Will the Hole in the Ozone Layer Close?

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Hello, lovely, curious-minded people.

Welcome to the podcast of BBC Inside Science, first broadcast on the 15th of May, 2025.

I'm Victoria Gill.

Water, air, and earth are all coming under the Inside Science microscope today because, towels at the ready, water lovers, it's the start of bathing season, which sounds wonderfully Victorian.

But what is the science behind working out where it is safe to swim?

And we'll be finding out why some flowers might actually harm our urban bees.

We also have science and technology broadcaster and loyal friend of Inside Science, Gareth Mitchell, in the studio to take us through some of the scientific news shaping our world this week.

What do you have for us, Gareth?

Oh, it's lovely to be back.

I like the loyal friend better as well.

Thank you.

It's made my day.

So yeah, we're looking at why chimps' language, like chimpanzees' language, is more sophisticated than we previously thought.

We're looking under the bonnet of these AI chatbots, you know, like your Chat GPT or Google Gemini and so on, really to try and work out what is going on in these chatbots and what might it ultimately tell us about brain science in people, in humanoids.

I think I'll have a lot to learn from that one.

It's a fascinating story, peering really behind the scenes of these bots.

And another kind of bot from chatbots to robots, in this case, inspired by octopuses.

Oh, okay.

Sounds all sounds very intriguing and eclectic.

Well, if you will loyally wait and sit in the studio, we will be back with you shortly, Gareth.

Thank you so much.

First, though, I want to take you back to 1985.

There's new concern about the ozone layer, which protects the Earth from the sun's harmful ultraviolet radiation.

Some scientists say that more must be done to curb the use of the chemicals which cause its deterioration.

We were the first first three people to walk underneath this hole in the ozone layer that everybody's talking about around the world.

Us three are the only people that have ever subjected any flesh to see what happens.

And our flesh burnt.

It took months for the skin to stop peeling off our faces after returning back to civilization.

That was explorer Robert Swan.

And it's 40 years this month since a scientific paper was published that shook the world, revealing a a hole in the ozone layer over Antarctica.

It was a young British Antarctic survey scientist, Jonathan Shanklin, who examined data from an instrument called a spectrophotometer that measured the amount of the sun's ultraviolet radiation reaching the Earth.

Logging decades of that UV data, Shanklin revealed that the ozone layer over the research station in Antarctica was thinning and rapidly.

The reason?

CFCs or chlorofluorocarbons.

They were used as refrigerants and in aerosol cans.

They were also chemically dismantling the ozone layer that protects our planet from the sun's most harmful rays.

At a global meeting just two years later in 1987, every country agreed to phase out that group of ozone-depleting chemicals.

It was known as the Montreal Protocol, and it's considered to be the most successful environmental treaty in history.

Now, four decades later, we have the best evidence yet that that hole in the ozone layer is shrinking.

So, in 2025, what lessons can we learn about coming together as as a world to tackle and fix a global environmental crisis?

Joining me now is Professor of Atmospheric Chemistry and Air Quality at University College London, Eloise Murray.

Hi, Eloise.

Hi.

Welcome back to Inside Science.

Lovely to have you.

Remind us, the ozone layer, very important.

Why?

The ozone layer is this protective shield that's preventing us from being impacted by harmful UV radiation from the sun.

It's essentially contributing to making Earth habitable.

So the way that scientists and politicians really very rapidly came together to tackle the cause of it being depleted has always been lauded as a good news story.

Now, how significant was the Montreal Protocol?

It's incredibly significant.

And not only was it scientists and policymakers, but also innovators and industry found alternatives,

less harmful compounds that we would be able to implement quite quickly.

And it's significant because these compounds stay in the atmosphere for many, many, many years.

And so it takes a really long time for the ozone layer to repair itself.

So we needed to act fast to start the repair process.

And we're seeing it gradually improve, but we probably won't see an intact ozone layer for many, many more years.

There are new threats now to the ozone layer, aren't there?

That I know that part of your research.

What now are we seeing that chemically threatens the ozone layer as far as atmospheric pollutants?

One of the major concerns that we have is really coming from the space sector.

We have rockets that launch and in this launch process burn propellants, and these propellants release chemicals into the stratospheric layer of the atmosphere where the ozone is located.

We also have re-entry of space junk, and when that space junk re-enters, it burns up in the atmosphere and releases chemicals that are harmful to the ozone layer.

What makes this different is that these chemicals don't have to work as hard to get from the surface of the Earth to the ozone layer.

These activities are injecting it very, very close or directly into the ozone layer.

In terms of the pollutants from the space industry, it's about where those rockets are releasing those pollutants.

Yeah, being released straight into the stratosphere where they either react directly to essentially react away ozone or they're providing a surface for these reactions to take place faster.

Do we know how much of a disruption to that healing process these new threats are?

We're able to calculate roughly how much of a contribution they're making with the kinds of models that allow us to simulate the chemistry of the atmosphere.

And so with those models, we've estimated that they're probably making a very, very small contribution to ozone depletion, especially in comparison to the ozone depleting substances that the module protocol is regulating.

So, probably about a fifth at most of the sort of degradation of ozone in comparison to those ozone-depleting substances.

So, small currently, but I think something that's making us very concerned is that there's a lot of speculation about very, very fast growth of rocket launches and re-entry of space junk.

When we look at the Montreal Protocol and just how swift and collective that action was, what do you think we can learn now about, you know, in 2025, as we're looking at another environmental crisis of climate change, you know, more complex, but we know the science well.

What do you think we can learn about what happened in 1985 and 1987 that will help us to tackle this environmental crisis?

The science is mature.

We know exactly what happens in terms of chemistry and the stratosphere.

So that's really helpful.

It allows us to make quite accurate predictions about what the future might hold if we grow the space sector.

I think something that is quite complex and less based on science, but more based on regulation and policy is that we don't have propellants to replace the current propellants that we're using that would be cleaner and produce less pollution.

And we also have to figure out how to clean up clean up space.

And the only way that we clean up space currently is by returning junk to Earth and in that process producing pollutant.

So it's a different kind of problem where I think it's going to be very challenging to decide how to regulate.

And in talking about that regulation, do you think policymakers are listening this time?

Yes, there's definitely communities, agencies, potential regulating entities that are listening.

European Space Agency and the UN are talking about and trying to figure out this issue and bringing in experts like myself to inform them of what we know about the science.

Well Eloise Marie it's fascinating to talk to you as always.

Thank you very much for joining me on Inside Science.

Thank you.

Great to be on your show.

Gareth, it feels almost sort of whimsical thinking back of the Montreal Protocol and just such swift action in response to a scientific finding.

How do you reflect on that having covered climate change?

I mean it was phenomenal yeah because I've covered climate change in the years since and I am ancient enough to remember being around as the Montreal Protocol was happening, and we were all told to stop using CFCs.

You know, I remember as a teenager just looking at the deodorant can I was using to make sure we didn't have CFCs in it.

And it's been a complete triumph.

And I suppose, if anything's going to keep me awake at night worrying about this issue, is when we see in global trade the retreat from internationalism, and we know all about the tariffs and barriers to trade and so on.

Let us hope and pray that doesn't spill over into science.

Thank you, Gareth.

Now, seasoned wild swimmers will tell you that the sea is still pretty chilly at this time of year, but today, the 15th of May, traditionally marks the beginning of the bathing season in England and Wales.

It's a little bit later in Scotland and Northern Ireland.

But until September, designated bathing waters on beaches and in some lakes and rivers are regularly monitored for pollution, and they're ranked from poor to excellent.

So, to swim or not to swim?

Joining me now to break down exactly what those rankings mean scientifically is Roger Pickup, Professor of Environmental Microbiology and Health at Lancaster University.

Hello, Roger.

Hello.

Can I start by asking you, why do we only test in the summer?

Is there really a bathing season?

It sounds terribly old-fashioned to me.

I think it just fits historically when holiday season starts.

And also, it was, I think, basically designed for bathing beaches

at the seaside, but it's now progressed onto inland waters as well, where people use the waters for recreational purposes.

That testing,

how often are samples collected?

What are they tested for?

Yeah, they're tested on a regular basis, usually, I think, once a week.

But what they're trying to do is give a gauge of what was called the fecal pollution of the water.

Lovely.

Now,

you think a lake is quite clean, but it's receiving water from many, many places.

One of them, if you take Windermere, for example, takes water from treated sewage and quite often also untreated sewage, but it also has streams coming into it at various points.

And the whole catchment, the whole area which drains the rainwater, has animals on it and they defecate on the land and

the bacteria from their guts, which are called fecal bacteria, flow into the rivers and into the lakes.

And these are the ones which cause stomach upsets.

With poor, sufficient, good and excellent, what do they mean in terms of how clean and the amount of bacteria that's in that water?

If you take drinking water, we don't want any E.

coli in drinking water at all.

That would fail.

But for excellent, you can have some E.

coli in the water because it's impossible to find environmental waters totally free of it.

So it's based on a risk basis.

So when it's classed as excellent, they would not expect people to come down with diarrheal illnesses and other things.

If you get a run of poor, then you just don't go in the water.

If there's a run of excellent, then it's probably relatively safe to swim.

But it's not risk-free.

There will be viruses there and other pathogens as well.

And Roger, I understand that you're doing your own kind of experimental testing in Windermere.

What research are you carrying out there?

We got 100 citizen scientists.

We gave them the equipment and they went and took a water sample between

10 and 12 o'clock on a particular Sunday.

These Sundays were in each of the four seasons, and we've done it now six times.

They take a water sample, bring it back to our hubs.

We send some of the water off for chemical testing.

And so we're able to get get a kind of broader picture.

The majority of the time, most of the sites, 100 sites, they pass,

they're good to excellent.

Some fail, but on one particular sampling regime, we got a high number of failures, and that was after heavy, heavy rainfall.

So, you know, there might be sites

which would be cleaner and higher water quality in one lake than other sites in the same lake?

Yes, that's true.

Yeah, because nobody's ever done that.

Because the Environment Agency just take from three sites, we took from 100 sites on the same day, and we can kind of get a kind of contour map of quality.

And the quality was generally quite good.

But we did accept failures, and one of those failures was a leaking sewage pipe up near Ambleside.

And another failure was at the top end of the lake where there were some septic tanks which were discharging because they weren't being managed properly.

And we've heard a lot of pretty grim news about river pollution in particular over the last few years and that sewage discharges and that are associated with that heavy rainfall that you mentioned are happening more often.

Is the quality of bathing water getting worse?

There are certain groups who monitor these, more kind of citizen science groups as well, and they would say they are getting worse.

And given the information we get from the utilities that there are a lot of unregulated discharges, then it's not going to get better under those circumstances.

You live in the Lake District near Windermere.

Do you swim outdoors?

Yeah, we do, yeah.

As a scientist, do you look for particular cues in the landscape that would help you make an informed decision about where to choose to take a dip?

Straight after heavy rainfall, there'll be a lot of wash-off from the land.

So that's not a good time to go in.

Don't go in near where streams enter.

If you're in the river or even in the lakes, just avoid where sewage outlets are.

Roger Pickup, thank you very much for joining us.

It's fascinating to talk to you, and I hope you are going to manage to enjoy a little bit of outdoor swimming in this beautiful weather in the lakes.

Okay, thank you.

And I should say that if you want to find out more about the water quality in a designated bathing site near you, you can go to the government's SwimFo page if you just search for that online.

Gareth, are you an outdoor swimmer?

I not really, to be honest.

No.

I mean, I'd I'd be tempted because I know people who do a lot of cold water swimming and they seem to be very healthy and very happy.

Yeah, I'm a little bit of a wuss.

I won't swim in the cold winter months, but during the summer,

when the weather is like this, it's sparkling today, it is an absolute joy.

I would even go for a paddle.

I'll be keeping an eye on that data though.

I think the term fecal indicators will be sticking with me for a while.

Hey, this is Sarah.

Look, I'm standing out front of AMPM right now, and well, you're sweet and all, but I found something more fulfilling, even kind of cheesy, but I like it.

Sure, you met some of my dietary needs, but they've just got it all.

So farewell, oatmeal.

So long, you strange, soggy.

Break up with bland breakfast and taste AMPM's bacon, egg, and cheese biscuit, made with cage red, smoked bacon, and melty cheese on a buttery biscuit.

AMPM, too much good stuff.

You are listening to BBC Radio 4's Inside Science with me, Victoria Gill.

And it's probably not news to regular listeners that wild bees in Britain and across Europe are in decline.

You might even have planted native pollinator-friendly plants to give them a much-needed boost.

But research from Cambridge University has now revealed that not all soils are equal when it comes to helping our bees in towns and cities.

Dr.

Sarah Scott is a pollinator ecologist and toxicologist and has discovered something troubling in the nectar of flowers that are grown in the post-industrial city of Cleveland in the US.

Here's Sarah.

We're collecting nectar from a lot of these plant species that are really important to pollinators and we were looking for arsenic, cadmium, chromium and lead concentrations.

And we found not extremely high concentrations, but enough where we would start to see these sublethal effects on bees.

A lot of lead sources in these vacant lots come from the structures that used to stand there back in the 1980s before we banned lead in paint.

There was a lot of lead in paint that you'd find and so when these buildings are removed the paint dust from these buildings then are incorporated into the soils.

And let's see there's

cadmium and chromium are both byproducts of industrial and manufacturing.

And Cleveland has a long history of industrial activity in the area.

Right, so you find them in sites where there's been a lot of industry and older buildings that had this lead paint.

So

how long do they stay in the soil?

How long does this contamination last?

Unlike pesticides and other chemicals, heavy metals are just in the soil.

They don't degrade within our lifetime or within hundreds of years.

So it's a pretty persistent problem.

And any new source of metal contamination just builds upon all the history of metal contamination that's been there.

So it's kind of an issue that doesn't go away until we properly take action to fix it.

So do you know from your research why that's a problem for the bees and other pollinators?

They're sort of buzzing around feeding on this nectar.

Then what happens when they consume nectar that's contaminated?

There's There's been a lot of research with honeybees looking at the effect of metals.

And so there's obviously at super high concentrations, which is typically higher than you'd find in this nectar.

But at really high concentrations, we're seeing mortality with both adult and the brood.

But at these sublethal exposure levels, we're finding a lot of behavioral differences.

So lead, for example, has a negative effect on memory and learning, which for a a pollinator is really important because they need to be able to not only navigate to the resources but then remember how to get back to their nest.

We're also seeing differences in visit duration of the bees on the actual plants themselves.

Yeah, and I suppose it may be a very simplistic point, but pollinators with their little bodies, a small dose of this heavy metal contaminated nectar, it could be a big issue.

Yeah, even if it's low levels that they're exposed to in the environment, we can see it start to accumulate to levels where we see more of these effects on behavior and learning.

And what about honey where I live, which is quite a sort of post-industrial, kind of post-Victorian industrial meal town, and there's some local honey production, which, you know, I'll definitely kind of seek out my local honey.

Would there be an issue with that?

There seems to be some ability of honeybees specifically to filter the metals out of the nectar that they collect.

So the concentrations that we see in honey are much, much lower than what you'd expect.

I've got to admit, Sarah, when I saw this paper, I did think it made me a little bit sad because I kind of look, you know, when you think of sort of wildflowers growing on post-industrial landscapes, that seems like an area that was previously quite damaged, maybe quite sort of polluted, kind of coming back to life and nature getting a hold again.

Is there anything that can be done to figure out how these areas can be planted planted and made a little bit more wild and natural without this potential damage of contamination?

Yeah, one thing that I've wanted to make sure that's very clear is: I think having some flowers, even if they have some metals, is more important than having no flowers at all.

And so, really, still pushing forward that it's better to still continue planting, but just maybe start paying attention more to the history of the lands or what other structures used to be in that area and testing the soil for metals to see what's in there.

Bees have enough stressors as it is.

We want to keep giving them as much of a fighting chance as we can by providing food and resources.

Thank you to pollinator ecologist Dr.

Sarah Scott there.

And Gareth is still here in the studio to bring us not just this week's science stories, but the science stories that all the scientists are talking about.

What do you have for us, Gareth?

Oh, well, a load of stuff this week.

Language seems to be quite the order of the day.

And this comes down to the first of these examples, anyway, is chimpanzees and how it seems that their calls, their language, is a lot more sophisticated than we may have first thought.

And we think that might give us a little bit of an insight into how language evolved in humans as well.

And how do we know this?

What's been studied in chimp language?

Well, indeed, how do you study this stuff?

So this comes from some fascinating field work from the Thai chimpanzee project in Ivory Coast.

And a team out there monitored 53 wild chimps in all.

And one of the research institutions involved is the Institute of Cognitive Sciences, the CNRS, in Lyon in France.

And they very kindly sent me a little bit of audio.

So this will give you a taster, very evocative, of what they were listening out for.

And so there, of course, there's lots of insects in the background, but you can hear those chimps.

That sounds quite conversational.

It is.

It's a bit chatty, and it's about to get even chattier.

Here we go.

That's lovely to listen to, but you know, what have the researchers found?

Is it, you know, is that a collection of random sounds, or can we call it language?

It might sound like it.

So they've been listening out.

I mean, that was a very busy soundscape, so they've been focusing on more kind of individual calls.

And things like towards the end, when it got chatty, now my chimp language is not very fluent.

I've not been on the Duolingo, so I'm very much a beginner.

But I think what we heard towards the end of that clip when it got chattier was a sound that the researchers referred to as being a pant, that kind of growly, kind of, I'm not going to try doing it kind of sound.

I was really hoping you were going to do some chimp impressions there.

It got so close, it's about to be one.

And the pant sound, which I think that was, is associated with play.

It's a sound they'll emit when play is involved.

Then there's another sound that they do, and they have other clips that they picked up of this this called a who.

I mean, that's literally the name the scientists give to it, a who, which is a kind of who

kind of sound.

That's about as chimp as I'm going to get.

Very illustrative.

Very helpful.

Thank you very much.

And the who sound is associated with rest.

But when those two sounds come together, and this really gets the important part of the research, then you get a whole other meaning, which the scientists think is to do with nesting.

So it's a sound that the chimps emit when they are nesting.

They already knew that individual calls can be associated with individual things.

But this is the first time that they've heard one call, if you like, qualifying another, a bit like we do in our language.

So could you call that syntax, like the combination and order of sounds or words changing meaning?

Exactly.

So in human language, you know, we have syntax, we have the rules of grammar that determine how we construct sentences and therefore convey meaning and culture.

So I could say dog, you know, so if we were chimps, that would just be one kind of call.

But then, of course, we'll in our language use a word like an adjective to describe that dog.

So, we're using like a two-word combination.

We've tended to think that it's just humans who are compounding words in that way.

And yet, this research shows that this two-call structure seems to be happening in chimps.

And what makes it exciting is just the discovery in itself, but also how it suggests that the origins of our complex language may go to the common ancestor that humans share with great apes.

Moving on from chimps now, although sticking with language.

What else have you got for us?

Yeah, sticking with language.

So, this is a really fascinating insight into what's going on under the bonnet with these AI chatbots that we use.

You know, things like Chat GPT or Google Gemini, for instance.

And when we use these chatbots, I don't know, they certainly when I do, I feel as if they're almost a bit magic in a way.

You know, so you can just type in a prompt like, hey, can you summarize this conference i've been to for a linkedin post or something like that and it just does it these um researchers that i've been speaking to and hearing about are very interested in what is going on under the bonnet and so what they've done is taken a whole load of these models so not just kind of one or two but i think it's about 10 of them and importantly these are what they call open source models in other words they're ones where you can get into the source code you can actually see their inner workings and sort of dismantle them and figure out what it gets how they work Exactly.

So you can get into them.

What this research team are doing is almost like using computer applications that act a bit like an MRI scanner to analyze the so-called neural network, you know, the brain-like computing structure that underlies these chatbots.

So they said, let's see which bits light up when we do something related to language.

And I personally might have expected a whole load of little lights to come on when they do this, because these things are called large language models after all you'd think all of these little kind of elements of the neural network are going crazy but it turns out only about one percent of them are the scientists thought aha well let's see what happens if we deactivate these they call it ablation which sounds very sci-fi so they they ablate these the the bits that had been lighting up just to see what they do and sure enough the models really they they carry on working but they just spit out a whole load of gobbledygook they can't construct language exactly they lose their ability to construct and to process language.

So in other words, the scientists are saying, bingo, we have found these bits that light up.

And then the really good bit is it turns out that the corresponding elements of human brains that light up related to language and other functions like reasoning seem to be to about the same proportion and in roughly similar structures.

And so what these scientists are hoping and what they suspect is if that is the case, then we can do some really interesting and important science relating to human brain conditions, like dyslexia, for instance.

We can do that in these neural networks, these chat GPT models, as maybe a kind of proxy for what we might do in real human beings, you know, just as a starting point for research into all kinds of neuroscience.

Robot octopuses?

Yes, I can't leave without telling you about robot octopuses.

So, this is researchers in Bristol and China, and they develop robots with kind of silicone suction caps that mimic the suckers and octopuses.

They're mimicking the way that octopuses distribute their intelligence.

So an octopus, like, you know, for instance, you and I, we have one big centralized brain that does everything.

But octopuses do have a centralized brain that does kind of higher order processing.

But then it kind of delegates lower order processing to these little arms with the little suckers and so on.

So the suckers, as well as being used to kind of pick things up and to handle objects or whatever they, you know, prey or whatever they come across and octopuses, they also use their suckers to sense the environment and they're mimicking that in these what they call soft robots.

Right.

They think it could lead to some really good soft robotic solutions for industrial processes, for instance.

That judgment about how much pressure to apply and how to manipulate something that might be very fragile.

Exactly.

So like in these studies they've shown that it can pick an egg up for instance.

Or even I think even a bit of jelly.

I think it just picked up a bit of a wobbly bit of of jelly without dropping it,

which would be a tough thing for a hard robot to do.

Well, Gareth, it has been an absolute joy to have you on Inside Science.

Thank you.

Please do come back and bring us more stories.

Will do.

But that is all we have time for this week.

You have been listening to BBC Inside Science with me, Victoria Gill.

The producers were Jonathan Blackwell, Dan Welsh, and Claire Salisbury.

Technical production was by Searle Whitney and Nathaniel Danter.

The show was made in Cardiff by BBC Wales and West.

And I'll be back with you next Thursday.

But until then, thanks for listening and bye-bye.

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