carbon source to sink remains largely unknown. Moreover, increased methane (CH 4 ) and nitrous oxide (N 2 O) emissions might complicate the climate benefit that wetland restoration may represent. We conducted a global meta-analysis to evaluate the benefits of wetland restoration in terms of net ecosystem carbon and greenhouse gas balance. Most studies (76 %) investigated the benefits of wetland restoration in peatlands (bogs, fens, and peat swamps) in the northern hemisphere, whereas the effects of restoration in non-peat wetlands (freshwater marshes, non-peat swamps, and riparian wetlands) remain largely unexplored. Despite higher CH 4 emissions, most restored (77 %) and all natural peatlands were net carbon sinks, whereas most degraded peatlands (69 %) were carbon sources. Conversely, CH 4 emissions from non-peat wetlands were similar across degraded, restored, and natural non-peat wetlands. When considering the radiative forcings and atmospheric lifetimes of the different greenhouse gases, the average time for restored wetlands to have a net cooling effect on the climate after restoration is 525 years for peatlands and 141 years for non-peat wetlands. The radiative benefit of wetland restoration does, therefore, not meet the timeframe set by the Paris Agreement to limit global warming by 2100. The conservation and protection of natural freshwater wetlands should be prioritised over wetland restoration as those ecosystems already play a key role in climate change mitigation.
Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(Copyright © 2024 The Author(s). Published by Elsevier B.V. All rights reserved.)
Databáze: MEDLINE
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