New study: Substantial irreversible damage to ocean ecosystems

By 2050, ocean acidity could increase by 150 percent. This increase is 100 times faster than any change in acidity experienced in the marine environment over the last 20 million years.

14/12/2009 - The secretariat of the Convention on Biological Diversity (CBD) released Monday a major study in collaboration with the UNEP World Conservation Monitoring Centre (UNEP-WCMC).

According to the study, seas and oceans absorb approximately one quarter of the carbon dioxide emitted to the atmosphere from the burning of fossil fuels, deforestation and other human activities. As more and more carbon dioxide has been emitted into the atmosphere, the oceans have absorbed greater amounts at increasingly rapid rates.

Without this level of absorption by the oceans, atmospheric CO2 levels would be significantly higher than at present and the effects of global climate change would be more marked.

However, the absorption of atmospheric CO2 has resulted in changes to the chemical balance of the oceans, causing them to become more acidic.

It is predicted that by 2050, ocean acidity could increase by 150 percent. This dramatic increase is 100 times faster than any change in acidity experienced in the marine environment over the last 20 million years, giving little time for evolutionary adaptation within biological systems.

"Ocean acidification is irreversible on timescales of at least tens of thousands of years, and substantial damage to ocean ecosystems can only be avoided by urgent and rapid reductions in global emissions of CO2. Attention must be given for integration of this critical issue at the global climate change debate in Copenhagen," said Mr. Ahmed Djoghlaf, executive secretary of the convention.

"This CBD study provides a valuable synthesis of scientific information on the impacts of ocean acidification, based on the analysis of more than 300 scientific literatures, and it describes an alarming picture of possible ecological scenarios and adverse impacts of ocean acidification on marine biodiversity," he added.

Among other findings, the study shows that increasing ocean acidification will mean that by 2100 some 70 percent of cold water corals, a key refuge and feeding ground for commercial fish species, will be exposed to corrosive waters.

Do UNFCCC