It is a (rare) great day in environmental news! According to a United Nations report, the ozone layer is “showing its first sign of recovery after years of dangerous depletion”. In fact, scientists estimate that ozone levels climbed 4% in key mid-northern latitudes from 2000 to 2013, representing a “significant and sustained increase”.
The ozone layer, or ozone shield, is a layer in the earth’s stratosphere that absorbs most of the sun’s ultraviolet (UV) radiation. In excess, this radiation can “penetrate organisms’ protective layers, like skin, damaging DNA molecules in plants and animals”. Consequently, scientists have linked ozone depletion to skin cancer, cataracts, crop damage, and the destabilization of the aquatic food chain. In fact, the UN projects that restoring the ozone layer will prevent 2 million cases of skin cancer annually by 2030.
Scientists are calling the improvement a “victory for diplomacy and for science”. After all, the 1987 Montreal Protocol – ratified by all 197 UN members – “banned or phased out ozone depleting chemicals, including chlorofluorocarbons (CFCs)” used in refrigerators, air conditioners and aerosol cans. In the words of Achim Steiner, Executive Director of the U.N. Environment Program, banning such chemicals is “one of the great success stories of international collective action in addressing a global environmental change phenomenon.”
So what made this collective action possible (when it eludes us on climate change)? Political scientists point to numerous factors. First, unlike slowly rising temperatures, ozone depletion was visible. Satellite images in the 1980s showed “shocking” ozone holes over the Polar Regions. Similarly, there were clear causal links between ozone depletion and its human impacts. People better understood how the ozone holes (rather than climate change) could impact them directly.
Additionally, several major countries were quick to join the fight against ozone depletion. The US, for example, ratified the Montreal Protocol in early 1988 (yet never ratified the Kyoto Protocol). This, in turn, encouraged other countries to ratify, largely due to the protocol’s trade provisions.
Finally, unlike climate change, ozone depletion could be traced to a limited set of chemicals produced by a small number of companies. Though some of the companies (e.g. Du Pont) lobbied strongly against the Montreal Protocol, they ultimately succeeded in developing superior chemical substitutes. In this regard, some say that the Protocol benefitted both environment and industry.
But don’t throw away your sunscreen just yet. According to a 300 scientist panel, the ozone layer is “just starting to heal”. The layer is still about 6% thinner than in the 1980s and the ozone hole is about 20 million square kilometers (compared to 30 million in 2006). At this rate, the UN believes that it will take until 2050 for the ozone layer to return to “relatively healthy 1980s conditions” (2075 around Antarctica).
Flickr photo credit: NASA Goddard Space Flight Center