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article imageClimate Crisis: Ocean oxygen levels falling at unprecedented rate

By Karen Graham     Dec 8, 2019 in Environment
In a new report presented at COP25 in Madrid on Saturday, scientists warned that due to the climate crisis, our oceans are rapidly running out of oxygen - threatening fish species and disrupting marine ecosystems.
Oceans represent 97 percent of the physical habitable space we have on this planet - and the oceans are central to sustaining all life on Earth. Since 2000, considerable effort has been directed at raising awareness and understanding of the consequences of greenhouse gas emissions on the ocean.
We know that carbon dioxide emitted by human activities is causing the ocean waters to become more acidic. Eutrophication - excessive algae growth is rapidly increasing due to fertilizer run-off into waterways that eventually end up in the ocean.
And the climate crisis - coupled with record-high levels of greenhouse gasses (GHG) in the atmosphere has already raised ocean temperature levels. About 93 percent of this excess heat from the enhanced greenhouse effect over the past few decades is now stored in the ocean.
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IUCN
This is not new and has been said before. However, it does need repeating because what is happening to the Earth's life-sustaining waters is everyone's problem now, according to scientists with the International Union for Conservation of Nature (IUCN).
However, the most significant takeaway from this report is the additional focus on the more recently recognized effect of lowered oxygen resulting from ocean warming, which is now affecting enormous areas of the ocean. The report found that the oxygen level of the ocean has declined by about 2 percent since the 1950s, and the volume of water completely depleted of oxygen has quadrupled since the 1960s.
While people might say that a mere 2 percent is no big deal, there are now 700 ocean sites suffering from low oxygen - as compared to the 1960s, when there were only 45 ocean sites with low oxygen, according to CTV News Canada.
Photo of a dead zone with sediment from the Mississippi River carrying fertilizer to the Gulf of Mex...
Photo of a dead zone with sediment from the Mississippi River carrying fertilizer to the Gulf of Mexico.
NOAA
According to the study, about 50 percent of oxygen loss in the upper part of the ocean is a result of temperature increase. “Ocean deoxygenation is causing the loss of biodiversity and loss of habitats,” Minna Epps, director of the Global Marine and Polar Program at IUCN, told CTV News Channel on Saturday. “The habitats are shrinking as species are fleeing these oxygen-deprived areas, but it’s also altering the energy and the biochemical cycling.”
"Whilst we have known about dead zones in the ocean for many decades, ocean warming is now expected to further amplify deoxygenation across great swathes of the ocean," said Isabella Lövin, Minister for Environment and Energy and Deputy Prime Minister of Sweden, a major funder of the report, according to CBS News. "With this report, it is time to put ocean deoxygenation among our top priorities in order to restore ocean health."
“The very decisions being made at the climate meeting in Madrid will determine the future of our oceans, whether it will continue to be an oxygen-thriving ecosystem or if it will be irreversibly lost,” said Epps.
More about Climate crisis, Oceans, oxygen levels, Marine life, eutrophication
 
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