Ozone and Climate: One Messy Relationship

April 28, 2008 -- Fixing the ozone hole may affect climate change -- and vice versa -- according to two new studies.

In the first case, Judith Perlwitz of the University of Colorado at Boulder and colleagues reported that as the ozone hole heals over the next century, it may cause warming over the Antarctic continent via changing wind patterns.

Her team's findings suggest that a complete regeneration of the ozone hole could result in the lower atmosphere warming over the Antarctic by as much as 5.4 degrees Fahrenheit.

The climate models used by the Intergovernmental Panel on Climate Change do not represent the stratosphere properly, said Ted Shepherd of the University of Toronto, who was not involved with the study. The effects of the ozone hole -- which occurs in the stratosphere -- on climate are not properly simulated, he said.

Perlwitz's model, however, simulates how stratospheric ozone chemistry interacts with the climate below.

When it forms in the early spring, the ozone hole cools the stratosphere, because there is less ozone to trap the sun's energy. This cooling leads to stronger westerlies, swirling winds that circle the pole, holding the cold air over the continent.

As the ozone hole closes, Perlwitz found, the stratospheric cooling decreases, weakening the westerly winds and allowing warmer air from lower latitudes into the weather systems over the continent.

The findings are published in the current issue of Geophysical Research Letters.