2070 is shaping up to be a great year for Mother Earth.
That's when NASA scientists are predicting the hole in the ozone layer might finally make a full recovery. Researchers announced their conclusion, in addition to other findings, in a presentation Wednesday during the annual American Geophysical Union meeting in San Francisco.
The team of scientists specifically looked at the chemical composition of the ozone hole, which has shifted in both size and depth since the passing of the Montreal Protocol in 1987. The agreement banned its 197 signatory countries from using chemicals, like chlorofluorocarbons (CFCs), that break down into chlorine in the upper atmosphere and harm the ozone layer.
They found that, while levels of chlorine in the atmosphere have indeed decreased as a result of the protocol, it's too soon to tie them to a healthier ozone layer.
"Ozone holes with smaller areas and a larger total amount of ozone are not necessarily evidence of recovery attributable to the expected chlorine decline," Susan Strahan of NASA's Goddard Space Flight Center explained in a media briefing. "That assumption is like trying to understand what's wrong with your car's engine without lifting the hood."
Instead, the scientists believe the most recent ozone hole changes, including both the largest hole ever, in 2006, and one of the smallest holes, in 2012, are primarily due to weather. Strong winds have the ability to move ozone in large quantities, effectively blocking the hole some years, while failing to block it in others.
“At the moment, it is winds and temperatures that are really controlling how big [the ozone hole] is,” Strahan told the BBC.
LiveScience reports weather is expected to be the predominant factor in the ozone hole's size until 2025, at which point CFCs will have dropped enough as a result of the Montreal Protocol to become noticeable.
By 2070, however, the ozone hole is expected to have made a full recovery.
"It’s not going to be a smooth ride," Strahan cautioned the Los Angeles Times. "There will be some bumps in the road, but overall the trend is downward."