Guests: Jonathan Shanklin | Meteorologist | British Antarctic Survey,
Dr. Paul Newman | Chief Scientist for Atmospheres | NASA,
Tina Birmpili | Former Executive Secretary | Ozone Secretariat,
Dr. Anita Ganesan | Associate Professor of Atmospheric Chemistry | University of Bristol
Category: 💬 Opinion | Ozone Hole
Podcast’s Essential Bites:
[3:30] JS: "In the air that we breathe, we have oxygen gas, and it's what sustains life on the surface of the earth. [High in the atmosphere, ultraviolet light can make oxygen react and form another gas called ozone, which] provides a protective shield to break off the very harmful ultraviolet light from reaching the surface. And so if we get too much ultraviolet light reaching the surface, then that can trigger skin cancers and it can trigger cataracts in the eye."
[6:17] PN: "In the late 1920s, a scientist named Thomas Midgley figured out that you could use CFCs as a carrier gas for air conditioning and refrigeration. And in particular he was trying to produce a refrigerant for car air conditioners. So the CFCs turned out to be very, very useful [but it harmed ozone]."
[8:42] KL: "In 1985 [the British researchers] had the data and a theory [of a shrinking ozone layer above Antarctica] and got it published in the prestigious journal Nature."
[9:55] JS: "The scientists went to [...] the Prime Minister [...] and the really convenient thing was that Margaret Thatcher had trained as a chemist herself. So she could understand the scientific theory behind the discovery, and was well placed to make sure something was done."
[11:51] KL: "In 1987 an international agreement called the Montreal Protocol set deadlines to end CFC production and consumption. Eventually, every UN member state would sign up. The first treaty to ever achieve this."
[12:04] TB: "I think [the Montreal Protocol ] is one of the most successful environmental treaties that we have, possibly not only [...] in the environment sphere, but in other spheres as well. [...] It has universal ratification, so all countries are parties to this treaty. It has a very strong science and also funding mechanism that tries to reconcile the different needs that [...] the developing and the developed parties [have]."
[15:15] AG: "[After the Montreal Protocol,] the concentrations of these gasses started really rapidly declining in the atmosphere. [...] After about 2012, the rate of that decline actually started slowing down. [...] There's about a 50% decrease in that rate of decline. And that indicated that something had changed. [Investigators in China found the factories which were producing these illegal chemicals and shut them down and CFC levels in the atmosphere returned to their downward trend.]"
[17:01] AG: "What was really encouraging to see was how quickly change actually happened once the information was brought to light. It showed that there is a mechanism for making people responsible. [The same technology can be used to track greenhouse gasses.]"
[17:52] KL: "What many companies started replacing CFCs with were HFCs hydrofluorocarbons. These don't eat the ozone, but it turns out they do trap heat. They are in fact a greenhouse gas."
[19:49] NR: "The battle to add a greenhouse gas to the Montreal Protocol was [a win], when nations signed something called the Kigali Amendment. It's now being ratified and earlier this month President Biden sent it to Congress for approval."
[20:17] PN: "[The] ozone is in fact getting better. There's year to year fluctuations of the Antarctic ozone hole, but the positive thing about this is we know that the ozone hole would have been a few million square kilometers larger if CFCs had not been controlled. [...] Sometime in around the 2060s [or] 2070s we should see the Antarctic ozone hole back to the conditions we saw in 1980."