Low Temperatures Enhance Ozone Degradation Above the Arctic

The mechanisms leading to the first ozone hole reported above the North Pole was studied by scientists of the KIT Instituted of Technology and Climate Research (IMK) after extremely cold temperatures, observed over the winter months of the 2010-2011 season, caused the most massive destruction of the ozone layer in the Artic to date. Based off the data collected, greater cooling of the ozone layer may enhance the effects of ozone depleting substances i.e. chlorocarbons. If repeated occurrences of these frigid weather conditions ensue, an ozone hole above the Arctic is expected to form.

It was nearly a year ago when IMK scientists and Oxford colleagues discovered ozone degradation over the Arctic that was nearly equivalent to the ozone hole over the South Pole. After studying the mechanisms of this observed phenomenon and publishing their findings in “Geophysical Research Letters”, it was noted that the Arctic hole was due to extremely cold temperatures in the ozone layer, located 18 km in the stratosphere. It is at this location where chlorine compounds, which exists from chlorofluorocarbons (CFCs), and other pollutants are chemically converted to attack and destroy part of the ozone layer at temperatures below -78°C. If these cold temperatures in the stratosphere ensue, repeated occurrences of an Arctic hole will continue to be observed.

The chemical composition of the stratosphere was analyzed and measured by the MIPAS satellite instrument produced by KIT scientists. Model calculations were also done to predict and determine “concrete” effects of further cooling. Based off the proposed model, it is said that “further decrease in temperature by as little as 1°C would be sufficient enough to nearly destroy all of the Arctic ozone layer in most areas”, according to main researcher Dr. Bjorn-Martin Sinnhuber. Research done on the Arctic stratosphere over the past 30 years has suggested that the frigid Arctic winters have been cooling down at a rate of 1°C, on average, per decade. According to Shinnhuber, climate change will be the primary contributor to the development/destruction of the observed ozone layer. With increased carbon emission and other green house gasses, the bottom air layers near the ground will warm up due to thermal radiation, which as a result will also cool the air layers of the stratosphere above.

Since the discovery of CFCs, which are attributed to the Antarctic ozone layer, research has suggested that these substances are difficult to get rid of from our atmosphere. It may take decades before these chemical compounds are completely removed from the air. With the threat of future cooling, these substances become the primary threat to ozone depletion, yet little can be done to rid them from our atmosphere. Though it is impossible to accurately or predict with certainty that temperatures will be low enough over a long period of time to comparably degrade ozone this winter or in the future, it is something we must constantly keep an eye out for.

Relating this article to what we have previously mentioned in class, it becomes obvious that our overshoot and overconsumption of fossil fuels is significantly impacting society as a whole. The atmosphere itself is taking a large hit from ozone depletion. Long-term effects can be seen in the geosphere, hydrosphere and biosphere as well. Further warming due to lack of ozone protection can cause glacial melting, evident from current events previously talked about. This glacial melt can cause increased water levels i.e. hydrosphere, and as a result, continental boundaries may see recession affecting the habitat or homes of humans and animals alike i.e. geosphere and biosphere.

March 2011: Strongly reduced ozone values (left, dark blue) and significantly increased concentration of chlorine monoxide (right, red) that is directly involved in ozone degradation. (Credit: IMK-ASF, KIT)

Image credit - http://www.sciencedaily.com/releases/2012/01/120119133759.htm

Source - Helmholtz Association of German Research Centres (2012, January 19). Low temperatures enhance ozone degradation above the Arctic.ScienceDaily. Retrieved February 14, 2012, from http://www.sciencedaily.com­/releases/2012/01/120119133759.htm.