Pacific Islands Coral Reef Project - National Park Service

Pacific Islands Coral Reef Program

Ocean Acidification Dooms Ocean Coral Reefs

Fishes
Nat'l Park
of Am Samoa

Corals
Nat'l Park
of Am Samoa

Marine Invertebrates,
Nat'l Park
of Am Samoa

Birds
Nat'l Park
of Am Samoa

University of Hawaii -
National Park Service

"Higher water temperatures and ocean acidification due to increasing atmospheric carbon dioxide will present major additional stresses to coral reefs, resulting in significant dieoffs and limited recovery.

In addition to carbon dioxide's heat-trapping effect, the increase in its concentration in the atmosphere is gradually acidifying the ocean. About one-third of the carbon dioxide emitted by human activities has been absorbed by the ocean, resulting in a decrease in the ocean's pH. Since the beginning of the industrial era, ocean pH has declined demonstrably and is projected to decline much more by 2100 if current emissions trends continue. Further declines in pH are very likely to continue to affect the ability of living things to create and maintain shells or skeletons of calcium carbonate. This is because at a lower pH less of the dissolved carbon is available as carbonate ions. Ocean acidification will affect living things including important plankton species in the open ocean, mollusks and other shellfish, and corals. The effects on reef-building corals are likely to be particularly severe during this century. Coral calcification rates are likely to decline by more than 30 percent under a doubling of atmospheric carbon dioxide concentrations, with erosion outpacing reef formation at even lower concentrations."

"Calcium Carbonate Saturation in Ocean Surface Waters"

The following are a series of direct quotes pertaining to coral reefs from the 2009 Report to Congress, Global Climate Change Impacts in the United States:

This is a doomsday outlook for our oceans. It is time for us to act.

Download the entire report Global Climate Change Impacts in the United States (13.09 mb pdf).

Corals that form the reefs in the Florida Keys, Puerto Rico, Hawaii, and the Pacific Islands are projected to be lost if carbon dioxide concentrations continue to rise at their current rate." (emphasis added) pgs 151-152.

Corals require the right combination of temperature, light, and the presence of calcium carbonate (which they use to build their skeletons). As atmospheric carbon dioxide levels rise, some of the excess carbon dioxide dissolves into ocean water, reducing its calcium carbonate saturation. As the maps indicate, calcium carbonate saturation has already been reduced considerably from its pre-industrial level, and model projections suggest much greater reductions in the future. The blue dots indicate current coral reefs. Note that under projections for the future, it is very unlikely that calcium carbonate saturation levels will be adequate to support coral reefs in any U.S. waters.