Ozone molecules are most unstable at low temperatures. This explains why holes in the ozone layer tend to form over the poles, where the atmosphere is the coldest. By trapping heat in the lower atmosphere, greenhouse gases prevent it from rising to the ozone layer. The colder the upper atmosphere stays, the more its ozone degrades. The computer model also suggested that global warming prevents heat from reaching the poles by trapping it near the equator.
Increased temperatures fuel strong east-west currents of air, called jet streams.
The jet streams form a barrier between hot tropical air and the cooler air in the Northern and Southern Hemispheres. These barriers prevent warmer air from reaching the poles. The chilly polar conditions, in turn, fuel ozone destruction. The model predicted maximum ozone loss would occur between the years 2010 and 2019. Other scientists cautioned against relying too heavily upon the predictions.