Daily post

The Antarctic ozone hole, a global environmental success story (sorta)

Two years after an incriminating paper in Nature, 27 countries signed the Montreal Protocol to limit CFCs.

Once upon a time, the world acted quickly when faced with challenges to the environment.

In the early 1980s, scientists from the Japan Meteorological Agency and the British Antarctic Survey discovered “unusually low total ozone” over the Antarctic during late winter/early spring (September, October, and November).

Ozone is a naturally occurring oxygen compound high in the upper Earth atmosphere.

In May 1985, Nature published a paper by three scientists from the British Antarctic Survey that announced the “unexpected discovery of a hole in the atmospheric ozone layer over the Antarctic.

The culprit: chlorofluorocarbons (CFCs), nontoxic, nonflammable chemicals composed of carbon, chlorine and fluorine.

At the time, these three chemicals were widely used as refrigerants. In addition, CFCs were involved in the manufacture of aerosol sprays and were used as solvents. Their negative impact is to “erode the ozone as the sun emerges over the Antarctic after the polar winter.”

Two years after that Nature paper, 27 countries signed an international treaty, the Montreal Protocol, which committed these countries to reduce their use of CFCs (production levels, 1986 base year) by 50% before the year 1998.

On 3 March 1989, representatives from the 12 European Community countries went further. They agreed to ban all production of CFCs by the year 2000.

The following year, the world came together again to refine the Montreal Protocol (the London Amendment). The result: a ban on the use of CFCs in 10 years (by 2000) for industrialized countries and in 20 years (by 2010) for developing countries.

The Montreal Protocol “regulates the production and consumption of nearly 100 man-made chemicals referred to as ozone depleting substances (ODS).” Additional amendments followed in 1992, 1997, 1999 and 2016.

Not only did we act quickly and decisively, scientists say that our actions worked. According to the US EPA, “emissions of ODS are falling and the ozone layer is expected to be fully healed near the middle of the 21st century.” However, that “near the middle” is now expected to be no sooner than 2070.

In the meantime, climate change accelerated.

In the September-November 2021 season, at its peak the hole was “roughly the size of North America.” It reached that maximum size on 07 October 2021; this the 13th largest since 1979.

“This is a large ozone hole because of the colder than average 2021 stratospheric conditions, and without a Montreal Protocol, it would have been much larger,” according to Paul Newman, chief scientist for Earth sciences at NASA’s Goddard Space Flight Center.

Ozone 2021
The 2021 Antarctic ozone hole reached its maximum area on 07 October 2021 and is the 13th-largest hole since 1979.

#scitech, #computing, #society (041/365)


Daily posts, 2022-2023

By Kathy E. Gill

Digital evangelist, speaker, writer, educator. Transplanted Southerner; teach newbies to ride motorcycles! @kegill

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.