How has the climate been changing in Antarctica?
In our 2002 Nature paper, we talked about the trends over the last 14 years in the Dry Valleys. It showed a cooling in the Dry Valleys, which is still going on today. With the cooling you get dropping lake levels and thicker ice covers, and with thicker ice covers there’s less sunlight going into the lakes, so the productivity goes down. In the soil environment, there was a decrease in the numbers of nematodes, and that’s still going on today as well. It’s kind of mysterious. We also went out and looked at what’s been going on continent-wide. We teamed up with John Walsh, now at the University of Alaska Fairbanks, who does more large-scale climate measurements, and we showed that the entire continent—about 60 percent of it—has, over the previous 30 years, been cooling. How do you explain the cooling trend? One of the theories is that there’s an ozone hole over Antarctica, and it’s causing the cooler temperatures, because ozone is a greenhouse gas. If you have a hole over Antarctica, yo
