Thread by @JoachimClaudet

🚨Paper Alert🚨

Marine protected areas #MPAs are increasingly promoted as #ocean-based #solution to #ClimateChange, but their contribution to climate change #adaptation and #mitigation remains contentious. Our meta-analysis of 22,403 papers brings clarity. Link below.

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🙈Spoiler alert🙉

#FullyProtected #MPAs can can significantly enhance:

©️ carbon sequestration
🌊 coastal protection
🐟 biodiversity
🐡 reproductive capacity of marine organisms
🎣 fishers’ catch
💰 fishers’ income

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We identified the potential “climate pathways” through which #MPAs could contribute to #ClimateChange #mitigation and #adaptation. First along mitigation and adaptation dimensions, and then distinguishing among #ecological and #social dimensions of adaptation.

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We then carried out a systematic literature #review and summarized the results of all empirical studies documenting #MPA outcomes on these climate pathways using both vote-counting and a #MetaAnalytical approach.

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The systematic literature review on #MPA effects on #climate pathways generated a total of 22,403 publications of which 378 were included in vote counting, providing insights from 241 different #MPAs.

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Publications were unevenly distributed among continents, with most #ecological adaptation pathways studied in #Europe and most mitigation and #social adaptation pathways studied in #Asia.

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We investigated the effects of conservation on the Carbon (C) #sequestration capacity of 6 marine C sinks: 3 Blue Carbon ecosystems (#mangrove, #TidalMarsh and #seagrass), recognized by @IPCC_CH for C accounting schemes, as well as #sediments, #macroalgae and #fish.

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Significant increases in C sequestration were found in preserved or restored #seagrass and #mangrove in comparison to similar areas undergoing human pressures. Similarly, untrawled #sediments sequestered significantly more C than areas exposed to trawling.

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Major knowledge gaps remain on how conservation affects #macroalgae living biomass and thus their contribution to C sequestration.

Further research is needed to quantify the exportation rates of organic C from #fish biomass towards #sediments.

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#MPAs contribute to #ecological #adaptation by increasing biodiversity levels, reproductive output and coastal protection compared to unprotected sites.

🧵(10/17)

#MPAs had a majority of positive outcomes across all #social #adaptive pathways (except social organization):

🎣#CPUE
💰#income
🧐environmental #awareness
🤝#participation
👩🔧alternative #livelihoods

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Across all 4 pathways, only #full and #high levels of protection resulted in #mitigation or #adaptation benefits. In contrast, low levels of protection generated no benefits.

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↗️ in species richness and in fishers’ income only occurred for #FullyProtectedAreas, where no fishing is allowed.

↗️ in CPUE also achieved by #HighlyProtectedAreas, where low-impact fishing is allowed only if a #FullyProtectedArea was also present in the #MPA.

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Clear signal that #ProtectionLevel should take precedence in #MPA design in stark contrast to current paradigm of ocean protection globally, with proportion of fully and highly protected MPAs plummeting as countries have rushed to meet conservation commitments.

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The diverse effects of MPAs on #social #organization and #agency of coastal communities underscore that #governance is a fundamental factor in determining whether #MPAs will enhance or impede social #adaptation.

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Our synthesis provides empirical evidence that #MPAs contribute to #ClimateChange #mitigation and #adaptation, particularly when #fully protected, making them a key tool for achieving the goals of the UN Sustainable Development Agenda and the Paris Climate Agreement.

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This work is the first chapter of @JJacquemont's PhD, in collaboration with the @ocean_climate platform, and published in @OneEarth_CP. Watch-out for more papers to come on #MPAs.

📖🔗#OpenAccess: doi.org/10.1016/j.onee…

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