Remember the Ozone Hole? It was one of the big environmental problems of the 20th century that seemed to go along with all the other reasons that our planet was in trouble. It was a reason all we light-skinned people, especially the Aussies, were going to get skin cancer and cataracts. According to the Ozone Hole website, the ozone hole of 2006, over Antarctica, was the biggest ever:
So what is ozone and why is a hole in it bad?
Ozone is a gas made up of three oxygen atoms, with the chemical formula O3. (The normal oxygen we need to breathe is O2). It occurs naturally in small amounts in the upper atmosphere (also known as the stratosphere) and forms a thin layer covering the entire planet. This stratospheric ozone layer (“good ozone”) protects life on Earth from the Sun’s ultraviolet (UV) rays. Near the Earth’s surface, however, ozone is created locally by chemical reactions between air pollutants. High concentrations of ozone down here on the ground are toxic (“bad ozone”). The Ozone Hole is a thinning of the layer of protective “good ozone” that allows too much UV radiation to reach Earth’s surface.
Why did the layer get thinner?
Some chemicals that were used in spray cans and in air conditioners and refrigerators contain chlorine and bromine atoms, and these atoms are released when the chemicals come into contact with UV light. Then, when these chlorine and bromine atoms drift up into the stratosphere and encounter the ozone layer, they destroy it. A single chlorine atom can destroy over 100,000 ozone molecules. The most common of these ozone-depleting chemicals are called CFCs.
In 1985, the Montreal Protocol regulating CFCs was introduced. This is an international commitment to phase out ozone-depleting chemicals that was ratified by all UN countries. On January 4 of 2018, the first study was published that used measurements of the chemical composition inside the ozone hole to confirm that not only is ozone depletion decreasing, but that the decrease is caused by the reduction in CFCs. In other words, the Montreal Protocol is working! NASA Study: First Direct Proof of Ozone Hole Recovery Due to Chemicals Ban.
This is only a first step and more needs to be done, because CFCs last a long time and the CFCs made in the last century are still around causing trouble in this one. But it is still a good example of how science can influence governments’ decision-making, and how the nations of the world can work together to solve big environmental problems. May our leaders learn from this example!
This post is part of the We Are the World Blogfest, a monthly event created by Damyanti Biswas and Belinda Witzenhausen to showcase stories of hope and light. The #WATWB cohosts for this month are: Shilpa Garg, Simon Falk, Lynn Hallbrooks, Eric Lahti, Damyanti Biswas and Guilie Castillo. Please link to them in your #WATWB posts and go say hi!