Satellite data show the Antarctic ozone hole as it appeared last fall.
(Image courtesy of NASA)
Back in the 1980s before climate change dominated our news, Ozone depletion was the main danger to the environment. The Ozone layer that protects us from the strong UV rays has been slowly recovering since 1987(Montreal Protocol banding CFCS). However every winter the Arctic ozone layer suffers a relapse and this year (2012) could be the worse, thanks ironically to climate change. Dr. Kaley Walker (Atmospheric Physics at U of T) belongs to a team of scientist who monitors the ozone over the Artic every winter. This week Walker’s team released a report that indicated that this winter might set an all time record for ozone loss.
To monitor the conditions of the ozone of the Artic Circle, Kaylee’s team conducts measurements using a satellite (Atmospheric Chemistry Experiment) from above. Other procedures are done during the springtime, including measurements taken by using balloon borne instruments and ground based instruments from a particular place in the Artic called Eureka (80 degrees north). Kaylee’s team is particularly interested in monitoring the Artic during times when the ozone depletion occurs, February and March, when the sun comes back.
At the moment the Artic has experienced a particularly cold winter, thus a large amount of Ozone depletion has occurred. If we compare the data of this year to the data collected during the late 70s and early 80s we are down by 40% less Ozone above the Artic this year. At the moment the season is not yet over, and the sun is reaching full exposure, as we are getting closer to the North Pole, which allows us to predict that a lot of activity will occur within the next weeks.
Why is Ozone depletion still occurring?
Chlorine (CFC) one of the largest contributing factors. Chlorofluorocarbons are the sources of Chlorine in the atmosphere, although we have banned CFCS during the Montreal Protocol and have seen some evidence that this has worked in decreasing the amount of Chlorine in the stratosphere, the area where the ozone layer is, but at this point it has not decreased to the levels it has been prior to when we started putting them there so it is going to take some time.
Process of Depletion
When the Arctic air over top of the Pole is isolated by wind patterns. The wind patterns are such that air stays over the Pole and doesn’t travel very far, this happens and we don’t get any sunlight, thus making it very cold. Within this cold and dark Artic air Polar Spherical clouds are formed. These clouds are filled with Chlorine, so when the sun comes back it evaporates the clouds and releases all of the Chlorine back into ozone. Thus, the colder it is the more clouds are formed causing more chlorine to be released and inevitably causes ozone depletion.
Understanding the greenhouse gasses and that warming is very important as well. CFCs are also a big contributor to greenhouse gasses, so by banning them we have averted a certain amount of warming that could have occurred, however the warming from increased CO2 and other chemicals still applies. Dr. Walker continues to do research on applied models to see how the warming from greenhouse gasses, and the cooling from depletion in the Arctic can be manipulated to balancing out the climate structure.
So how long will it take until this problem is gone?
Dr. Walker predicts that it may take till the year 2050 until the problem goes away, this prediction is “based on her models and having a certain knowledge of how the rest of the atmosphere is going to change. “