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Climate change and the ocean

Deep-sea coral communities don’t receive as much attention as their shallow-water counterparts, but their roles in marine ecosystems are equally as important. MBARI researchers are studying how vulnerable communities, like bubblegum corals (Paragorgia arborea), are affected by human activities. Image: © 2019 MBARI

Climate change and the ocean

Climate change has serious, long-term, and far-reaching negative consequences for our ocean.

Burning fossil fuels, raising livestock, and clearing forests are just three examples of human activities that release billions of tons of CO2 and other heat-trapping gases into our atmosphere every year, making our planet warmer. The ocean has buffered us from the worst impacts of climate change—absorbing more than 25 percent of the excess CO2 and more than 90 percent of the excess heat. But these climate services come at a significant cost for marine ecosystems and result in harmful impacts including:

  • Increasing ocean temperature: bleaches coral reefs, shifts where fish can live, and decreases ocean wildlife,
  • Ocean acidification: causes a depletion of carbonate ions, which are critical for shell-forming animals like oysters, crabs, and shrimp,
  • Decreasing oxygen: creates areas that suffocate marine animals, shrinks their habitats, and forces them to swim into places where they are more vulnerable to predators,
  • More intense tropical storms and higher sea level: puts coastal communities in harm’s way and destroys coastal wetland habitats which include mangroves and salt marshes.

These and other negative impacts are documented and summarized in the Intergovernmental Panel on Climate Change (IPCC) Special Report on the Ocean and Cryosphere in a Changing Climatereleased on September 25, 2019, in Monaco. It is the first IPCC report to focus specifically on the marine realm.

In order to protect the ocean and slow the impacts of climate change, the science indicates we need to take action on two fronts:

  • Cut net carbon dioxide emissions to zero by 2050;
  • Increase ocean health—by reducing pollution, overfishing and safeguarding critical marine and coastal habitats.

Climate change: A triple threat for the ocean

September 25, 2019 – A just-released scientific report connects a host of ocean changes with human activities that take place largely on land.

MBARI climate change research

MBARI’s technical achievements and knowledge are transforming climate change research with novel methods and technologies. Several MBARI research projects have tackled issues related to climate change, seeking to understand how marine life responds to a changing ocean.

Additional MBARI climate change research:

Climate change research from MBARI partners:

“Environmental conditions throughout the world ocean are changing in response to fossil fuel emissions and greenhouse warming in the atmosphere.”

—Scientist Jim Barry

Climate and the ocean facts

From the Intergovernmental Panel on Climate Change report, The Ocean and Cryosphere in a Changing Climate:

  • Carbon dioxide uptake: It is very likely that the ocean has taken up between 20 to 30 percent of total anthropogenic carbon since the 1980s.
  • Loss of oxygen: The open ocean is losing oxygen overall with a very likely loss of 0.5 to 3.3 percent between 1970 and 2010 from the surface to depths of 1,000 meters. The oxygen minimum zones are likely expanding by 3 to 8 percent, most notably in tropical areas.
  • Heat: The ocean has taken up more than 90 percent of the excess heat in the climate system since 1970. The rate of ocean warming has more than doubled since 1993.
  • Coastal wetlands: Nearly 50 percent of coastal wetlands have been lost over the 20th century since pre-industrial time, as a result of the combined effect of localized human pressures, sea level rise, warming and extreme climactic events.
  • Fisheries: In many regions, declines in the abundance of fish and shellfish stocks due to direct and indirect effects of global warming have already reduced fisheries catches.
  • Harmful algal blooms: Harmful algal blooms show range expansion and increased frequency in coastal areas since the 1980s in response to both climatic and non-climatic drivers. The observed trends are attributed partly to the effects of ocean warming, acidification, and loss oxygen as well as eutrophication and pollution.

Climate change in Monterey Bay

  • Temperature: The surface of Monterey Bay has warmed about 0.8°C (1.4°F) since 1930.
  • Acidity: 10 percent increase in acidity near the surface over the last 20 years.
  • Oxygen: The minimum oxygen zone is getting bigger.

MBARI Publications

Lesson plans

The following lesson plans about the ocean and climate change were created by teachers participating in the EARTH teacher workshops. EARTH—which stands for Education and Research: Testing Hypotheses—uses near-real-time data from ocean observatories to create lessons for students.


Climate change:

Specific subjects:

Science publications: