Thanks to Global Treaty, Ozone Layer is Recovering

By: Nick Engelfried

September 17, 2010

With activists and policymakers still struggling to reach agreement on an international treaty to curb global warming, a recent report shows how another major environmental treaty has been successful in averting harm to human health and the planet.  According to a new United Nations report, the Montreal Protocol to reduce the use of ozone-depleting substances seems to have successfully halted the shrinking of the ozone layer, and is now allowing the Earth’s protective shield of ozone to recover.

Though it is considered a harmful pollutant at ground level, ozone in the planet’s upper atmosphere provides necessary protection against the sun’s ultraviolet rays.  During the 1970s and ‘80s, scientists became concerned that chemicals then used as an ingredient for aerosols sprays, refrigerants, and even the manufacture of Styrofoam were eating away at the ozone layer—threatening to increase skin cancer, cataracts, and other human health risks.  Continued damage to the ozone layer would also have stunted the growth of vegetation worldwide, and caused mass die-offs of phytoplankton in the oceans.

In response to the threat, most countries that produced ozone depleting chemicals signed the Montreal Protocol in 1987.  This global treaty was designed to gradually phase out use of substances that harm the ozone layer, and has mostly eliminated ozone depleting chemicals like chlorofluorocarbons.  Though the treaty was strongly opposed by industries which used these compounds, predictions that the Montreal Protocol would significantly damage the economy proved unfounded. 

Meanwhile the treaty has come to be seen as a major victory for planetary health.  This week a team of United Nations scientists released a report that shows the Montreal Protocol is clearly working—though the fact that compounds like chlorofluorocarbons remain in the atmosphere a long time means the impact of eliminating them was not felt immediately.  Scientists now believe the ozone layer has stopped shrinking, and will begin to recover over the course of the next few decades.  The ozone shield in most parts of the world is expected to recover to 1980 levels by about the year 2050. 

In areas like Antarctica, where ozone damage has been particularly severe, the recovery process could take decades longer.  Yet as long as countries stay true to commitments not to use ozone-depleting substances, the Montreal Protocol should allow the entire ozone layer to eventually repair itself.

Could this success serve as a model for a treaty to curb global warming?  Global warming differs from ozone depletion in that greenhouse gases are much more widespread than compounds like chlorofluorocarbons, and fossil fuels are somewhat more complicated to replace than ozone-depleting substances.  However the Montreal Protocol does show that when presented with a large enough threat, countries from around the world can come together to avoid environmental catastrophe.  If major economies eventually forge a treaty to prevent further warming of the planet, they may indeed look to the Montreal Protocol as an example.

Photo credit: NASA Goddard Space Flight Center


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