The hole in the ozone layer was once the most talked about facet of environmentalism.
Since the link was established between chlorofluorocarbons (CFCs) and ozone damage, many things have changed, but industrialisation has increased. As a result it may come to a surprise to hear that the damage done is reversible, and that the results are already presenting themselves.
Estimates have been made which state that, by the end of this century, the hole will have been completely fixed.
A lot of the credit for the environmental progress has been attributed to the 1987 Montreal Protocol, a landmark agreement which outlawed the use of CFCs in aerosol cans and refrigeration units. Prompted by awareness campaigns and changes within consumer habits, the ruling created a massive shift in CFC use and subsequent environmentalist education.
The hole in the ozone layer, which opens for three months every year between August and October, has been the focus of scientists for decades, but it was in 2016 that the first improvements were published in Science magazine.
“The authors, from NASA’s Goddard Spaceflight Center, made use of data collected by NASA’s Aura satellite, which measures a suite of trace atmospheric gases to understand changes to the ozone layer, Earth’s climate, and air pollution.
“It kind of surprised me that no one had done this,” lead study author Susan Strahan told Earther. “The data is there if you’re careful about what data to use.”
Strahan and her colleague Anne Douglass looked at changing ozone levels above Antarctica throughout the austral winter from 2005 to 2016, and found that ozone depletion had declined by about 20 percent. Then, they looked at levels of hydrochloric acid in the stratosphere at the end of winter, an indicator of how much ozone had been destroyed by CFCs.
Bill Randall, an atmospheric scientist at the University Corporation for Atmospheric Research who was not involved with the study, told Earther he thought the paper’s analysis was “very well done.”
“They’re seeing net decreases in chlorine that are very consistent with the Montreal Protocol,” he said. “That’s a big take home message, that the Montreal Protocol is doing what we think it should be doing.””
What this displays is that certain elements of environmental damage are reversible, but not all. The impetus is on reducing and minimising further damage, to ensure a brighter and safer future for generations to come.