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Resource Issues: Climate Change

Overview of the issue

ocean front home being hit by wave
Oceanfront homes in Aptos Seascape suffered major damage in January 1983. Photo Dr. Gary Griggs/UCSC

Climate change's effects on the marine environment, including warming seawater temperatures, ocean acidification, sea level rise, and changes in currents, upwelling and weather patterns, have the potential to cause fundamental changes in the nature and character of marine and coastal ecosystems.

The waters of Monterey Bay National Marine Sanctuary, as well as surrounding coastal areas and communities, are experiencing the effects of climate change (e.g., sea level change, increasing sea surface temperature, and ocean acidification).

Through regional collaboration and coordination, the Monterey Bay coastal community is preparing for the impacts of climate change in a time of limited funding and resources, and ever increasing greenhouse gas emissions. 

How is the Sanctuary involved?

Progress Towards Preparing for the Future: Climate Change and the Monterey Bay Shoreline is a series of forums hosted by Center for Ocean Solutions, MBNMS and partners to bring together state and local government planning staff to learn about and share information on preparing for sea level rise and coastal hazard issues along the Monterey Bay coastline. To date, two workshops have been held in Monterey, and planning is underway for a third public engagement workshop.

Ocean Acidification

As we burn fossil fuels from cars and factories on land, CO2 is released into the atmosphere and the ocean absorbs about one third. This CO2 then reacts with seawater to form carbonic acid and releases H ions, which lowers pH and makes the ocean more acidic. The H ions pull away carbonate ions to form bicarbonate, making carbonate ions less available to organisms to form CaCO3 shells and hard parts, as illustrated in the diagram below.

ocean acidification diagram

Approximately 55M years ago, an ocean acidification event occurred - Paleocene-Eocene Thermal Maximum (PETM). The strongest evidence for this is that much of the calcium carbonate in the deep sea disappeared. The changes in the physical environment also included significant warming, and a decrease in oxygen in the ocean. The changes in the biology include evidence for plankton blooms, some extinctions, a high turnover in species, and changes in calcification.

In 2009, thirteen ONMS sanctuary advisory council's passed resolutions on ocean acidification, and in 2011, the West Coast Regional Office of NOAA's Office of National Marine Sanctuaries created a Task Force to take action on the resolutions.

Input from the Councils was incorporated into a west coast ocean acidification action plan , which includes seven strategies: (1) Monitoring for Ocean Acidification; (2) Research on Ocean Acidification; (3) Education and Outreach; (4) Mitigating Damages to Sanctuary Resources; (5) Influencing Regional and National Policy; (6) Demonstrate Leadership by Reducing Carbon Emissions; and (7) Internal Coordination on Ocean Acidification Issues.

Sea Level Rise

shorebirds on the beachGlobally, sea level rise is driven by two primary factors—global ice melt and thermal expansion of seawater, but locally there are numerous processes that can alter the rate, extent, and duration of changes in sea level. As such, accurately predicting sea level over the coming centuries for specific locations is very challenging. Currently, the state of California is using estimates of global sea level rise produced by Ramstorf 2007 and Cayan et al. 2008 for coastal adaptation planning purposes under Executive Order S‐13‐08. These projections suggest possible sea level rise of approximately 14 inches (36 cm) by 2050 and a high value of approximately 55 inches (140 cm) by 2100. However, recent evidence suggests these values may prove to be underestimates of the possible rise in global sea level.

Coastal Erosion

Threats from climate change and sea level rise to coastal structures and communities from coastal erosion, as well as the environmental impacts associated with coastal armoring, have been of growing concern to many. A recent study found that erosion rates along the southern Monterey Bay shoreline between Moss Landing and Wharf II in Monterey are the highest in the State of California. Although this shoreline is not heavily developed, eight oceanfront facilities are at a high risk from erosion over the next fifty years. A recent sanctuary-led study, Evaluation of Erosion Mitigation Alternatives for Southern Monterey Bay, developed a number of recommendations for future mitigation measures in this region.

Coastal Inundation, storm and wave damage

Coastal inundation occurs when normally dry land becomes covered by water and it is one of the most costly and damaging impacts associated with sea level rise. Areas that will be affected include critical habitat areas such as Elkhorn Slough and other low-lying coastal areas such agricultural properties, and private coastal residences. Seasonal patterns of storms and wave intensity are the primary driving forces behind coastal erosion along the California coast. More information can be found in this report.


  • Climate Change Impacts: Monterey Bay National Marine Sanctuary (6M PDF)
    The impacts of climate change are intensifying both globally and locally, threatening America’s physical, social, economic, and environmental well-being. National marine sanctuaries and monuments must contend with rising water temperatures and sea levels, water that is more acidic and contains less oxygen, shifting species, and altered weather patterns and storms. While all of our sanctuaries and monuments must face these global effects of climate change, each is affected differently. This report explores how Monterey Bay National Marine Sanctuary is being, and is projected to be, affected by climate change.
  • 2014 Monterey Bay Sea Level Rise Vulnerability Assessment (6M PDF)
    Prepared for Monterey Bay Sanctuary Foundation (June 2014). This report presents technical documentation of the methods used to map erosion and coastal flood hazards under various future climate scenarios for the Monterey Bay, California coastline.
  • Evaluation of Erosion Mitigation Alternatives for Southern Monterey Bay
    ESA PWA (May 2012) Prepared for Monterey Bay Sanctuary Foundation and the Southern Monterey Bay Coastal Erosion Working Group, 30 May 2012, ESA PWA REF.#1972.00. 216pp. While focused on southern Monterey Bay, this report will help clarify the benefits, costs and effectiveness of a range of erosion mitigation management measures for the entire California shoreline.
  • Preparing for the Future: Climate Change and the Monterey Bay Shoreline
    Abeles, A., K. Grimmer, and H. Papendick (December 2011) Summary Report for Participants, December 6, 2011, Monterey, CA. This report describes a day-long workshop that initiated a region-wide discussion and collaboration on climate change adaptation in Monterey Bay.
  • National Marine Sanctuaries of the West Coast Ocean Acidification Action Plan
    Lott, D., E. Bowlby, D. Howard, K. Higgason, K. Grimmer, L. Francis, L. Krop, R. Feely, and L. Jewett (August 2011). This report outlines 7 strategies that will better prepare sanctuaries in addressing ocean acidification issues.

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Reviewed: April 11, 2024
Web Site Owner: National Ocean Service

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