Thursday, September 23, 2010

Ozone Recovery

Adam Gibson


ENVS 1020

Recently, a secondary source article called “Ozone Layer is recovering, says UN” was found on TG Daily that was referring to a recent United Nations report regarding a peer reviewed primary source called “Scientific Assessment of Ozone Depletion: 2010.” While the article got all of its facts correct, there were several differences between the two.

TG Daily

One aspect that the primary and secondary source focused on was The Montreal Protocol on Substances that Deplete the Ozone Layer, and the difference was how much each of the sources talked about it. A very brief overview of The Montreal Protocol is that it was adopted in 1987 in order to prevent harmful ozone-depleting substances (ODSs) from reaching the ozone layer, by placing bans on numerous compounds that had been found in common household apparatus such as refrigerators and aerosols that had been widely used up until this time, and as a result, were depleting the atmosphere. While the secondary source only goes so far as saying that nearly 100 of these substances were banned, while the primary source goes into much detail regarding the success levels of banning these products.

According to the secondary source, it appears that for every substance that was banned in The Montreal Protocol has almost been completely depleted from the atmosphere. However, it is here that the primary source shows an alternate view. While many OSDs have dispersed exactly as predicted, there are still many more that take a very long time to disperse to an appreciable extent. In other words, it will take many more years before these ODSs are only in the atmosphere to a negligible extent. There’s also another very important point to remember; even though production on these ODSs has stopped, there are still stockpiles of some OSDs in the forms of old fridges, foams and other such products, especially in East Asia. It is because of this that the dispersal of one ODS called tropospheric chlorine was only approximately 66% as fast as predicted.

In addition to this, there are numerous compounds throughout this article that up until a couple of years ago, there have been no real changes in the concentrations of these compounds. However, with less and less of these certain ODSs being released into the atmosphere, it is leading to the beginnings of decreases to be found in the concentrations of these compounds.

According to both sources, the Montreal Protocol is helping to control the levels of Carbon Dioxide and other greenhouse gasses by the control over these ODSs. In fact, it is believed that thanks to the Montreal Protocol more than 10 gigatonnes. This is a value that was expressed in both the primary and secondary source not only for its size, but for the fact that this goal is five times larger than that of the Kyoto Protocol, which is a protocol designed specifically to deal with the reduction of greenhouse gases.

However, there was some not as positive information regarding an increase of concentration in some of these substances that wasn’t mentioned at all in the secondary article. Hydrochlorofluorocarbons (HCFCs) are increasing at a rate of 4.3% per year, which is faster than what has been observed in previous years.

In conclusion, the TG Daily article did a good job of presenting the basic arguments that were found in this primary source. While the results were not nearly as complete or as scientifically based as what they may have been, they did provide a direct link to the paper if a person was interested in reading up on this subject in more detail.


· PRIMARY SOURCE: WNO/UNEP “Scientific Assesment of Ozone Depletion: 2010.” Scientific Assesment Panel of the Montreal Protocol on Substances That Deplete the Ozone Layer. September 16, 2010

· SECONDARY SOURCE (and picture) Ozone Layer is Recovering, says UN. Emma Woolacott (TG Daily). September 20, 2010

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