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In a world that grows ever warmer and ever more degraded by human activities, scientists and policy makers have watched with unease as the triple crises of climate change, biodiversity loss, and the decline of ocean health have reinforced each other in a downward spiral. Each of the three crises makes the other two worse. For example, warming oceans have intensified marine biodiversity loss, and declining ocean health amplifies that loss. But science also shows that improving any of these three systems can help to strengthen the others. Increased biodiversity, for example, lends resilience to ocean ecosystems weakened by warming. Recognizing that each of these issues impact each other means that we can begin to pinpoint policy changes and governmental actions that treat these three problems as one.

First and foremost, we must slow and reverse climate change to save our oceans from warming and acidification. In turn, if we proactively defend our oceans, they can provide solutions to climate change through storing excess carbon and providing animal protein alternatives to greenhouse gas-emitting farm animal production. We also know that if we can sustain and restore robust biodiversity and habitat for marine life, oceans are more resilient to changing climate and temperatures. Climate, oceans and biodiversity are related problems and—if addressed together—can offer connected solutions.

Several notable reports show us the science behind the triple crises; and more importantly, offer a roadmap to the connected solutions we must take soon if we are to preserve a habitable, though changed planet. Two reports, the IPBES Global Assessment on Biodiversity and Ecosystem Services [i]  and the Intergovernmental Panel on Climate Change (IPCC) Special Report on Oceans and Cryosphere [ii], provide a wealth of details on the loss of species from human extraction, habitat destruction and climate change and reams of data about the impacts of climate change on the health of our oceans and marine life. To highlight a few conclusions about the oceans from the IPCC report:

“It is virtually certain that the global ocean has warmed unabated since 1970 and has taken up more than 90% of the excess heat in the climate system (high confidence). Since 1993, the rate of ocean warming has more than doubled (likely). Marine heatwaves have very likely doubled in frequency since 1982 and are increasing in intensity (very high confidence). By absorbing more CO2, the ocean has undergone increasing surface acidification (virtually certain). A loss of oxygen has occurred from the surface to 1000 m (medium confidence).”

IPCC, pg 9.

“Since about 1950, many marine species across various groups have undergone shifts in geographical range and seasonal activities in response to ocean warming, sea ice change and biogeochemical changes, such as oxygen loss, to their habitats (high confidence). This has resulted in shifts in species composition, abundance and biomass production of ecosystems, from the equator to the poles. Altered interactions between species have caused cascading impacts on ecosystem structure and functioning (medium confidence). In some marine ecosystems species are impacted by both the effects of fishing and climate changes (medium confidence).”

IPCC, pg 12.

“Climate conditions, unprecedented since the preindustrial period, are developing in the ocean, elevating risks for open ocean ecosystems. Surface acidification and warming have already emerged in the historical period (very likely). Oxygen loss between 100 and 600 m depth is projected to emerge over 59–80% of the ocean area by 2031–2050 under RCP8.5 [the high emissions scenario]  (very likely). The projected time of emergence for five primary drivers of marine ecosystem change (surface warming and acidification, oxygen loss, nitrate content and net primary production change) are all prior to 2100 for over 60% of the ocean area under [high emissions scenario] and over 30% under [lower emissions scenario] (very likely).”

IPCC, pg 19.

To highlight a few conclusions about the oceans from the IPBES biodiversity report:

“Nature across most of the globe has now been significantly altered by multiple human drivers, with the great majority of indicators of ecosystems and biodiversity showing rapid decline. Seventy-five percent of the land surface is significantly altered, 66 per cent of the ocean area is experiencing increasing cumulative impacts, and over 85 per cent of wetlands (area) has been lost….Approximately half the live coral cover on coral reefs has been lost since the 1870s, with accelerating losses in recent decades due to climate change exacerbating other drivers.”

IPBES, pg 11.

“Human actions threaten more species with global extinction now than ever before. An average of around 25 per cent of species in assessed animal and plant groups are threatened suggesting that around 1 million species already face extinction, many within decades, unless action is taken to reduce the intensity of drivers of biodiversity loss. Without such action, there will be a further acceleration in the global rate of species extinction, which is already at least tens to hundreds of times higher than it has averaged over the past 10 million years.”

IPBES pg 12.

Admittedly, this picture looks grim for us, our children and wildlife, but there are many things we can do now to tackle climate change, loss of species and ocean decline. Three recent reports contain dozens of important policy suggestions and changes that we and our governments can make to slow and reverse climate change and biodiversity loss. These reports are: the House Select Committee on Climate Crisis [iii] , the  High Level Panel for a Sustainable Ocean Economy; Climate Solutions [iv] and the Ocean Climate Action Plan [v].

The House Select Committee report makes a host of recommendations about the oceans to maximize their contribution to reducing climate change and its impacts, including:

  • Restoring lost and degraded wetlands, mangroves, and seagrass areas to increase the storage of blue carbon,
  • Using the oceans to produce much more renewable energy with a large increase in wind energy and other forms while protecting marine life,
  • Reducing fossil fuel use in ocean shipping and port activities, and
  • Conserving at least 30% of U.S. oceans in marine protected areas by focusing on areas with high ecological, biodiversity, and carbon sequestration value.

The climate solutions report from the High Level Panel for Sustainable Ocean Economy evaluates the “potential for ocean-based actions to contribute to reducing greenhouse gas emissions.” Rather than merely seeing the ocean as a victim of warming, acidification and sea level rise, this report investigated tangible ways that the ocean—and activities on the ocean—can actively contribute to solving the climate crisis. The report finds that ocean solutions can reduce emissions by 4 billion tons/year by 2030 and 11 billion tons/year by 2050, compared to business-as-usual emissions. This is as much as all the current coal power plant emissions in the world, or the entirety of China’s emissions in 2014. If achieved, the ocean could account for about 20-25% of the emission reductions we need to keep global temperatures from exceeding breaking points (1.5-2.0 degrees C). Nature-based solutions are important in this mix of recommendations, including:

  • Better protection for coastal ecosystems like mangroves, salt marsh, seagrass, and seaweed beds from human destruction to provide Blue Carbon habitats for long term carbon storage.
  • Creating financial incentives and payments for preserving and restoring Blue Carbon habitats, and
  • Including these nature-based solutions in the national commitments that countries make for the Paris Climate Agreement and other international agreements.

Finally, the Ocean Climate Action Plan produced by the Monterrey Institute and Blue Frontier, calls for programs and financing to help coastal communities adapt to the impacts of climate change and implement new ways to manage or use the oceans that would reduce emissions or store more carbon. These ideas mesh well with similar ones from the High Level Panel.

Though recent reports of biodiversity loss and ocean climate change seem grim, the ocean may well be our greatest source of hope. When seen as active solution to climate change—able to contribute an important share of the emission reductions and carbon storage that will be required to keep our planet from exceeding important temperature limits—it is clear that the ocean is not only a victim of downward spiraling forces, but a potential agent of real change.

For these benefits, we must act decisively and soon. If we properly defend the ocean, it will continue to be a source of wonder, food, and vital climate moderation for us and our descendants on this blue planet.


[i] IPBES (2019): Summary for policymakers of the global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. S. Díaz, J. Settele, E. S. Brondízio E.S., H. T. Ngo, M. Guèze, J. Agard, A. Arneth, P. Balvanera, K. A. Brauman, S. H. M. Butchart, K. M. A. Chan, L. A. Garibaldi, K. Ichii, J. Liu, S. M. Subramanian, G. F. Midgley, P. Miloslavich, Z. Molnár, D. Obura, A. Pfaff, S. Polasky, A. Purvis, J. Razzaque, B. Reyers, R. Roy Chowdhury, Y. J. Shin, I. J. Visseren-Hamakers, K. J. Willis, and C. N. Zayas (eds.). IPBES secretariat, Bonn, Germany. 56 pages.

[ii] IPCC, 2019: Summary for Policymakers. In: IPCC Special Report on the Ocean and Cryosphere in a Changing Climate [H.-O. Pörtner, D.C. Roberts, V. Masson-Delmotte, P. Zhai, M. Tignor, E. Poloczanska, K. Mintenbeck, A. Alegría, M. Nicolai, A. Okem, J. Petzold, B. Rama, N.M. Weyer (eds.)]. In press.

[iii] House Select Committee on the Climate Crisis. Solving the Climate Crisis: The Congressional Action Plan for a Clean Energy Economy and a Healthy, Resilient, and Just America. 2020.

[iv] Hoegh-Guldberg. O., et al. 2019. ‘‘The Ocean as a Solution to Climate Change: Five Opportunities for Action.’’ Report. Washington, DC: World Resources Institute. Washington, DC: World Resources Institute.

[v] Ocean Climate Action Plan – Blue New Deal; A policy framework for developing the US Blue Economy in the 21st century. Center for the Blue Economy, Middlebury Institute of International Studies at Monterey and Blue Frontier Campaign. July 2020.