The ozone hole used to be the biggest problem facing the whole planet. Without the ozone's protection, the sun's ultraviolet light was going to burn us all. But in 1987, the global community came together to agree to an unprecedented treaty to do something about it. The Montreal Protocol called for a phase-out of ozone-hole causing chemicals, which were used in refrigerators, air conditioners, and even hair spray.
If the ozone, the layer in the stratosphere that protects from the sun’s UV rays, were a hospital patient, in the three decades since the Protocol was ratified, it has gone from critical condition to now only due for once-in-awhile checkups.
And the latest checkup—a study published this week in Science—shows it is well on its way to a full recovery.
"We as a planet have avoided what would have been an environmental catastrophe," Susan Solomon, an atmospheric scientist at MIT, told Nature News. "Yay us!"
The team found that the ozone hole over Antarctica became an average of 4.5 million square kilometers small every September between 2000 and 2015. (This is despite a disruption in 2015, where a volcanic eruption in Chile caused the hole to grow temporarily.) Importantly, the scientists found that the hole—which is usually largest in October—is forming an average of 10 days later than years ago.
The Montreal Protocol is viewed as one of the most successful environmental treaties, and a model for climate change politics. Of course, there are fundamental differences: CFCs—the substances causing the ozone hole—were much less fundamental to the world economy than fossil fuels. There were also ready replacements for CFCs. But it’s still heartening to note an occasion where the world came together to tackle a pressing climate issue—and making steady progress over three decades, is actually on the course to solving it.