Projections say that by the end of the 21st century, oceans worldwide will see an increase in acidity of 150%. (Photo: Hall-Spencer Nature/UNEP/FIS)
Ocean acidification threatens food security: UN
Friday, December 03, 2010, 23:10 (GMT + 9)
Growing greenhouse gas emissions may have more widespread and complex effects on ocean health than previously anticipated as the chemistry of the oceans is changed at a rate unseen for 65 million years, according to the United Nations Environment Programme’s (UNEP) “Environmental Consequences of Ocean Acidification” report released at a climate convention meeting in Mexico.
The report confirms worries that corals, shellfish and other organisms may have an increasingly difficult time surviving due to weakening skeletons, and demonstrates that ocean acidification combined with ocean warming would lower the range of temperatures in which crabs and other animals can thrive.
This could powerfully affect, among other factors, catches of shellfish; species reliant on coral reefs and those such as salmon that feed on shell-building organisms lower down the food chain.
Further, other research is highlighting new concerns, including findings that species such as clown fish may find it tougher to avoid predators.
The food and livelihood security of billions of people could be compromised if other fish react the same way. Fish including shellfish make up 15 per cent of animal protein for 3 billion people across the globe, and another 1 billion people rely on fisheries for their main source of protein.
“Whether ocean acidification on its own proves to be a major or a minor challenge to the marine environment and its food chain is to date unknown,” said Achim Steiner, UN Under-Secretary General and UNEP Executive Director.
“But the phenomenon comes against a backdrop of already stressed seas and oceans as a result of over-fishing to other forms of environmental degradation. Thus the public might quite rightly ask how many red flags do governments need to see before the message to act gets through," Steiner added.
Carol Turley, a senior scientist at the laboratory; Knowledge Exchange Coordinator for the UK Ocean Acidification Research Programme and lead author of the new report, said some research showed that adult lobsters might actually boost shell-building due to falling pH levels and the juveniles’ ability to build healthy skeletons would be impaired.
"Scientists will need to study all parts of the life-cycle to see whether certain forms are more or less vulnerable. Meanwhile, the ability, or inability, to build calcium-based skeletons may not be the only impact of acidification on the health and viability of an organism: brittle stars perhaps being a case in point," said Turley.
The report urges governments, policymakers and others to consider various actions including:
- Rapid and hefty cuts to man-made CO2 emissions to curb ocean acidification;
- Establish the vulnerability of human communities dependent on marine resources to ocean acidification;
- Identify species more flexible to change and assess how they may affect food security;
- Reduce pressures on fish stocks;
- Review options for developing environmentally sustainable aquaculture using species more resistant to lowered pH
Projections based on current rates of CO2 emissions concluded that by the end of the 21st century, oceans worldwide will see an increase in acidity of 150 per cent.
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By Natalia Real