ozone layer is healing (but pitfalls remain)

[everything]

https://www.unep.org/news-and-stories/s ... lls-remain

In 1987, the world came together to sign the Montreal Protocol, a global agreement to protect the Earth’s ozone layer. The accord was designed to phase out a host of chemicals, such as chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), that were creating a continent-sized hole in the ozone layer above Antarctica.

Today, the ozone layer is healing, shielding the planet from the potentially devastating effects of ultraviolet radiation.

But while it may have slipped from the headlines, the ozone layer still remains under pressure, said Meg Seki, Executive Secretary of the Ozone Secretariat under the United Nations Environment Programme.

“People tend to assume that the ozone hole is history, that we’ve done our job. Actually, we have a lot of challenges still ahead of us.”

In the lead up to the International Day for the Preservation of the Ozone Layer, which falls on 16 September, we spoke with Seki about the perils facing the Earth’s sun shield and whether the Montreal Protocol can be a template for fighting climate change.

The Montreal Protocol has been called one of the most successful global environmental agreements in history. Why?

Meg Seki (MS): The Montreal Protocol is so significant because it successfully tackled an emerging environmental catastrophe. When scientists alerted the world that there was a gaping hole in the ozone layer due to man-made chemicals emitted into the atmosphere, political and environmental leaders came together to address the problem. Today, more than 99 per cent of ozone-depleting substances have been phased out and the ozone layer is on a path to recovery.

What is the size of the hole in the ozone layer now compared to 1987?

MS: Because of the annual variability, the size of the hole goes up and down depending on the temperature in the stratosphere. So, we cannot predict this in advance but there’s a gradual but definite trend towards recovery.

How long until the hole is no more?

MS: Scientists estimate that the hole in the ozone layer will be no more by the 2060s. However, it’s very difficult to talk about complete recovery because the atmosphere itself is very different to what it was when there was no ozone depletion. Greenhouse gases, temperature changes and global warming all affect the dynamics and chemical processes in the atmosphere, impacting the recovery process. In other parts of the stratosphere, the ozone layer recovery is expected to be earlier.

Does climate change threaten to undo some of the progress we’ve made in repairing the ozone layer?

MS: This is a very complex issue. Ozone-depleting substances controlled by the Montreal Protocol are potent greenhouse gases that cause climate change, but we have managed to control and phase out their emissions. Climate change itself is causing changes in atmospheric circulation and temperature, which affect the depletion and recovery of the ozone layer.

[nicklinjm]

This is great news, shows countries can solve environmental issues if they can all pull together. Remember ozone and acid rain being front-page news when I was a kid!

[everything]

yeah I remember as well. the no hair spray kind of lessons people said (ah, back in the Big Hair 80s...).

definitely almost unbelievable (to this cynical person) that humans got something right like that... unfortunately gonna need a lot more successful coordination to keep fixing things