Ocean Acidification--A Basic Environmental Change

One inevitable long-term change due to humanity's two-century carbon orgy is seen in the chemistry of seawater. An upcoming report from the U.S. National Academy of Sciences reviews the issues (access report summary here, registration required).

Ocean Acidification

The pH of the ocean surface waters is around 8.1. Thus oceans are not acid, they are basic. A better term might be "ocean debasification". Be that as it may, about one-third of the carbon dioxide we have been dumping into the atmosphere over the past 200 years has ended up dissolving in the oceans, increasing their surface pH from 8.2 to 8.1, and model projections show an additional 0.2-0.3 drop by the end of the century, "even under optimistic scenarios". "The rate of this change exceeds any known change in ocean chemistry for at least 800,000 years." Not good.

"Atmospheric CO₂ increased over thousands of years during the glacial/interglacial cycles of the past 800,000 years, slow enough for the CaCO₃ cycle to compensate and maintain near constant pH." But currently "the concentration of atmospheric CO₂ is rising too rapidly for natural, CaCO₃-cycle processes to maintain the pH of the ocean. As a consequence, the average pH of the ocean will continue to decrease as the surface ocean absorbs more atmospheric CO₂."

"It is currently not known if and how various marine organisms will ultimately acclimate or adapt to the chemical changes resulting from acidification, but existing data suggest that there likely will be ecological winners and losers, leading to shifts in the composition and functioning of many marine ecosystems. It is also not known how these changes will interact with other environmental stressors such as climate change, overfishing, and pollution. Most importantly, despite the potential for socioeconomic impacts to occur in coral reef systems, aquaculture, fisheries, and other sectors, there is not currently enough information to assess these impacts, much less develop plans to mitigate or adapt to them." Like driving fast at night on a curvy road with no headlights.

The NAS report recommends a lot more research funding on this topic, so we will at least have a flashlight to illuminate the road ahead, since it doesn't look like anyone is willing to consider the option of slowing down.

This Wikipedia article gives links to additional information sources.