Report: Greenhouse gases imperil oceans’ web of life

Corals, lobsters, clams and many other ocean creatures – including some at the bottom of the food chain – may be unable to withstand the increasing acidity of the oceans brought on by growing global-warming pollution, according to a report Tuesday from the advocacy group Oceana.

Based on scientific findings of the past several years, Oceana’s report “Acid Test” examines the far-reaching consequences of the accumulation of heat-trapping gases, particularly carbon dioxide, in the world’s oceans.

A high level of carbon dioxide in seawater depletes the carbonate that marine animals need for their shells and skeletons. Creatures that are at risk if trends continue include corals, which provide habitats for about a quarter of the world’s fish; things many people like to eat, including shrimp and lobster; and pteropods, or swimming sea snails, which are an important part of the base of polar and sub-polar food chains.

Oceana, an international organization that calls for reducing pollution in order to save marine life, called for sharp reductions in carbon dioxide emissions worldwide through increased energy efficiency, a shift away from fossil fuels and the protection of forests, which absorb carbon dioxide.

“We set the goal at saving the corals,” said Jacqueline Savitz, one of the authors of the report. The goal is in line with the emissions reductions that the Intergovernmental Panel on Climate Change reported last year would be necessary: an 85 percent reduction globally from 2000 levels by 2050.

Oceana’s report said that would require a 25 percent to 40 percent reduction by industrialized countries by 2020.

The acidity of the oceans’ surfaces has increased 30 percent since before the Industrial Revolution, and the current trend would increase it 100 percent by the end of this century, exceeding levels of the past 20 million years, the report says.

“Scientists are realizing that climate change and acidification are progressing much faster than science originally predicted,” said another of the Oceana report’s authors, Ellycia Harrould-Kolieb.

Acidification adds to other problems for corals: warmer water causing bleaching, overfishing, pollution and the use of dynamite to capture fish in Asia.

Here are some of the findings about ocean acidification in the report:

-The increased amount of carbon dioxide absorbed by the oceans changes the movement of nutrients and chemicals and also affects the growth, reproduction and disease resistance of many species.

-Impacts on corals and pteropods could have ripple effects through ecosystems, ultimately harming large ocean animals and commercial fisheries.

-Cooler water holds higher levels of carbon dioxide and becomes more acidic. The current trend of carbon dioxide emissions would leave cold-water corals severely stressed by 2040, and two-thirds of them would be in a corrosive environment by the end of the century.

Renee Schoof, Miami Herald, 11 November 2008. Article.

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