Eye on the oceans

After years of neglect, there is a growing focus on the health of the oceans, which helps sustain life on...

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After years of neglect, there is a growing focus on the health of the oceans, which helps sustain life on earth, particularly in light of the impact of rising levels of carbon dioxide (CO2) and higher temperatures.

Higher CO2 levels are causing the oceans to acidify at rates not seen in the last 20 million years, says Wendy Watson-Wright, assistant director-general and executive secretary of the Intergovernmental Oceanographic Commission of the United Nations Educational, Scientific and Cultural Organisation (UNESCO-IOC).

Several United Nations (UN) agencies led by UNESCO-IOC have developed a Blueprint for Ocean and Coastal Sustainability, to highlight the role of oceans in sustaining life.

They offer suggestions ahead of the UN Conference on Sustainable Development (UNCSD, or Rio+20).

The oceans not only supply the oxygen in every second breath we take, but also absorb at least 33 percent of the CO2 human beings produce.

The oceans have already absorbed more than 80 percent of the heat added to the climate system over the past 200 years, says the International Programme on the State of the Ocean.

As CO2 dissolves in seawater, the pH (indicator for acidity and basicity of an aqueous solution) of the water decreases - a process known as "acidification" (a lower pH value indicates an increase in acidity).

This can reduce the availability of calcium for plankton and shelled species, threatening their survival. This in turn could affect the entire ecosystem, as much of the marine food chain depends on these organisms for food.