Ozone layer changes could enhance UV radiation in tropics

“Climate change is an established fact, but scientists are only just beginning to understand its regional manifestations,” said Michaela Hegglin, a physics researcher at the University of Toronto (U-T) and lead study author.

Using a sophisticated computer model, Hegglin and U-T physicist Theodore Shepherd determined that 21st-century climate change will alter atmospheric circulation, increasing the flux of ozone from the upper to the lower atmosphere and shifting the distribution of ozone within the upper atmosphere.

The result will be a change in the amount of UV radiation reaching the earth’s surface which varies dramatically between regions.

That is up to a 20 percent increase over southern high latitudes during spring and summer, and a nine percent decrease in UV radiation over northern high latitudes, by the end of the century.

While the effects of increased UV have been widely studied because of the problem of ozone depletion, decreased UV could have adverse effects too, e.g. on vitamin D production for people in regions with limited sunlight such as the northern high latitudes.

“Both human and ecosystem health are affected by air quality and by UV radiation,” said Shepherd.

“While there has been much research on the impact of climate change on air quality, our work shows that this research needs to include the effect of changes in stratospheric ozone," he added.

The study was published in the September issue of Nature Geoscience.