The World Avoided
CFC gases were essentially banned in 1989 through the Montreal Protocol, the world's first international environmental treaty of global scope. So, what did we avoid by banning CFCs?
Newman's group found that we avoided a previously unanticipated runaway cascade of ozone depletion, which would have led to a nearly complete loss of UV protection over the temperate and tropical regions -- not just over the poles.
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 more than 500 percent, with likely harmful effects on plants, animals, and human skin cancer rates.By the end of the collapse, the UV index would have exceeded 30 in temperate North America. A UV index greater than 10 is considered extremely dangerous.
We're talking about radiation levels similar to Hiroshima in the days following the atomic bomb (though at a different spectrum), except across the whole planet, every single day, for centuries. A walk on the beach on a sunny afternoon would have been permanently disfiguring, and possibly lethal.
Instead of this hellish scenario, CFCs peaked around the year 2000, and they're already down about four percent. The simulations predict that the ozone layer should finish healing by about 2065. Sweet.
We saved the world, at least from that particular disaster. What did we sacrifice? Basically, nothing. We had to switch to different refrigerants, and it took a few years before people figured out how to make air conditioners that worked as well as the old ones. It might even have been a net positive for the economy, since it accelerated engineering innovation and equipment upgrades, and thus efficiency.
Carbon dioxide is going to be a bigger challenge. We emit a lot more carbon than CFCs, and the things we do that emit carbon are, for the most part, much more fundamental to our economy than running refrigerators and air conditioners. Nevertheless, the Montreal Protocol is a valuable lesson. It shows that politics can influence the world in positive ways, even when everything is a mess. 1989 was not exactly a banner year for political stability, good leadership, or economic strength.