Summary
Highlights
In 1987, an international meeting in Montreal, Canada, addressed ozone depletion, primarily caused by Freon. Representatives from about two dozen nations, including major Freon producers and users, gathered. The scientific consensus confirmed Freon as a growing problem damaging the ozone layer, necessitating a global solution. The resulting Montreal Protocol, signed by these nations, pledged to reduce Freon consumption by one-third over 13 years, aiming for a significant reduction by the year 2000. While this initial cut was insufficient to solve the problem, it marked a historic milestone as the first international agreement to address a common environmental issue.
The Montreal Protocol brought ozone depletion into mainstream news, raising public awareness. Books published around this time advised against aerosol can use to protect the ozone layer, a message that persisted in schools. While aerosol cans did use Freon, the industry quickly found alternatives, and Freon was removed from aerosol products by 1990. Despite this, the outdated advice continued to be spread, wrongly blaming the aerosol industry for ozone damage long after it had adapted.
Freon was ideal for aerosol cans due to its colorless, odorless, non-toxic, and non-flammable properties. Its replacements, however, lack some of these qualities. For example, many modern aerosol propellants, like propane, are highly flammable, posing risks such as creating a two-foot-long torch if ignited near open flames. Some alternatives are also toxic, necessitating warnings about ventilation and avoiding inhalation. While the aerosol industry successfully removed Freon, the new products are not as safe or effective.
Around 1989, news emerged of more severe ozone depletion over Antarctica. This phenomenon, inaccurately dubbed the 'Antarctic ozone hole,' was not an actual hole in the atmosphere but a significant thinning of the ozone layer. While the term was scientifically incorrect, it dramatically captured public attention, creating a sense of crisis and urgency for action against ozone depletion.
The ozone layer, though incredibly thin (if compressed to sea level, it would be only one millimeter thick), is crucial for life on Earth. It blocks 95% of the sun's harmful ultraviolet (UV) radiation. The remaining 5% is enough to cause sunburn in a short time. Without the ozone layer, 100% UV exposure would make surface life impossible, as UV radiation damages and breaks down proteins faster than living processes can repair them. The discovery of ozone depletion, even if exaggerated by the 'ozone hole' metaphor, underscored the vital need for environmental action.