Verdenshavenes tilstand har stort set ikke været på bordet under klimaforhandlingerne, skønt de over de seneste 200 år har optaget 80 procent af al den ekstra varme, menneskeheden har pumpet ind i klimasystemerne – og prisen herfor kan blive høj.
JOHANNESBURG, 5 April 2012 (IRIN) – The tide seems to be finally turning for the oceans. 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 (forsure) 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 UN Educational, Scientific and Cultural Organization (UNESCO-IOC).
Several 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 (ilt) 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 (surhedsgrad) and basicity of an aqueous solution (vandig opløsning)) 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 (skaldyr), threatening their survival. This in turn could affect the entire ecosystem, as much of the marine food chain depends on these organisms for food.
Acidification impact
Studies on ocean acidification’s potential impact on marine life and ecosytems have been presented regularly at side events during UN climate talks, but have never made it to the main negotiations, even though such talks frequently mention the impact of high CO2 on sea-level rise.
Mean ocean pH has decreased (which means the acidity in water has increased) by 30 percent since 1751 and if we continue to emit CO2 at the same rate, the pH could decrease by a further 150-200 percent by 2100, says a new book, Valuing the Ocean, by the Stockholm Environment Institute.
“This rate of change is around 10 times faster than that caused by any other event experienced by the ocean in the last 65 million years,” it says.
Yet only one percent of the oceans are protected, according to UNESCO-IOC.
Proposals
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http://www.irinnews.org/Report/95245/CLIMATE-CHANGE-Eye-on-the-oceans
