Called “the speed bumps of the ocean,” coral reefs work to shrink and slow waves as they speed toward the shore, helping to protect coastlines around the world from tsunamis, hurricanes and cyclones. Coastal managers protect these habitats through measures like creating marine protected areas. More broadly, scientists and policymakers around the world have suggested and tested a range of solutions for climate change ocean impacts. Few had been scientifically vetted. Until now.
A new study, published in Frontiers in Marine Science, is the first of its kind to assess and compare the potential of the 13 most-discussed ocean-based solutions, instead of studying the effectiveness or the cost of just one measure. Scientists gathered a wide range of options into their assessment, ranging from developing renewable energy to creating marine protected areas to promoting carbon storage in marine plants, in a quest to answer the question: To what extent can the oceans help reduce climate change and its impacts?
The team found that the potential for ocean-based options to address climate change and its impacts is very high, and that combining global and local solutions will yield the greatest benefit. Study co-author and Stanford marine biologist Fiorenza Micheli explains, “we find that all actions have limitations and trade-offs. By systematically assessing each measure across multiple factors, like their effectiveness in addressing climate change impacts, their technical readiness, and any associated benefits or unintended impacts, we provide a transparent and scientifically-vetted approach to creating portfolios of actions”
When choosing the 13 ocean-based solutions, the authors considered old and new technologies, policies and local actions. Each solution in the assessment was rated on feasibility, scale of benefits, cost, governability, and effectiveness related to reducing the three most concerning impacts on the ocean due to climate change: ocean warming, ocean acidification and sea-level rise. To measure the potential of these solutions, each option was then applied to vulnerable ecosystems, namely coral reefs, mangroves, salt marshes, seagrass habitats and the Arctic.
The assessment also compared global and local solutions. On the one hand, global measures showed high potential to effectively address climate-related challenges, but exhibited potentially large negative collateral effects. In contrast to global measures, local measures had multiple benefits beyond the direct benefit of a more stable climate and were considered “low-regret” options, but individually cannot provide adequate solutions worldwide.
For example, conserving and restoring ocean plants like mangroves and seagrasses helps oceans to better absorb carbon dioxide. In addition, this marine vegetation measure also helps to maintain healthy conditions for fisheries and provides a natural water filter. However, its potential to counter climate impacts is constrained because there are only limited ocean areas around the world with vegetated habitats.
Combinations are key
The assessment resulted in five evidence-based key messages to guide ocean-based solutions to address climate change. The most noteworthy key message was that by combining local and global efforts, and including both scientific research and policy, ocean-based solutions could greatly diminish the impacts of climate change on the ocean as a whole.
The study suggests that while trade-offs are involved in each option, it is the combination of measures, both global and local in scale, which will bring major benefits. “Our findings reinforced the fact that, for any lasting solution, there is no one-size-fits-all solution. Success depends on societies’ ability, from local and international levels, to join forces and coordinate actions. Diversity and collaboration are key,” explained Micheli.