An international panel of marine scientists has called for urgent measures to halt ocean degradation because the rate, speed and impacts of change in the oceans are “greater, faster and more imminent than previously thought”.
Results from the latest International Programme on the State of the Ocean , carried out in collaboration with the International Union for the Conservation of Nature, go beyond the conclusions reached last week by the UN's Intergovernmental Panel on Climate Change.
The first volume of the report found that the oceans are bearing the brunt of global warming, absorbing much of the warming as well as record levels of carbon dioxide. It warned the cumulative impact of this with other “ocean stressors” is far graver than previous estimates.
Decreasing oxygen levels in the ocean caused by climate change and nitrogen run-off, combined with other chemical pollution and “rampant overfishing”, are undermining the ability of the oceans to fulfil their role as Earth’s “buffer”, according to the latest study.
'Spiralling downwards'
"The health of the ocean is spiralling downwards," said one of its lead authors, Prof Alex Rogers of Somerville College, Oxford. "The situation should be of the gravest concern to everyone since everyone will be affected by changes in the ability of the ocean to support life on Earth."
Predictions for ocean oxygen content suggest a decline of between 1 per cent and 7 per cent by 2100, due to a trend of decreasing oxygen levels in tropical oceans over the last 50 years and a “dramatic increase” in coastal eutrophication, that is the response of the ecosystem to the addition of substances.
If CO2 levels continue to rise, the study warned that there would be “extremely serious consequences for ocean life” and in turn food and coastal protection. It would also lead to extinction of species, especially on coral reefs.
Other impacts would include the disappearance of Arctic summer sea ice by about 2037 and increased venting of methane from the Arctic seabed.
The “deadly trio” of acidification, warming and deoxygenation “is seriously affecting how productive and efficient the ocean is, as temperatures, chemistry, surface stratification, nutrient and oxygen supply . . . will have cascading consequences for marine biology”.
The findings, published in the peer review journal Marine Pollution Bulletin, are part of an ongoing assessment.
