Notes:
Key Findings from the Report
Around 25 per cent of the world’s C02 emissions are being absorbed into the seas and oceans where it converts to carbonic acid. This is lowering the pH of the oceans and affecting its chemistry. For example, the concentrations of carbonate ions are decreasing and this is linked to the ability of many marine organisms to build reefs and shells.
- The report says that the chemistry of the oceans is being altered at a speed not seen for 65 million years since the extinction of the dinosaurs;
- The mean pH of the marine world has decreased by 30 per cent and the concentration of carbonate ions has fallen by 16 per cent since the industrial revolution;
- Based on current rates of CO2 emissions, projections show that by the end of the 21st century, global ocean pH will decrease by a further 0.3 units, which represents a total increase in acidity of 150 per cent.
Fish including shellfish contribute 15 per cent of animal protein for three billion people worldwide, and a further one billion people rely on fisheries for their primary source of protein.
- The report says that many marine organisms have ways of compensating for changes in seawater chemistry, although they may have to spend more energy doing this in an increasingly more acidic ocean;
- However, studies of mussels and sea urchin species have shown that they have only a partial or no compensation mechanism, potentially making them more vulnerable.
Around 80 per cent of fish catches occur in just 10 per cent of the oceans, including key areas such as Continental shelves and estuaries.
- The report says that “many of these areas are also projected to be very vulnerable to ocean acidification this century”.
The aquaculture industry is the fastest growing food producer worldwide, increasing at a rate of 7 per cent per annum and the proportion of fish produced by aquaculture and consumed by humans worldwide has risen to 50 per cent of total production.
- The report says that these industries are now at risk from future ocean acidification both directly through the impact on the organisms themselves and indirectly through the food webs and habitats they depend on.
Tropical reefs provide shelter and food for an estimated 25 per cent of known marine fish species, and account for between 9 and 12 per cent of world fish landings. Consequently, these coral reefs provide food and livelihood security for some 500 million people worldwide.
- The report says it is anticipated that future ocean acidification is likely to affect adult and juvenile coral growth and recruitment, coralline red algae growth, reef structural integrity and potentially even the density of bio-eroding grazers and predators.
The Report “UNEP Emerging Issues – Environmental Consequences of Ocean Acidification: A Threat to Food Security” is available at:
http://www.unep.org/dewa/pdf/Environmental_Consequences_of_Ocean_Acidification.pdf
The report is being launched at the 16th Conference of the Parties to the UN Framework Convention on Climate Change taking place in Cancun, Mexico, from 29 November to 10 December 2010.
Source: UNEP Press Release dated December 2, 2010.
