Climate Change: Ocean Collapse irreversible?

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08.07.2015 09:44
Kategorie: News

Oceans Will Collapse If Greenhouse Gas Emissions Are Not Reduced

Korallen, Bermuda - © A.Venn (www.awi.de)
It's been confirmed: Even if we were to reduce our global emission of greenhouse gases, there will still be a fundamental change in our oceans.

Since pre-industrial times, the carbon dioxide concentration in the earth's atmosphere has increased from 278 to 400 ppm (parts per million). That's an increase of 40 percent in such a short time span!

As a result, ocean temperatures up to depths of 700 metres have risen. The marine animals within the 400 kilometres depth have migrated towards to the poles within a decade, where the waters are cooler. Calcareous remnants of corals and seashells have deteriorated at a faster rate due to the increased acidification, while the ice in Greenland and West Antarctica continues to melt, contributing to rising sea levels.

"If we manage to limit the rise in air temperature in 2100 to less than 2 degrees Celsius, the risk increases especially for tropical corals and shells in the low to mid-latitudes to a critical level. Other risks remain moderate in this case," said the study's lead author Jean-Pierre Gattuso.

In short, the changing biological, physical and chemical processes in the marine environment have caused far-reaching consequences for marine life, and for us.

Korallenriffe in Gefahr - © D.Laffoley (www.awi.de)
These were some revelations described in a new study published in the journal Science on 2 July 2015. The research team had assessed the latest findings on the impact of climate change on the seas and then showed how the ocean's ecosystems would be altered if current levels of carbon dioxide emissions persisted.

The role of the oceans in regulating the carbon dioxide emissions cannot be underestimated. Describing the oceans' function as a refrigerator and 'carbon dioxide storage', co-author Professor Hans-Otto Pörtner said that since the 1970s, about 93 percent of the heat had been captured by the greenhouse effect.

Maintaining the current level of yearly carbon dioxide emissions of 36 gigatonnes (as of 2013) will cause the situation in the oceans to worsen. "If we continue with business as usual, the changes by the end of this century, nearly all ecosystems of the oceans and affected marine life would suffer lasting damage," said Professor Pörtner. This in turn could have a serious impact in our relationship with the oceans, be it in fishing, tourism or coastal protection.


Source: Alfred-Wegener-Institut

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