How We Solved the Hole in the Ozone
The most striking thing was the solitude. As the airplane thundered across an unsettled sky toward Antarctica, I stared out the window at the landscape of shifting ice floes and dark ocean. There were no roads, no settlements, no structures of any kind—not even the occasional lonely ship on the south polar seas. As we approached the continent, the last rays of sunlight faded, replaced by a diffuse blue and purple twilight. That’s when I realized we really were on our way to the last place on Earth.
Just the year before, I’d been happily sitting at my desk in my warm and cozy office, where I studied stratospheric chemistry using computer models. The kingpin molecule in that chemistry is ozone, a highly reactive gas produced from oxygen that has unique abilities to absorb high-energy ultraviolet light. Earth’s fragile ozone shield stands between us and oblivion from the sun’s damaging rays and is what first allowed life to crawl out of the protective ocean and walk on land. A “layer” of ozone formed naturally in the stratosphere as oxygen evolved on Earth, some 10 to 30 miles over our heads.
Persistence is a property that should arouse uneasiness every time we encounter it.
But human activities can release a range of chemicals that eat away at it. The most damaging of these are compounds containing chlorine and bromine. Scientists had been expecting some ozone depletion due to human use of chlorofluorocarbon (CFC) chemicals—a small percentage, and a hundred years in the
