Coastal and Marine

The key stressors to Oregon’s coastal ocean will be the result of ocean warming, altered currents, and acidification. In addition, sea level rise could adversely affect Oregon’s coastal communities and ecosystems.

Ocean Warming

Ocean warming may have multiple, interacting effects on species geographic distribution and ecological community structure. Rising ocean temperatures have been implicated in changing the geographic range of both fish and plankton (Perry et al 2005, Batten and Welch 2004). A case in point is that of the Humboldt squid. Recently, the squid has extended it’s range northward. This range expansion coincides with climate related changes in the marine ecosystem, as well as with a reduction in competing top predators. Unravelling interactive effects such as these is an issue of growing concern (Zeidberg and Robinson 2007).

The stability of deepwater methane-hydrate ice under conditions of climate change is unknown. If deepwater deposits of methane-hydrate ice were to melt as a result of oceanic warming, a strong positive carbon-climate feedback could result (Schiemeier 2008, Krey et al 2009).

Alteration of Ocean Currents

The effects of climate change on ocean currents is still uncertain (Toggweiler and Russell 2008, Bryden et al 2005). However, any changes in oceanic circulation may affect patterns of upwelling, larval dispersal, and dead zones at multiple spatial and temporal scales (linked to ENSO, PDO, etc.).

Ocean Acidification

Ocean acidification refers to the process whereby the pH of the ocean is reduced as a result of the uptake of anthropogenically generated carbon dioxide from the atmosphere  (Caldiera and Wickett 2003). Acidification will adversely affect organisms with calcified external structures, including coccolithophores, pteropods, coralline algae, and various macroinvertebrates (Orr et al 2005).

Sea Level Rise

The IPCC Fourth Assessment report projects a sea-level rise of between 0.18 and 0.59 meters (7 to 23 inches) (IPCC 2007). This projection, however, does not incorporate the melting of the West Antarctic Ice Sheet (an event that some scientists feel is possible given current trends). If the West Antarctic Ice Sheet were to melt, coastal areas of North America (including the Oregon coast), could experience sea level rises of more than 5 meters (16 feet) (IPCC 2007, Mitrovica et al 2009).

A rise in sea level could threaten many of Oregon’s coastal areas. Impacts could include the inundation of coastal estuaries, and erosion of beaches, and sandy bluffs. In addition, coastal towns could experience infrastructure damage in the form of flooding and damage to water and sewer systems.

A study by the National Wildlife Federation, using a projected sea level rise of 27.3 inches by 2100, predicts the following impacts to coastal areas of the Pacific Northwest (National Wildlife Federation 2007):

  • Estuarine beaches will undergo inundation and erosion to the tune of a 65 percent loss. 
  • As much as 44 percent of tidal flat will disappear. 
  • 13 percent of inland fresh marsh and 25 percent of tidal fresh marsh will be lost.
  • 11 percent of inland swamp will be inundated with salt water, while 61 percent of tidal swamp will be lost.
  • 52 percent of brackish marsh will convert to tidal flats, transitional marsh and saltmarsh.
  • 2 percent of undeveloped land will be inundated or eroded to other categories across all study areas. 


Batten, S. and Welch, D., 2004, Changes in oceanic zooplankton populations in the North-east Pacific associated with the possible climatic regime shift of 1998/1999. Deep Sea Research II, 51, 863-873.

Bryden, H., Longworth, H., and Cunningham, S., 2005, Slowing of the Atlantic meridional overturning circulation at 25° N, Nature, 438, 655-657.

Caldeira, K., Wickett, M., 2003, Anthropogenic Carbon and Ocean PH, Nature, 425, 365–365.

Krey V., Canadell, J., Nakicenovic, N., Abe, Y., Andruleit, H., Archer, D., Grubler, A., Hamilton, N., Johnson, A., Kostov, V., Lamarque, J., Langhorne, N., Nisbet, E., O’Neill, B., Riahi, K., Riedel, M., Wang, W., and Yakushev, V., 2009, Gas hydrates: entrance to a methane age or climate threat?, Environ. Res. Lett., 4.

Mitrovica, J, Gomez, N, Clark, P., 2009, The Sea-Level Fingerprint of West Antarctic Collapse, Science, 323, 753.

National Wildlife Federation, 2007, Sea-level Rise and Coastal Habitats in the Pacific Northwest: An Analysis for Puget Sound, Southwestern Washington, and Northwestern Oregon, July 2007.

Orr, J., Fabry, V., Aumont, O., Bopp, L., Doney, S., Feely, R., Gnanadesikan, A., Gruber N., Ishida, A., Joos, F., Key, R., Lindsay, K., Maier-Reimer, E., Matear, R., Monfray, P., Mouchet, A., Najjar, R., Plattner, G., Rodgers, K., Sabine, C., Sarmiento, J., Schlitzer, R., Slater, R., Totterdell, I., Weirig, M., Yamanaka, Y., Yool, A., 2005, Anthropogenic ocean acidification over the twenty-first century and its impact on calcifying organisms, Nature, 437, 681-686.

Perry, A., Low, P., Ellis, J., Reynolds, J., 2005, Climate Change and Distribution Shifts in Marine Fishes, Science, 308, 1912-1915.

Scheimeier, Q., 2008, Fears surface over methane leaks, Nature, 455, 572-573.
Toggweiler, J., and Russell, J., 2008, Ocean Circulation in a warming climate, Nature, 451, 286-288.

Zeidberg, L. and Robison, B, 2007, Invasive range expansion by the Humboldt squid,
Dosidicus gigas, in the eastern North Pacific, Proceedings of the National Academy of Sciences, 104(31), 12948-12950.