Press Release

Study in Nature: Protecting the Ocean Delivers a Comprehensive Solution for Climate, Fishing and Biodiversity

A ground-breaking scientific study from 26 international experts offering the most comprehensive assessment to date of where to ramp up strict ocean protection to increase seafood security, curb biodiversity loss, and provide a cost effective solution to climate change, as well as economic benefits.

Southern Line Islands

Photograph by Southern Line Islands

Groundbreaking global study is the first to map ocean areas that, if strongly protected, would help solve climate, food and biodiversity crises

London, UK (17 March 2021)—A new study published in the prestigious peer-reviewed scientific journal Nature today offers a combined solution to several of humanity’s most pressing challenges. It is the most comprehensive assessment to date of where strict ocean protection can contribute to a more abundant supply of healthy seafood and provide a cheap, natural solution to address climate change—in addition to protecting embattled species and habitats.

An international team of 26 authors identified specific areas that, if protected, would safeguard over 80% of the habitats for endangered marine species, and increase fishing catches by more than eight million metric tons. The study is also the first to quantify the potential release of carbon dioxide into the ocean from trawling, a widespread fishing practice—and finds that trawling is pumping hundreds of millions of tons of carbon dioxide into the ocean every year, a volume of emissions similar to those of aviation.

“Ocean life has been declining worldwide because of overfishing, habitat destruction and climate change. Yet only 7% of the ocean is currently under some kind of protection,” said Dr. Enric Sala, explorer in residence at the National Geographic Society and lead author of the study, Protecting the global ocean for biodiversity, food and climate.

“In this study, we’ve pioneered a new way to identify the places that—if strongly protected—will boost food production and safeguard marine life, all while reducing carbon emissions,” Dr. Sala said. “It’s clear that humanity and the economy will benefit from a healthier ocean. And we can realize those benefits quickly if countries work together to protect at least 30% of the ocean by 2030.”

To identify the priority areas, the authors—leading marine biologists, climate experts, and economists—analyzed the world’s unprotected ocean waters based on the degree to which they are threatened by human activities that can be reduced by marine protected areas (for example, overfishing and habitat destruction). They then developed an algorithm to identify those areas where protections would deliver the greatest benefits across the three complementary goals of biodiversity protection, seafood production and climate mitigation. They mapped these locations to create a practical “blueprint” that governments can use as they implement their commitments to protect nature.

The study does not provide a single map for ocean conservation, but it offers a first-in-kind framework for countries to decide which areas to protect depending on their national priorities. However, the analysis shows that 30% is the minimum amount of ocean that the world must protect in order to provide multiple benefits to humanity.

“There is no single best solution to save marine life and obtain these other benefits. The solution depends on what society—or a given country—cares about, and our study provides a new way to integrate these preferences and find effective conservation strategies,” said Dr. Juan S. Mayorga, a report co-author and a marine data scientist with the Environmental Market Solutions Lab at UC Santa Barbara and Pristine Seas at National Geographic Society.

The study comes ahead of the 15th Conference of the Parties to the United Nations Convention on Biological Diversity, which is expected to take place in Kunming, China in 2021. The meeting will bring together representatives of 190 countries to finalize an agreement to end the world’s biodiversity crisis. The goal of protecting 30% of the planet’s land and ocean by 2030 (the “30x30” target) is expected to be a pillar of the treaty. The study follows commitments by the United States, the United Kingdom, Canada, the European Commission and others to achieve this target on national and global scales.

Safeguarding Biodiversity

The report identifies highly diverse marine areas in which species and ecosystems face the greatest threats from human activities. Establishing marine protected areas (MPAs) with strict protection in those places would safeguard more than 80% of the ranges of endangered species, up from a current coverage of less than 2%.

The authors found that the priority locations are distributed throughout the ocean, with the vast majority of them contained within the 200-mile Exclusive Economic Zones of coastal nations.

The additional protection targets are located in the high seas—those waters governed by international law. These include the Mid-Atlantic Ridge (a massive underwater mountain range), the Mascarene Plateau in the Indian Ocean, the Nazca Ridge off the west coast of South America and the Southwest Indian Ridge, between Africa and Antarctica.

"Perhaps the most impressive and encouraging result is the enormous gain we can obtain for biodiversity conservation—if we carefully chose the location of strictly protected marine areas,” said Dr. David Mouillot, a report co-author and a professor at the Université de Montpellier in France. “One notable priority for conservation is Antarctica, which currently has little protection, but is projected to host many vulnerable species in a near future due to climate change."

Shoring up the Fishing Industry

The study finds that smartly placed marine protected areas (MPAs) that ban fishing would actually boost the production of fish—at a time when supplies of wild-caught fish are dwindling and demand is rising. In doing so, the study refutes a long-held view that ocean protection harms fisheries and opens up new opportunities to revive the industry just as it is suffering from a recession due to overfishing and the impacts of global warming.

“Some argue that closing areas to fishing hurts fishing interests. But the worst enemy of successful fisheries is overfishing—not protected areas,” Dr. Sala said.

The study finds that protecting the right places could increase the catch of seafood by over 8 million metric tons relative to business as usual.

“It’s simple: When overfishing and other damaging activities cease, marine life bounces back,” said Dr. Reniel Cabral, a report co-author and assistant researcher with the Bren School of Environmental Science & Management and Marine Science Institute at UC Santa Barbara. “After protections are put in place, the diversity and abundance of marine life increase over time, with measurable recovery occurring in as little as three years. Target species and large predators come back, and entire ecosystems are restored within MPAs. With time, the ocean can heal itself and again provide services to humankind.”

Soaking up Carbon

The study is the first to calculate the climate impacts of bottom trawling, a damaging fishing method used worldwide that drags heavy nets across the ocean floor. It finds that the amount of carbon dioxide released into the ocean from this practice is larger than most countries’ annual carbon emissions, and similar to annual carbon dioxide emissions from global aviation.

“The ocean floor is the world’s largest carbon storehouse. If we’re to succeed in stopping global warming, we must leave the carbon-rich seabed undisturbed. Yet every day, we are trawling the seafloor, depleting its biodiversity and mobilizing millennia-old carbon and thus exacerbating climate change. Our findings about the climate impacts of bottom trawling will make the activities on the ocean’s seabed hard to ignore in climate plans going forward,” said Dr. Trisha Atwood of Utah State University, a co-author of the paper.

The study finds that countries with the highest potential to contribute to climate change mitigation via protection of carbon stocks are those with large national waters and large industrial bottom trawl fisheries. It calculates that eliminating 90% of the present risk of carbon disturbance due to bottom trawling would require protecting only about 4% of the ocean, mostly within national waters.

Closing a Gap

The study’s range of findings helps to close a gap in our knowledge about the impacts of ocean conservation, which to date had been understudied relative to land-based conservation.

“The ocean covers 70% of the earth—yet, until now, its importance for solving the challenges of our time has been overlooked,” said Dr. Boris Worm, a study co-author and Killam Research Professor at Dalhousie University in Halifax, Nova Scotia. “Smart ocean protection will help to provide cheap natural climate solutions, make seafood more abundant and safeguard imperiled marine species—all at the same time. The benefits are clear. If we want to solve the three most pressing challenges of our century—biodiversity loss, climate change and food shortages —we must protect our ocean.”

Additional Quotes from Supporters and Report Co-Authors

Zac Goldsmith, British Minister for Pacific and the Environment, UK

" This paper is an important contribution to the science on ocean protection and highlights the need for countries to work together to protect at least 30% of the global ocean by 2030. In the UK we are at the forefront of marine protection, and are leading the Global Ocean Alliance of more than forty nations supporting this 30 by 30 target. We will do all we can to deliver it at the UN biodiversity conference in China. "

Kristen Rechberger, Founder & CEO, Dynamic Planet

" The ocean's vast natural capital has been squandered for far too long. Our study shows that more ocean protection yields greater economic benefit and even opens up a new carbon market  to help reach climate and nature goals. As the world pushes for a net-zero economy by 2050, and needs nature restored to get there, this study comes at the perfect time and shows where to invest. "

Dr. William Chueng, Canada Research Chair and Professor, The University of British Columbia, Principal Investigator, Changing Ocean Research Unit, The University of British Columbia

" Now we have solid evidence that fully protecting over 30% of the ocean will be great for conserving fish stocks, improving fisheries production and helping to tackle climate change. The ocean will greatly benefit from an international agreement with clear ambitions for protection, similar to having the Paris Agreement to set the global warming target for climate actions. "

Dr. Jennifer McGowan, Global Science, The Nature Conservancy & Center for Biodiversity and Global Change, Yale University

" Science shows us how, political will tells us when. The ‘when’ has to be now as we simply cannot allow the ocean to fail. This research sets the foundation for the next era of ocean conservation to be one that truly places biodiversity and people at the heart of national conversations. As the world prepares to set the global agenda for the next decade of climate and biodiversity policy, this research provides the bedrock upon which decisions-makers can map and plan interactions with the ocean to deliver multiple benefits for people and biodiversity. Our research provides evidence that the time has come to retire the narrative that conservation is at odds with economic prosperity. This must be the time to build prosperous and sustainable ocean economies and this research points out how to do that. "

Dr. Alan Friedlander, Chief Scientist, Pristine Seas, National Geographic Society at the Hawai'i Institute of Marine Biology, University of Hawai'i

" By identifying where and how much of the ocean to protect, we can insure a sustainable planet well into the future. Healthy oceans are essential to our existence and this work clearly identifies where and how much to protect for the maximum benefit to people. This framework identifies how much of the ocean to protect to maximize the benefits to humanity. "

Dr. Ben Halpern, Director of the National Center for Ecological Analysis and Synthesis (NCEAS), UCSB

" Our research is a bit like building a race car. We didn't just look at how to put the best tires on the car and then install a lawnmower motor, or design an aerodynamic shell but then add wooden wheels. By looking at three different conservation objectives at once, we could find a design that produced a Formula 1 outcome for the oceans. "

Dr. Whitney Goodell, Marine Ecologist, Pristine Seas, National Geographic Society

" The ocean is critical to global biodiversity, food security, and climate change mitigation. Ocean protection can be planned in a way to maximize the multiple benefits, and coordinated global efforts to do so can be substantially more efficient than isolated national efforts. For humanity to continue benefiting from the ocean, we must think and act globally, and maximize our efforts. "

Dr. Lance Morgan, President and CEO, Marine Conservation Institute

" As the world focuses on a bold agenda to protect 30% of nature by 2030 these results provide a roadmap for conservation efforts aimed at healthier future for nature and humankind. "

Dr. Darcy Bradley, Co-Director of the Ocean and Fisheries Program at the Environmental Market Solutions Lab, UCSB

" While we consider three key benefits that marine protection is known to confer, this is really just the beginning. Our approach is a way to bring multiple stakeholders to the table, to show that their interests can be prioritized, and ultimately to demonstrate that solutions that protect large ocean areas and benefit multiple simultaneous objectives exist. "


Fact Sheet

The study, Protecting the global ocean for biodiversity, food and climate, answers the question of which places in the ocean should we protect for nature and people. The authors developed a novel framework to produce a global map of places that, if protected from fishing and other damaging activities, will produce multiple benefits to people: safeguarding marine life, boosting seafood production and reducing carbon emissions. Twenty-six scientists and economists contributed to the study.

Study’s Topline Facts

  • Ocean life has been declining worldwide because of overfishing, habitat destruction and climate change. Yet only 7% of the ocean is currently under some kind of protection.
  • A smart plan of ocean protection will contribute to more abundant seafood and provide a cheap, natural solution to help solve climate change, alongside economic benefits.
  • Humanity and the economy would benefit from a healthier ocean. Quicker benefits occur when countries work together to protect at least 30% of the ocean.
  • Substantial increases in ocean protection could achieve triple benefits, not only protecting biodiversity, but also boosting fisheries’ productivity and securing marine carbon stocks.

Study’s Topline Findings

  • The study is the first to calculate that the practice of bottom trawling the ocean floor is responsible for one gigaton of carbon emissions on average annually. This is equivalent to all emissions from aviation worldwide. It is, furthermore, greater than the annual emissions of all countries except China, the U.S., India, Russia and Japan.
  • The study reveals that protecting strategic ocean areas could produce an additional 8 million tons of seafood.
  • The study reveals that protecting more of the ocean--as long as the protected areas are strategically located--would reap significant benefits for climate, food and biodiversity.

Priority Areas for Triple Wins

  • Priority conservation areas change depending on the priority that is valued most--biodiversity, climate change or food provision. 
    • If society were to value marine biodiversity and food provisioning equally, and established marine protected areas based on these two priorities, the best conservation strategy would protect 45% of the ocean, delivering 71% of the possible biodiversity benefits, 92% of the food provisioning benefits and 29% of the carbon benefits.
    • If no value were assigned to biodiversity, protecting 29% of the ocean would secure 8.3 million tons of extra seafood and 27% of carbon benefits. It would also still secure 35% of biodiversity benefits.
  • Global--and not national--priorities should be the focus. 
    • Global-scale prioritization helps focus attention and resources on places that yield the largest possible benefits.
    • A globally coordinated expansion of marine protected areas (MPAs) could achieve 90% of the maximum possible biodiversity benefit with less than half as much area as a protection strategy based solely on national priorities.
  • Exclusive Economic Zones (EEZs) are key. 
    • Among those unprotected marine areas with the highest potential for a triple win--biodiversity conservation, carbon storage and food provision--most are found in EEZs. 
      • EEZs are areas of the global ocean within 200 nautical miles off the coast of maritime countries that claim sole rights to the resources found within them. (Source)

Priority Areas for Climate

  • Eliminating 90% of the present risk of carbon disturbance due to bottom trawling would require protecting 3.6% of the ocean, mostly within EEZs.
  • Priority areas for carbon are where important carbon stocks coincide with high anthropogenic threats, including Europe’s Atlantic coastal areas and productive upwelling areas.

Countries with the highest potential to contribute to climate change mitigation via protection of carbon stocks are those with large EEZs and large industrial bottom trawl fisheries.

Priority Areas for Biodiversity

  • Through protection of specific areas, the average protection of endangered species could be increased from 1.5% to 82% and critically endangered species from 1.1% to and 87%.
  • Other priority areas are around seamount clusters, offshore plateaus and biogeographically unique areas including: 
    • the Antarctic Peninsula
    • the Mid-Atlantic Ridge
    • the Mascarene Plateau
    • the Nazca Ridge
    • the Southwest Indian Ridge
  • Despite climate change, about 80% of today’s priority areas for biodiversity will still be essential in 2050. In the future, however, some cooler waters will be more important protection priorities, whereas warmer waters will likely be too stressed by climate change to shelter as much biodiversity as they currently do. Specifically, some temperate regions and parts of the Arctic would rank as higher priorities for biodiversity conservation by 2050, whereas large areas in the high seas between the tropics and areas in the Southern Hemisphere would decrease in priority.

Priority Areas for Food Provision

  • If we only cared about increasing the supply of seafood, strategically placed MPAs covering 28% of the ocean could increase food provisioning by 8.3 million metric tons.


The Campaign for Nature works with scientists, Indigenous Peoples, and a growing coalition of over 100 conservation organizations around the world who are calling on policymakers to commit to clear and ambitious targets to be agreed upon at the 15th Conference of the Parties to the Convention on Biological Diversity in Kunming, China in 2021 to protect at least 30% of the planet by 2030 and working with Indigenous leaders to ensure full respect for Indigenous rights.

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