Planetary Waves and Ozone Holes

Spring is the season when sunlight can trigger the chemistry of stratospheric ozone destruction. But Earth's two poles react differently to the coming of spring. Springtime in Antarctica heralds a large ozone hole, while springtime in the Arctic (six months later) often brings above-average ozone concentrations. Global warming could alter this familiar pattern, though, by chilling the northern stratosphere and producing an ozone hole there as well. [more]

Climate changes associated with global warming might also weaken planetary waves - so say some computer models. The cooling of the stratosphere due to this indirect effect could be more significant than the cooling caused directly by greenhouse gases. However, Newman cautions that this result is still very uncertain because of questions about the fidelity of the computer models.

Another wild card is the changing concentration of ozone-destroying pollutants. The number of CFC molecules in the lower atmosphere, for example, peaked in 1994 and have since declined. Computer simulations show that CFCs in the high stratosphere could return to pre-1980 levels in 30 to 50 years. Because climate change occurs on similar time scales, it's difficult to say which trend would dominate: the cooling of the stratosphere, which would encourage an Arctic ozone hole, or the decline of CFCs, which would suppress it.

Perhaps only time will tell if far-northern cities will continue to enjoy the good fortune of year-round polar ozone. But many researchers aren't content to wait decades for an answer. With the aid of Earth-watching satellites and ever-improving computer climate models, scientists hope to unravel the puzzle of Arctic ozone before it becomes a problem.

After all, one planetary ozone hole is more than enough!