Climate Change and Ocean Acidification
Greater Farallones

mesophotic reefs
Intertidal monitoring tracks shifts in ranges, like this Anthopleura sola anemone. It’s range may be shifting northward due to climate change. Credit: GFNMS

Why is it a concern?

On global and regional scales, the ocean is changing due to increasing atmospheric carbon dioxide (CO2) and associated global climate change. Regional physical changes in the North-central California coast and ocean include sea level rise, coastal erosion and flooding, and changes in precipitation and land runoff, ocean-atmosphere circulation, and ocean water properties. These changes in turn lead to biotic responses within ocean ecosystems, including changes in physiology, phenology, and population connectivity, as well as species range shifts.

The Greater Farallones NMS and Cordell Bank NMS worked with partners to identify and synthesize potential climate change impacts to habitats and biological communities along the north-central California coast. Key Issues identified include:

  • Observed increase in sea level (100 year record at mouth of San Francisco Bay)
  • Expected increase in coastal erosion associated with changes in sea level and storm waves
  • Observed decrease in spring runoff of freshwater through San Francisco Bay (decreased Sierra snowpack)
  • Observed increase in precipitation variability (drier dry years, wetter wet years)
  • Observed increase in surface ocean temperature offshore of the continental shelf (50 year record)
  • Observed increase in winds driving coastal upwelling of nutrient-rich waters and associated observed decrease in surface ocean temperature over the continental shelf (30 year record), leading to increased acidification
  • Observed increase in extreme weather events (winds, waves, storms resulting in erosion, flooding and increased runoff and siltation)
  • Expected decrease in seawater pH, due to uptake of CO2 by the ocean
  • Observed northward shift of key species (including Humboldt squid, volcano barnacle, blue whales, bottlenose dolphins, etc.)
  • Possible shift in dominant phytoplankton (from diatom to dinoflagellate blooms)

In addition, ocean acidification poses a serious threat to the health of the oceans habitats within the sanctuary. As concentrations of CO2 increase in the ocean, and ocean chemistry changes, organisms with calcium carbonate shells and other structures may be impacted by slower growth rates and decreased fitness. The consequences of a reduction in shell-forming animals and algae can ultimately lead to shifts in ecosystem structure and dynamics, altering marine food webs. Locally, affected intertidal species include barnacles and mussels, and calcium carbonate-forming algae. A decline in these organisms will cause declines in seabirds, shorebirds, and marine mammals that forage on these species, as well as disrupt sport and commercial harvests.  Warming of sea surface temperatures and increased depth of the warmer surface waters can create favorable conditions for increased establishment of invasive species and create conditions, which are more favorable to pathogens in marine invertebrates.

Overview of Research

Research conducted by Sanctuary scientists and partners provides critical information to address existing and emerging resource conservation and management issues. The Overview of Research highlights some, but not necessarily all, of the research activities completed or ongoing at the Sanctuary.

Project Name PI and contacts Links

Downscaling climate change models to local site conditions: Effects of sea level rise and extreme events to California coastal habitats

John Takekawa

Utilizing geochemistry and microfossils and corals to better understand climate change, OA and resiliency

Tessa Hill
and Kate Davis

Applied California Current Ecosystem Studies

Jan Roletto, Jaimie Jahnke, and Dani Lipski


Pete Raimondi and Mark Carr

Beach Watch

Jan Roletto and Kirsten Lindquist  and


Science Needs and Questions

The best available science is used by Sanctuary scientists and managers working to address priority resource conservation and management issues. As priorities change and new issues emerge, each Sanctuary develops new science needs and questions and works with partners to address them.

  • What habitats are most at risk from changing climate? How can this information be used to effectively plan restoration projects?
  • Which species will be most affected by various climate change drivers?  How can the sanctuary ease other impacts to these species?
  • How will ocean acidification impact the Sanctuary and directly affect various species, including deep-water corals, larval fish and crustaceans, krill and other calcifying invertebrates?
  • How will changes in upwelling intensity and timing impact krill populations and larval dispersal and recruitment of rockfishes and invertebrates?
  • How will changes in upwelling intensity and timing change the "ocean forcing" effect in sanctuary estuaries?

Education and Outreach Material

The West Coast Region Educational website for educators on Ocean Acidification includes background information, videos, curriculum and other teaching materials.

Greater Farallones NMS programs:

  • Annual Teacher Workshop on climate change and ocean acidification – includes components on current research, hands-on activities and additional teacher resources
  • Pass the Plankton Please – a 4th grade field trip that includes an ocean acidification component
  • At Your School – Sea of Change – a program for 6th-12th graders with a hands-on component related to ocean acidification
  • Sanctuary Explorers' Camp – an annual camp that includes an ocean acidification component
  • Oceans After School Program – an after-school program geared for grades 3rd – 5th that includes an ocean acidification component


Duncan, B.E., K.D. Higgason, T.H. Suchanek, J. Largier, J. Stachowicz, S. Allen, S. Bograd, R.
Breen, H. Gellerman, T. Hill, J. Jahncke, R. Johnson, S. Lonhart, S. Morgan, J. Roletto, F.
Wilkerson. 2013. Ocean Climate Indicators: A Monitoring Inventory and Plan for Tracking
Climate Change in the North-central California Coast and Ocean Region. Report of a Working
Group of the Gulf of the Farallones National Marine Sanctuary Advisory Council. 74pp.

Largier, J.L., B.S. Cheng, and K.D. Higgason, editors. 2010. Climate Change Impacts: Gulf of the Farallones and Cordell Bank National Marine Sanctuaries. Report of a Joint Working Group of the Gulf of the Farallones and Cordell Bank National Marine Sanctuaries Advisory Councils. 121pp.