Study Indicates Low Temperatures Encourage Ozone Degradation in the Arctic
24.01.2012 - Atmosphere & Space, Arctic
According to research conducted by scientists from the Institute of Meteorology and Climate Research (IMK) at the Karlsruhe Institute of Technology (KIT) in Germany, unusually low temperatures in the stratosphere above the Arctic during the winter of 2010-2011 caused the largest destruction of the ozone layer above the Arctic ever witnessed so far. The researchers studied the mechanisms behind this depletion, and their findings have bene published in Geophysical Research Letters.
The team found that further cooling may enhance the effect substances such as chlorofluorocarbons might have in destroying ozone, as chlorine compounds and other pollutants are converted to substances which attack ozone at temperatures below -78°C.
They also inferred from this that occurrence of an ozone hole above the Arctic might become a more regular event if colder stratospheric temperatures continue. While the 1987 Montréal Protocol banned the use of ozone-depleting substances, it will take decades before these substances make their way out of the atmosphere.
Gathering data via satellites to measure the chemical composition of the atmosphere, the team of researchers used models to determine some specific effects further cooling of the stratosphere might have. Arctic winters have seen the stratosphere cool by about 1°C per decade. And while the lower atmosphere (troposphere) below becomes warmer as man-made greenhouse gasses build up, this will lead to a cooling of the stratosphere above it, as the heat is trapped closer to the planet’s surface.
IMK conducts a number of long-term studies on ozone. Researchers began an ozone measurement campaign in northern Sweden. It is too early to tell whether temperatures in the stratosphere will be low enough over a long enough period to degrade the ozone layer sufficiently this year.