Guest Column with David Karoly - An important anniversary that almost passed unnoticed

October 10 / 47

Professor David Karoly is an ARC Federation Fellow in the School of Earth Sciences and leader of the Climate Change theme in the Melbourne Sustainable Society Institute.  He is an internationally recognised expert on climate variability and climate change, including greenhouse climate change and stratospheric ozone depletion.

We hear a lot in the media about the difficulties of implementing national and international policies to achieve sound environmental outcomes. The political debate about addressing climate change is just one example.

Hence, it is a little surprising that the anniversary of a remarkably successful international policy passed last month with almost no mention.

September 16 was International Day for the Protection of the Ozone Layer, marking the 23rd anniversary of the signing of the Montreal Protocol in 1987. This year also marks the 25th anniversary of the discovery of the Antarctic ozone hole by scientists from the British Antarctic Survey.

The ozone layer protects life on earth from some of the harmful effects of ultraviolet radiation from the Sun.  The Montreal Protocol is an international agreement designed to protect the ozone layer by initially limiting and then banning the production and use of many ozone-depleting chemicals, such as CFCs and halons.  It has been very successful in two quite different ways.

First, the concentrations of ozone-depleting chemicals in the atmosphere have peaked and started to fall. Although there are no clear signs yet that the ozone layer has started to recover, it has not become any thinner and the ozone hole has not worsened over the last five years. 

If all countries continue to honour their commitments under the Montreal Protocol, then the ozone layer should recover over the next 50 years and the Antarctic ozone hole will become a memory.

There is a second great success arising from the Montreal Protocol. Ozone-depleting chemicals are also very potent greenhouse gases. The reductions in their concentrations over what they would have been without the Montreal Protocol is substantial and has reduced global warming.

In fact, the reduction in greenhouse gases due to the Montreal Protocol is five times larger than the reduction in greenhouse gases achieved through the Kyoto Protocol. So there is already a successful international policy agreement that has reduced global warming, if only by a small amount.

Some people say that the Montreal Protocol was much easier to achieve and implement than an international agreement to fully address human-caused climate change, and they are correct. But we should celebrate our successes, even if they are small ones, and use them to show that international agreements on sound environmental policies are possible, but difficult to achieve.

Happy Anniversary!

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