Climate MattersJune 7, 2023

World Oceans Day


  • World Oceans Day is June 8. Oceans play a key role in livelihoods, food supplies, and climate. 

  • Oceans remove roughly 26% of the CO2 from burning fossil fuels and store it in marine life, seawaters, and on the seafloor—as described in Climate Central’s new report, Ocean Carbon

  • But human-caused warming and continued carbon pollution put tremendous pressure on marine ecosystems and processes that remove and hold carbon long term.

  • Restoring and protecting oceans can be a climate solution, but must be paired with deep and rapid cuts to carbon pollution.

CM: World Oceans Days 2023 (EN)
Click the downloadable graphic: World Oceans Day

World Oceans Day, on June 8, is a time to recognize how the ocean supports humans and protects our warming planet.

Oceans cover roughly 70% of the planet and affect everyone on Earth, regardless of how far we live from the coast. Oceans influence global climate, support the livelihoods of millions of people around the world, and provide food and nutrition for billions.

Oceans also absorb around 90% of the extra heat caused by carbon pollution and remove about 26% of the CO2 released by humans each year from burning fossil fuels.

Carbon storage in the ocean

Oceans store around 45 times more carbon than the atmosphere and 12 times more than ecosystems on land—making oceans the planet’s largest source of carbon storage, capable of capturing and holding billions of tons of carbon for long periods of time.

How long carbon is stored in the ocean depends primarily on how deep it sinks. Carbon can be stored short-term (months or years) in shallower waters, but carbon transported to deep ocean waters can potentially stay out of the atmosphere for centuries. If carbon sinks even deeper to the seafloor, it could be locked into sediments for millennia.

CM: World Oceans Day 2023 (EN) 2
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Ocean carbon: from the surface to the seafloor

Climate Central’s new report Ocean Carbon provides a more detailed overview of the ocean carbon cycle and how ocean carbon is stored in both living and nonliving parts of coastal and marine ecosystems, including:

  • Coastal habitats
    Healthy, intact coastal ecosystems—including mangroves, seagrass meadows, and saltmarshes—have tremendous potential for carbon storage in soils, sediment, and plant biomass.

  • Marine waters—shallow to deep
    The vast majority of ocean carbon is stored in the water as a dissolved gas.

  • Marine life—from microscopic to megafauna
    Near the sea surface, tiny plant-like organisms called phytoplankton convert CO2 into organic carbon (carbon that is incorporated into life forms) during photosynthesis.

    Phytoplankton are the base of a vast marine food web. The zooplankton, small fish, and other sea life that feed on phytoplankton are consumed by bigger predatory fish and whales. This organic carbon is stored in the biomass of marine life along the food chain.

    Whales are unique links in the ocean carbon cycle because they move nutrients vast distances and contain huge amounts of carbon in their bodies over a lifespan of many decades.

In addition to being stored in living marine organisms, carbon in the ocean can take another pathway: it can sink. From decaying microscopic phytoplankton cells to the carcasses of large whales, carbon is transferred to the deep ocean when biomass sinks.

  • Marine sediments and the seafloor
    Carbon that makes its way to depths of the ocean can potentially be locked away for millennia. Over millions of years, deposits on the seafloor are compressed into rock formations for carbon storage on geologic timescales. 

Oceans at risk on a warming planet

As humans pump more carbon pollution into the atmosphere, primarily through burning fossil fuels, we disrupt the planet’s carbon cycle—of which the oceans are an important part. 

Record levels of atmospheric CO2 mean that more CO2 is absorbed into the ocean, causing ocean acidification—a fundamental change in seawater chemistry that affects marine life. Warming ocean temperatures driven by climate change are a growing threat to fisheries on both coasts.

The warmest year on record for oceans was 2022, and ocean temperatures continue to break records in 2023. April 2023 experienced the second-highest recorded global ocean temperatures, and the highest for any April on record.

Oceans face other pressures from human activity that impact their health, biodiversity, and ability to store and sequester carbon, including: unsustainable fishing and harvesting practices; unchecked coastal development; and marine pollution.

CM: Regional Ocean Warming, Northeast Atlantic
Regional Ocean Warming, Northeast Atlantic
CM: Ocean Heatwaves, Global Marine Heatwave Days 1900-2016
Ocean Heatwaves, Global Marine Heatwave Days 1900-2016

Protecting and restoring ocean ecosystems

Reducing pressures from human-caused warming and other activities can help marine ecosystems weather some of the effects of climate change—up to a point.

When paired with deep cuts to emissions, the conservation and restoration of ocean ecosystems can bolster the ocean’s carbon storage capacity.

There are many ways that humans can restore, protect, and better manage blue carbon—a term for carbon captured by coastal and marine ecosystems. These solutions can range from sustainable management of fisheries and restoration of whale populations, to conservation of coastal and marine habitats. 

Emerging approaches to enhance ocean CO2 removal

There are also emerging approaches that aim to enhance the ocean’s capacity to remove CO2. Often categorized as geoengineering, these approaches may hold promise, but research into most is nascent. 

Climate Central’s report Ocean Carbon briefly describes a few of these approaches. More detailed information about ocean-based CO2 removal research and technology can be found in a 2022 report from the National Academies of Sciences, Engineering, and Medicine: A Research Strategy for Ocean-based Carbon Dioxide Removal and Sequestration.


Journalists can apply to join the Pulitzer Center’s Ocean Reporting Network (deadline: June 18) to report on threats to ocean resources, biodiversity, and coastal communities.

Find region-specific ocean, coastal, or Great Lakes data.

The Integrated Ocean Observing System (IOOS) is NOAA’s national-regional partnership that collects high-quality data relevant to the nation’s ocean, coastal, and Great Lakes regions. IOOS operates across 11 U.S. regional associations. Each regional association’s website is a hub for region-specific data. 

Find climate change adaptation projects in U.S. coastal and marine regions.

NOAA’s National Marine Protected Areas Center enables marine habitat conservation and restoration—important nature-based solutions for our changing oceans. NOAA’s interactive Restoration Atlas can be used to find coastal and marine habitat restoration projects throughout the U.S. The EPA’s Coastal Adaptation Toolkit provides resources on coastal change, impacts, and adaptation options. The EPA’s Climate Ready Estuaries site tracks adaptation projects in coastal U.S. states. 

Locate marine protected areas off the coast of your state.

Marine protected areas (MPAs) are defined marine areas in which certain activities, such as fishing or fossil fuel extraction, are limited or banned to preserve ecosystems. MPAs often include important coastal habitats, such as mangroves or salt marshes. Use the interactive map feature of NOAA’s Marine Protected Area Inventory to identify protected coastal areas near your state. Learn more about definitions, classification, and levels of protection in MPAs.

Find out more about blue carbon project potential by state.

Data requirements (and availability) for implementing blue carbon projects vary by state. In the Blue Carbon Inventory (2021), the Pew Charitable Trusts assessed blue carbon ecosystem data in select coastal states, including California, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Virginia, and Washington. The report relies on data from the Coastal Carbon Atlas, a resource curated by the Coastal Carbon Research Coordination Network at the Smithsonian Environmental Research Center.

Livelihoods that depend on specific species (e.g., scallop harvesting) are vulnerable to climate change impacts. Learn more about regional livelihood-supporting species.

NOAA Fisheries’ Species Directory, searchable by U.S. region, provides facts about each species' biology, range, fishery management, and harvest. NOAA FishWatch includes resources on sustainable fisheries management, as well as a sustainable seafood database that is searchable by U.S. region.


Enrique Curchitser, PhD
Rutgers University
Relevant expertise: oceans and climate

Rod Fujita, PhD
Oceans Program, Director of Research and Development
Environmental Defense Fund
Relevant expertise: climate change and fisheries
Media contact: Tad Segal,

Grace Saba, PhD
Associate Professor
Rutgers University
Relevant expertise: climate change, marine ecology, ocean nutrient cycling and carbon sequestration

Julie Pullen, PhD
Partner & Chief Scientist
Relevant expertise: ocean climate technology solutions

Cymie Payne, Esq.
Associate Professor
Rutgers University
Relevant expertise: global governance of ocean resources


Submit a request to SciLine from the American Association for the Advancement of Science or to the Climate Data Concierge from Columbia University. These free services rapidly connect journalists to relevant scientific experts. 

Browse maps of climate experts and services at regional NOAA, USDA, and Department of the Interior offices.  

Explore databases such as 500 Women Scientists, BIPOC Climate and Energy Justice PhDs, and Diverse Sources to find and amplify diverse expert voices. 

Reach out to your State Climate Office or the nearest Land-Grant University to connect with scientists, educators, and extension staff in your local area.

Browse the Women4Oceans global map of female ocean professionals.