Sack Lunch Seminar (SLS)

Surface westerly winds in the Southern Hemisphere have intensified over the past few decades, primarily in response to the formation of the Antarctic ozone hole, and there is intense debate on the impact of this on the ocean overturning circulation and carbon uptake. Here, we use measurements of CFC-12 made in the southern oceans in the early 1990s and mid- to late-2000s to examine changes in ocean ventilation. Our analysis of the CFC-12 data reveals a decrease in the age of subtropical mode waters and an increase in the age of circumpolar deep waters at similar depths, and suggests that the formation of the Antarctic ozone hole has caused large-scale coherent changes in the ventilation of the southern oceans.