A United Nations assessment released on Monday confirmed the good news for the environment: the ozone hole that has threatened Earth since the 1980s is becoming smaller.
Global alarm and action were sparked by the discovery of a sizable hole in the gaseous shield that shields life on Earth from ultraviolet radiation.
British geophysicist Joseph Farman carries out research with weather balloons between 1975 and 1984 that reveals a slow and unsettling decline in the ozone layer in the stratosphere over the Halley Bay research station in the Antarctic.
This “hole,” which often manifests in the spring in the southern hemisphere, adds to the research of two chemists from the University of California, Mario Molina and Sherwood Rowland.
They had suggested in 1974 that the ozone layer is being destroyed by chlorofluorocarbons (CFCs), which are often used in refrigeration as well as hairspray and other aerosols. The two scientists are awarded the 1995 Nobel Prize in Chemistry.
The Vienna Convention for the Protection of the Ozone Layer, the first international agreement on the subject, is signed in March 1985 by 28 nations. Its members are obligated to monitor ozone depletion and its effects on human health and the environment.
In 1986, the agreement is ratified by the United States, which had outlawed the use of CFCs in aerosols in 1978. The Vienna Accord lays the groundwork for the historic Montreal Protocol, which establishes goals for gradually phasing out the production and consumption of ozone-depleting chemicals, two years later.
One of the most effective environmental treaties ever, it was first signed by 24 nations, including the former European Economic Community (now the EU).
Over a ten-year period, it seeks to reduce usage of CFCs and halon gases, which are frequently found in fire extinguishers.
After scientists report that the hole over the Antarctic has grown even larger in late 1987, the major chemical companies agree to create less dangerous CFC substitutes.
A thinned area in the ozone layer above the Arctic is also noticed in early 1989.
The Montreal Protocol is strengthened in 1990 to mandate that by the year 2000, all CFC production must cease in industrialized nations.
Rich nations also agree to contribute to the costs of the Protocol’s implementation in less developed nations.
China ratifies the agreement a year later. In 1992, India joins.
By the end of 1995, the European Union had completely outlawed CFCs and had started to phase out their replacement, the potent greenhouse gases known as HCFCs (hydrochlorofluorocarbons, used in air conditioning and refrigeration), which also damage the ozone layer.
At a conference, industrialized countries agree to ban HCFCs by 2020.Then the biggest ever hole seen in the ozone layer over the Antarctic is recorded, late September 2006.
In September 2007, a historic accord is reached in Montreal to advance by 10 years to 2030 the elimination of HCFCs by developing states.
June 2016, in science magazine, the US and UK researcher wrote that the hole over the Antarctic is shrinking, and they expect it to completely heal by the year 2050.
Now, on January 2023, the UN announces that the ozone layer is on track to fully recover within four decades. But it warns controversial geo-engineering schemes to blunt global warming could reverse that progress.
