Rising ocean-water temperatures around Antarctica are being driven by greenhouse gas emissions and ozone depletion

GATINEAU, QC, Sept. 24, 2018 /CNW/ - The temperature of ocean waters around Antarctica is rising, according to new research conducted by a team of Environment and Climate Change Canada scientists and a colleague from the Scripps Institution of Oceanography, in the United States.

Their findings, published today in the journal Nature Geoscience, are the first to show that the warming Southern Ocean temperatures over the past several decades are directly and primarily the result of increases in man-made greenhouse gas emissions. A drop in atmospheric ozone levels associated with the ozone hole is also contributing to warming.

The scientists combined an analysis of all available historical data with an advanced computer model, developed by Environment and Climate Change Canada. They also found that the waters around Antarctica are becoming less salty, consistent with known shifts in Southern Hemisphere rainfall patterns.

Quotes

"Our study shows that observed Southern Ocean warming and freshening are due to human-caused increases in greenhouses gases and stratospheric ozone depletion. Understanding changes in the Southern Ocean is important as it plays a strong role in global heat and carbon uptake, and it underlies ice sheets with the potential to impact sea-level rise. This is the first time that the separate influences of increasing greenhouse gas emissions and stratospheric ozone depletion have been detected in the Southern Ocean."
? Neil Swart, Research Scientist, Environment and Climate Change Canada

Quick Facts

• The Southern Ocean has been warming at about twice the average rate of the global ocean.
• Greenhouse gas increases are the most important driver of recent warming and freshening of the Southern Ocean.
• Ozone depletion is also driving the warming and freshening of the Southern Ocean. However, given the ozone recovery associated with the Montreal Protocol, which is now underway, it is anticipated that the impact of ozone changes on the Southern Ocean will diminish.
• On September 19 to 21, 2018, Canada hosted a meeting of G7 ministers to discuss global climate action and the health of the world's oceans.

Associated Links

• Nature Geoscience "Recent Southern Ocean warming and freshening driven by greenhouse gas emissions and ozone depletion" (English only)
• Canada and the Antarctic

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SOURCE Environment and Climate Change Canada