An assessment compiled by the United Nations and other international organizations has found that the hole in the ozone layer, considered the most significant environmental emergency of the 1980s, is expected to be completely repaired in most of the world by 2040.
The assessment also found that the ozone layer loss in the Arctic and Antarctic should be healed between 2045 and 2065.
Ozone layer holes, thin regions of the ozone layer in Earth’s stratosphere, occur yearly in both hemispheres. The phenomenon is more pronounced in the polar regions.
Depletion of the ozone layer allows ultraviolet radiation from the sun to reach the Earth’s surface, causing potential harm to humans and animals alike.See Also:News Briefs
According to the E.U.’s Copernicus Atmosphere Monitoring Service, the ozone hole over the southern hemisphere reached a maximum size of 28.4 million square kilometers (an area equivalent to almost seven times the territory of the E.U.) in September 2000. It stopped increasing in size in subsequent years.
The U.N. assessment attributed the predicted success of restoring the Earth’s ozone layer to the Montreal Protocol of 1987. This was an international agreement aimed at eliminating ozone-depleting chemicals, such as CFCs (chlorofluorocarbons), commonly found in fridges, air conditioners and spray cans.
“[The Montreal agreement should be considered] the most successful environmental treaty in history and offers encouragement that countries of the world can come together and decide an outcome and act on it,” said David Fahey, a scientist at the National Oceanic and Atmospheric Administration (NOAA) and the lead author of the assessment.
Experts also believe the actions taken by nations to restore the planet’s ozone layer can be used as a guide for tackling climate change.
“Ozone action sets a precedent for climate action,” said Petteri Taalas, secretary-general of the World Meteorological Organization. “Our success in phasing out ozone-eating chemicals shows us what can and must be done as a matter of urgency to transition away from fossil fuels, reduce greenhouse gasses and so limit temperature increase.”
According to Fahey, however, reducing fossil fuel emissions requires a much more decisive approach than CFCs.
“Carbon dioxide is another order of magnitude when it comes to its longevity, which is sobering,” he said. “Getting every person on the planet to stop burning fossil fuels is a vastly different challenge.”
The assessment’s authors also warned that proposed strategies to mitigate global warming, such as spraying millions of tons of sulfur dioxide in the stratosphere (a technique known as a stratospheric aerosol injection), could adversely impact the ozone layer’s recovery.