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THE ERR UP THERE
Every child of the ’90s remembers learning about the ozone layer and hearing how everything from hairspray bottles to flatulent farm animals were at fault for depleting it.
The infamous “ozone hole” was one of the biggest stories of the decade — yet 25 years later, you’d be hard-pressed to find any mention of it in the news. Weird, right?
Keep reading to find out what on earth (and in space) happened to the ozone layer.
From the Top
It’s been a while, so let’s begin with a quick refresher on some key terms.
Ozone has a split personality in that in can be helpful or harmful depending on where it is. Stratospheric ozone (a.k.a. “good ozone”) occurs naturally in the earth’s upper atmosphere where its particles form a defensive shield that guards against the sun’s damaging ultraviolet (UV) rays.
In contrast to its protective counterpart, ground-level or “bad” ozone is a pollutant formed when man-made toxins (i.e. from car exhaust or refineries) react chemically with sunlight, particularly during very hot days.
While both types are worth knowing about, we’re focusing today’s Long Shot on stratospheric or “good” ozone.
On the Hole
Research dating back to the 1970s theorized that chlorofluorocarbons (CFCs), like those found in aerosol cans and refrigerators, could diminish the ozone layer once released into the air, but the hypothesis proved hard to, well…prove.
It wasn’t until 1985 when a group of British scientists published evidence that the earth’s ozone layer was steadily disappearing over the South Pole — findings that were later confirmed by a NASA satellite — that the so-called “ozone hole” became an international priority and part of mainstream conversation (not to mention a source of collective panic).
The crisis reached a climax in the ’80s and ’90s when the ozone depleted at a rate of 5% to 7% per decade. Since 2000 (and after a major overhaul of international standards that we’ll go into below), it has regenerated by approximately 1% to 3% per decade. Check out this timelapse to see for yourself.
You may not realize it, but our humble nation has played a central role in the global fight against ozone depletion.
In 1987, a landmark treaty called the “Montreal Protocol” was finalized with the goal of eliminating the world’s dependence on ozone depleting substances (ODS), including CFCs. The universally ratified agreement (signed by all 197 countries of the United Nations) went into force in 1989 and together with its parent treaty, the Vienna Convention for the Protection of the Ozone Layer, is considered one of the most successful international agreements of all time.
Since its inception, the Montreal Protocol has been tweaked to reflect the latest scientific research and to establish new timelines for the elimination of harmful substances. For example, the list of ODS targeted for elimination now includes 165 substances, including Hydrochlorofluorocarbons (HCFCs) — an alternative refrigerant that’s also a powerful greenhouse gas.
The Right Zone
Thanks to universal cooperation (ah, the good ol’ days when countries got along) and a multilateral commitment to ozone protection, the world is on a steady path to reversing ozone depletion and phasing out the use of ODS.
Industries have innovated technologies and cleaner substances to replace ones that have been phased out under the Montreal Protocol. For example, high-barrier tarps are now being used in the agriculture industry to reduce atmospheric emissions from alternative soil fumigants that replaced the ozone-depleting chemical, methyl bromide.
Instead of using CFCs, consumer aerosol products now use ozone-safe liquefied or compressed gasses to propel substances from their containers. Spray pumps and roll-on products have also flooded the market as an alternative to aerosol.
Scientists predict that as long as countries continue to implement measures as outlined in the Montreal Protocol, the upper ozone layer over the Northern Hemisphere should be restored in the 2030s while the Antarctic ozone hole should continue to gradually close and fully recover around 2060.