Antarctica Ozone Layer Thinning Alters Ocean Circulation: Study

A breakthrough discovery made by a Johns Hopkins earth scientist shows that the hole in the Antarctic ozone layer has triggered major alterations in the southern oceans, reports the official website. These changes can alter the amount of CO2 in the atmosphere and thereby have a severe impact on climate change globally.

According to the findings, the subtropical intermediate waters of the southern ocean have become 'younger', while the circumpolar waters have gotten 'older'. These changes are constant because the surface winds have become stronger as a result of ozone depletion.

"This matters because the southern oceans play an important role in the uptake of heat and carbon dioxide, so any changes in southern ocean circulation have the potential to change the global climate," Darryn W. Waugh, of the Morton K. Blaustein Department of Earth and Planetary Sciences at Johns Hopkins' Krieger School of Arts and Sciences, said in a news statement.

In order to substantiate their hypothesis, the team depended on the measurement of the cholofluorocarbon-12 (CFC-12), a chemical compound present in the southern oceans. These measurements were taken in the early 1990s to mid 2000s. CFC-12 was initially produced in the 1930s but its concentration multiplied over a period of time. In the 1990s, it was phased out by the Montreal Protocol on substances that deplete the ozone layer. 

Based on previous measurements, the team was able to understand how changes occurred, and how rapidly the surface waters mix with the interior of the southern ocean. The concentration of CFCs at the ocean surface increased in length with those in the atmosphere. They concluded that the more the concentration of CFC-12 in the oceans' interior, the more recently these waters were at the surface.

The study reports that, "As the concentrations of CFCs at the ocean surface increase in parallel with those in the atmosphere, they surmised that the higher the concentration of CFC-12 in the ocean's interior the more recently that water was at the surface."

The paper is being published in the journal Science.