New simulation shows consequences of a world without Earth’s natural sunscreen

The year is 2065. Nearly two-thirds of Earth’s ozone is gone — not just over the poles, but everywhere. The infamous ozone hole over Antarctica, first discovered in the 1980s, is a year-round fixture, with a twin over the North Pole. The ultraviolet (UV) radiation falling on mid-latitude cities like Washington, D.C., is strong enough to cause sunburn in just five minutes. DNA-mutating UV radiation is up 650 percent, with likely harmful effects on plants, animals and human skin cancer rates.

Such is the world we would have inherited if 193 nations had not agreed to ban ozone-depleting substances, according to atmospheric chemists at NASA’s Goddard Space Flight Center, Greenbelt, Md., Johns Hopkins University, Baltimore, and the Netherlands Environmental Assessment Agency, Bilthoven.

Led by Goddard scientist Paul Newman, the team simulated “what might have been” if chlorofluorocarbons (CFCs) and similar chemicals were not banned through the treaty known as the Montreal Protocol. The simulation used a comprehensive model that included atmospheric chemical effects, wind changes, and radiation changes. The analysis has been published online in the journal Atmospheric Chemistry and Physics.

In the new analysis, Newman and colleagues “set out to predict ozone losses as if nothing had been done to stop them.” Their “world avoided” simulation took months of computer time to process.

“We simulated a world avoided,” said Newman, “and it’s a world we should be glad we avoided.”

EurekAlert