Two scientific studies published in 2005 signal that the oceans are getting more acidic and that marine organisms' ability to survive will be compromised.

• "Ocean Acidification Due to Increasing Atmospheric Carbon Dioxide." The Royal Society. 30 June 2005 (Ref 12/05). PDF available at www.royalsoc.ac.uk/displaypagedoc.asp?id=13539

• Orr, James C. et al. "Anthropogenic Ocean Acidification Over the Twenty-First Century and Its Impact on Calcifying Organisms." Nature 437: 681-686. 29 September 2005 at www.nature.com; Parks, Noreen. "Ocean Acidification Bad for Shells and Reefs." Science. 28 September 2005 at sciencenow.sciencemag.org

The Royal Society paper establishes that oceans are absorbing carbon dioxide from the atmosphere, resulting in ocean acidification. The study states that, in the last two centuries, oceans have absorbed roughly half of the amount of CO2 emitted by fossil fuel use and cement production. This assimilation of carbon dioxide has caused ocean pH to be reduced as hydrogen ion concentrations increase.

Orr et al. conclude that higher ocean acidity will be devastating to the marine environment within a short period of time -- within tens of years instead of hundreds of years. Basing analyses on 13 global carbon models assuming "business-as-usual" trends in greenhouse gas emissions, their conclusions are that the oceans will be undersaturated in calcium carbonate: leading to increasing difficulty for shelled organisms to create skeletons and shells. By 2050, with increasing CO2 concentrations and increased acidity, the problem will be severe in the polar waters of the Southern Ocean. By 2100, all of the Southern Ocean and the sub-Arctic Pacific Ocean levels will be undersaturated with calcium carbonate.

Implications: Acidification of the oceans will likely wreak havoc on marine species and entire ecosystems. Given that the oceans have already absorbed a substantial amount of carbon dioxide, we have already committed to an irreversible amount of ocean acidification. As a result, we will likely see additional stress on coral reefs (already under threat due to ocean warming); other fish and aquatic organisms may be stressed as well. It is likely that rebalancing the ocean pH will take thousands -- or even hundreds of thousands of years.