Are our carbon sinks failing?

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You have downloaded BBC Inside Science first broadcast on the 17th of October 2024 with me, Marnie Chesterton.

Hello.

In the next half hour, does playing video games make you smarter?

And talking of smart, a psychologist wins the Nobel Prize in Physics.

What's shifting in science world?

And, Jacques Hughes, scientists find the culprit behind the second biggest mass extinction event.

But we start with some worrying noises emerging from climate science.

You don't need much of a science background to know that we take oxygen in and breathe out carbon dioxide, and plants do the reverse.

It's very useful if you're trying to get this greenhouse gas out of the atmosphere.

That's the deal.

But according to a team of international researchers, initial calculations from last year suggest that this deal might be off.

Earth's natural carbon sinks might be failing.

What does this mean and what is the fallout for the battle against the changing climate?

Joining me to discuss is climate scientist from University College London, Mark Maslin.

Hello.

Hello, how are you?

I'm fine.

Well, I'm slightly concerned, but we'll get into that.

First off, let's go back to basics.

What is a carbon sink?

So a carbon sink is any part of the Earth system, whether it's the oceans or the land, that absorbs carbon.

And you see this every spring.

So as soon as spring happens, plants burst into life and they suck out CO2 to build leaves, flowers, bark.

And that is the breathing of the planet.

And we've been very lucky.

Up to now, the biosphere has been taking half our pollution.

So every time we burn a ton of coal and we put a ton of CO2 in the atmosphere, half of it has been going into the oceans and to the land.

And the worrying thing is that seems to be stopping.

Okay, so why?

What is this new work telling us?

The worry has been with science that this wonderful sort of carbon absorption, which we've known about for decades, was going to slow down.

And what's happened is that even though quite a lot of the land was still absorbing carbon, we had two big, I would say, extreme climate events last year.

One was the wildfires in Canada, which burned a huge amount of forest, putting carbon back into the atmosphere.

And then we had the tragedy of the drought in Amazonia.

And that released so much carbon that it balanced out all of the other carbon that's been sucked out.

And this is what we're seeing.

We're seeing that extreme weather events are causing the biosphere not to be able to take up as much as it has been previously.

That feels huge.

The land didn't absorb any carbon last year.

It is huge because if you think about it we have been reliant on polluting the atmosphere and only taking half the consequences.

Now if the oceans and the land stop taking up that half, then of course we're going to be responsible for a lot more than half.

And the biggest problem is that there is a direct link between how much greenhouse gases are in the atmosphere and how much the planet warms.

So we still haven't reduced our emissions per year.

2023 was the most greenhouse gases we've ever put into the atmosphere.

And so therefore, if we can't count on having nature help us, it's going to mean that we're going to put even more greenhouse gases in the atmosphere.

It's going to accelerate climate change and all of the bad things that happen because of that.

And is this surprising?

Was this collapse predicted?

I wouldn't say it was surprising because that's why we've been monitoring it.

And so scientists have been concerned about this for decades, just wondering when it will happen.

And what we don't know is this just one bad year.

Are we going to have a recovery next year and perhaps the extreme weather events won't impact the land as much?

But we know in the future with warming oceans and droughts and heat waves really hitting the land, we are going to have less and less support from the natural environment unless we support it.

There is a lot of talk about tipping points in climate science.

Is this one?

I think this is not a tipping point because there are things we can do about it, but I think it is something that can accelerate climate change.

So we're concerned about where we are now with temperatures and what we don't want is to have it accelerate beyond what we can cope with.

And really what it means is we have to reduce carbon emissions as quickly as possible.

Tick.

That will then mean that less is required of nature to take up and we can also do things like reforest vast areas and rewild vast areas of the world.

Okay, so on that, if we're trying to get to net zero by 2050, a lot of the advice on what we need to do,

that relies on carbon sinks and models about how they work.

So is that going to change?

Are the models going to change?

So the models take in the fact that the carbon sinks will slowly reduce, but they also factor in that we can change them.

So what's a really odd thing is even though the population of the earth is increasing, it will stabilize about 10 billion people by 2050, which is an extra 2 billion people, they're all going to be living in mega cities.

So the world is becoming a wilder place, which allows us to reforest vast areas because since the beginning of agriculture we've cut down three trillion trees.

That's half the trees on the planet.

So there's huge rooms for us to actually reforest and rewild areas.

Therefore we can actually boost the natural immunity or the natural sort of carbon sink of the world and actually give us a little bit of breathing space as we decarbonise the whole of global economy.

Does the UK have any plans to increase our sink capabilities?

So, the really interesting thing about the UK is we have been increasing the forest cover of the UK since post-the First World War.

Because we had almost in England, particularly got down to zero forests because we've cut down trees to actually build ships to keep the French out during the Napoleonic Wars.

Then, we cut down trees to make trenches in France, and so therefore, it became a war effort for us to build up forests.

So we've done very well.

We've gone from zero in England to about 13% forest cover but we can do a lot better.

We could reforest a huge area of Scotland.

The only problem there is that a lot of the land or most of the land is in private ownership and it's trying to convince those owners that they need to reforest and repurpose their land.

Okay, and we've been talking about land sinks.

Is there any role that the oceans can take?

Oh, absolutely.

And this is the other concern that scientists have because one, the oceans are warming up.

And the problem with warmer oceans is warmer water can hold less dissolved gases.

So therefore, the amount of oxygen and carbon dioxide that is dissolved in the ocean is going to be reduced.

That means there's a smaller store.

But also, because of these real hot temperatures we've been seeing in the surface of the ocean, life is starting to suffer.

And therefore, the biology that's taking up carbon dioxide in the oceans is also starting to suffer.

We haven't seen the same collapse as we've seen last year on land, but again, we're monitoring it and that is another worry.

Look, Mark, we're coming up to another COP conference and the governments are all going to be there from around the world and governments have goals.

Does this work about landsink make a difference to the urgency of reaching those goals?

So the urgency of trying to deal with climate change has never been higher.

We've had the warmest year on record in 2023.

We've broken the 1.5 degree target that was set in Paris in 2015 over the last 12 months.

And then on top of this, we have all the extreme weather events in the last 12 months and now we see that the land carbon sink is not helping us.

We have been telling policymakers how urgent it is for the last 10 years.

And I think we now need to actually move into more like a war-like footing to actually deal with probably the greatest threat that humanity has ever had to face.

Mark Maslin, Professor of Earth Systems Science at University College London, thank you.

Absolute pleasure.

Thank you for having me.

Last week, the Nobel Committee handed out their annual prizes.

The award for physics has raised a few eyebrows.

Cosmologist Andrew Ponson has been having a look at the forces behind this seemingly odd choice.

Last week, the Nobel Committee stirred a bit of controversy by awarding their 2024 Physics Prize to researchers not in something solid and physics-y, like black holes or quantum particles, but in AI, artificial intelligence, the thing that powers your favourite chatbot.

Of the prize winners, John Hopfield at least started out in physics, but Jeffrey Hinton, cheekily, has no professional physics training at all.

He is, whisper it quietly, a computer computer scientist with a background in, even more quietly, psychology.

Let me tell you, some of the physics WhatsApp groups were not entirely happy.

So what were the Nobel Committee thinking?

To get inside their heads, we first need to understand how this prize is related to physics at all.

The winning work on intelligence is inspired by something called statistical physics, which is all about two contrasting views of physical reality, bottom-up or top-down.

Bottom-up means looking at things in terms of their smallest components.

Top-down means looking at things in terms of overall behaviour.

So in physics, say you want to know how a car engine is powered.

Top-down, you might talk about the way burning fuel puts pressure on pistons, turning the engine shaft.

All very well, but there's a lot of detail missing.

The bottom-up view is about that detail, like the tiny molecules of gas inside the engine cylinders, which can move, vibrate, spin, collide, react with each other and so on.

That's important but overwhelming.

We're talking about upwards of 10,000 billion billion molecules each doing its own thing so it's not possible to grasp this bottom-up view in totality.

One just cannot see the forest for the trees.

But the key technique, statistical physics, combines the best of top-down and bottom-up reasoning.

It uses the maths of probability to show how how averages over bottom-up details generate top-down things that matter.

Pressure on engine pistons, for example, is an average view of the jostling of tiny molecules.

It's not just engines.

Modern statistical physics helps design things like batteries, medical scanners, biodegradable plastics, actually anything where little effects combine to make big outcomes.

When it comes to intelligence, real human intelligence, that is, bottom-up, it comes from the near hundred billion neurons in the brain.

Learning occurs when the tiny individual neurons change their relationship to each other, electrically rewiring themselves.

Imagine you have two light switches, but every evening you switch both lights on simultaneously.

If those switches were neurons, over the weeks and months they'd gradually wire themselves together, and after a while, you'd only need to press one switch to get both lights on.

They'd have learned what you want.

The Nobel winning work dates back to the 1980s, when the winners used the powerful techniques of statistical physics to show how combining these individual neurons in sufficiently vast numbers leads to learning and reproducing patterns of almost limitless complexity, a major part of human intelligence.

That became the basis for mimicking it in a computer, for creating artificial intelligence.

So, modern modern AI can trace its roots not just to biology and psychology, but genuinely also to physics.

As you might expect, AI is now widely applied to all sorts of aspects of science.

A day after the Physics Nobel was announced, the Chemistry Nobel went to a team who used AI to aid them in predicting the behavior of proteins, the complex molecules that enable life.

One of the recipients is Demis Hassabis, who started out, don't tell anyone, as a video game designer.

I'm not on the right WhatsApp groups to find out how the chemists feel about that, but I think we can at least now decode the Nobel Committee's messages.

One, AI is here to stay.

Two, physics helps explain more than just the outer reaches of space or inner world of atoms.

And finally, three,

perhaps also that what you need to succeed in science is changing fast.

Thank you, Professor Andrew Ponson from University College London.

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Around 445 million years ago was a tricky time to be alive on this planet.

It was an important milestone in the Earth's history, the first mass extinction event.

This is before land vertebrates, but it still managed to eliminate 85% of marine species.

We've known for some time that this happened.

What we don't know is why.

There have been many theories, and this week, scientists at Leicester University published strong evidence in support of one of them: that the whole thing can be traced back to an asteroid collision somewhere between Mars and Jupiter.

Before going into the details of the study, I asked Chrisa Aftolidu, one of its authors, to take me back about half a billion years.

So, 450 million years ago is not that far away compared to the age of our solar system.

If you say so.

What I can say is that you can imagine our solar system with the planets as you see them now.

We had the eight planets, we had the main belt full of asteroids, and more or less everything is as you see it now.

It might be good to define our terms here.

We've got asteroids, meteoroids, and micrometeorites.

What's the difference between them?

Asteroids is any small body up there that's larger than one meter in diameter.

Then anything smaller is a meteoroid,

and anything smaller than a centimeter is a micrometeoroid.

Now, when the meteoroids enter the atmosphere of the Earth, for example, they make this beautiful light, you know, transient phenomena.

The meteors, the shooting stars, that we can see them several times in the year.

And when we collect them now from the ground, some of them make their way to the ground.

These are called meteorites.

466 million years ago, actually before then, a few million years before then, something massive smashed in our solar system and then triggered an ice age.

Is that what's happened?

450 million years ago, we had the formation of the asteroid family of Massalia.

So we have a very big remnant, which is the asteroid 20 Massalia itself, and then several smaller fragments, the asteroid daughters.

They start to move, and this led many objects at a small time scale to escape from the main belt, make their way to Earth and hit the Earth.

So imagine you have one asteroid at the beginning, the parent body of the Massalia family, and another asteroid collided with that

and generated thousands of smaller fragments.

And many of them, they escaped from the main belt, and then some of them managed to hit our our planet.

And this process could trigger that period on the Earth's evolution.

And when you say further studies, you've got all of these micrometeorites landed on Earth already, right?

That's correct, because nature is very generous with us.

It sent us a lot of material for free.

But our job is then to try to understand where is the source, right?

But we have a lot of material in our collections.

This brings us on to some of the sort of cross-referencing work, work, I guess.

You say you have to look through telescopes

and you look under a microscope

and you're looking for a kind of a similar recipe in the things far away and the things under the microscope.

Exactly as you said.

So we have the telescope, we observe a group of asteroids in the sky, let's say members of the same family.

The very first fundamental step is that do these things look alike?

Are they similar enough that we can establish a link between a family, an asteroid,

and a meteorite?

Don't forget that we really need to have families.

We need to have a breakup event in order to have meteorites, right?

And so far we have done this only with a handful of cases.

It sounds like what you're doing is some sort of reverse game of pinball, where the pinballs kind of break up as they hit each other.

And so you're trying to piece back what started all of this off.

Why are you interested?

Well, it's a very simple answer here.

By understanding the evolution of the solar system, we are a step closer to understand our existence, which is the holy grail, I think, in most of the sciences around.

And we try to do it with small steps by building these puzzles.

So we try to understand the materials, how they evolve in the solar system, orbits, the processes that they act act in the solar system, and one of those, a very severe one, are the impacts.

So, by putting materials, orbits, processes, all in our plate and try to combine the knowledge and fill in the gaps, we try to have a picture of the evolution of our solar system.

Because the solar system when it was formed, it was not what we see today.

The giant planets had different orbits, and because we want to understand where we live and why we are here.

here.

Thank you to Chris Aftelidu.

And finally, let's talk about your cognitive abilities.

That's how good you are at remembering and using knowledge.

If I asked you to pick which is better for your cognitive function, exercise or video games, you'd probably go exercise.

We're constantly told how good it is for you.

The World Health Organization even recommends it for cognitive benefits.

I'm pleased to say that joining me now is Professor Adrian Owen, Owen who's been looking at this topic and we've discussed this before on Inside Science so welcome back Adrian.

Thank you, thanks for having me back.

Now this is very pleasing because back at the start of 2024 we had you on Inside Science talking about a study you were about to launch and you wanted Inside Science listeners to take part.

What's the overview of the study?

What did you want listeners to do?

Well you know I have a bit of a reputation Marnie for trying to look closely at common neuroscientific myths to establish whether or not there's any basis of fact in them and this is an example of that.

I mean two of the most actively studied lifestyle factors that one could modify are exercise and video gaming.

And there's literature out there that suggests that both of these things, physical exercise and video gaming, can be good for cognition.

And by that I mean your memory, your problem solving, your ability to reason and your other cognitive operations.

A lot of studies only use young people, university students, they have very low power because they're a small number of people.

So we thought it was time to take another look at this, particularly since the World Health Organization has actually stated that regular, moderate to vigorous physical activity has beneficial effects for cognition.

So our overall aim was to look at whether the amount of physical exercise that people take and the amount of gaming, video gaming that people do, are related to cognitive function.

That's what you were looking at.

I took part.

I was one of your guinea pigs.

I don't know if you ended up using that.

But what was the headline result?

What have you found?

One of the results that people might find surprising because many people believe this is true, the amount of physical exercise people said they took

did not relate to their cognitive performance.

So people didn't have, people that exercised regularly didn't have better memories, they weren't better at solving problems.

I think that will be quite surprising for people, maybe even for the World Health Organization.

On the other hand, and this may also be surprising to people, playing video games did.

Playing video games is related to better memory, it was related to better reasoning, better problem solving.

Where I think things are very interesting is that physical exercise actually did have a significant effect on mental health.

That is, it was associated with lower levels of anxiety and depression.

So we've ended up with what we generally refer to as a double dissociation, that is that physical activity is good for your mental health, but has no effect on cognition.

Playing video games was the exact opposite.

It was good for your cognitive performance but actually had no effect on mental health.

Okay, so that's hugely surprising, I think.

You're saying actually there are benefits to exercise.

We do still need to do it, but it's improved mental health, not cognitive abilities, not your memory, your reasoning,

your attention span.

None of this suggests that we should be taking less physical exercise.

But what it does suggest, as you've said, is that taking physical exercise because you think it'll make you smarter, because you think it'll improve your memory, your general level of cognitive function, is not, at least based on these results, something that I think is worthwhile.

So if you can't improve your reasoning, your memory and your attention and your verbal abilities by either playing brain training games or by going to the gym more, is there anything you can do?

Well, let's look at our, you know, the video playing.

I mean, I think this is, again, a really interesting finding that, you know, people that play video games were better at reasoning.

They were better at problem solving and their memory was improved as well.

Now, just to be very clear about what we we did, because there's a huge amount of variability in how much gaming people did, we divided them up into people that

played no games at all, non-video gamers if you like, infrequent gamers, which is you do play but it's less than three hours per week, I'm in that category, and frequent video gamers who would play more than three hours a week.

So we had sort of three categories.

And it turned out that there was a difference both between non-gamers and infrequent gamers gamers and between infrequent gamers and frequent gamers, meaning that actually

even a little bit of gaming seems to have some beneficial effects.

Is that because most video games, whether you're playing Tetris or a shoot-'em-up or a FIFA football, is it because they're all problem-solving?

Yeah.

I think that's exactly the answer.

I think, you know, traditional brain training games typically just rely on practicing, remembering and these sorts of things.

Whereas, you know, modern video games, and I'm thinking of

the big strategy games, the big puzzle games like Minecraft and Civilization and these sorts of things,

these are puzzle-based.

They involve logic, they involve problem-solving.

I think what we're doing with these games is teaching people how to think.

Kate, one thing that I find particularly surprising, I mean, it is so odd, and I don't, I totally understand why the WHO guidelines are recommending physical activity, because,

you know, when you talk about it being good for your body, your brain is part of your body, so surely it would

boost blood levels into your brain, and wouldn't that have some sort of beneficial effect on aspects of cognition?

That is actually one of our explanations for why mental health increases.

I mean, increasing physical activity, of course, improves your cerebrovascular health, which increases blood flow to the brain, as you've said.

But it turns out that that effect is on your mental health, not on your cognitive health.

So whether it's to do with the

regions of the brain, the networks in the brain that are being particularly targeted by physical exercise, we don't know.

But you're not the only person who's going to be surprised by these results.

Well, Adrian, thank you so much for sharing this amazingly surprising results with us.

You're going to be at Manchester Science Festival on the 19th, aren't you?

I am.

In fact, I'll be there from from, I'll be there Friday, Saturday and Sunday and we have a whole exhibit that people can come by, they can try the games, they can do a bit of exercise, they can even do a bit of free video gaming.

So please, if you're in the Manchester area, do come on down.

It's going to be fantastic.

Thanks, Adrian Owen from Western University in Canada.

That's it from me.

Victoria Gill will bring you Inside Science next week.

Also Manchester based to explore the revolutionary potential of graphene on its 20th birthday.

Bye for now.

You've been listening to BBC Inside Science with me, Marnie Chesterton.

The producers were Sophie Ormiston, Ella Hubber, and Anna Charalambu.

Technical production was by Searle Whitney.

The show was made in Cardiff by BBC Wales and West in collaboration with the Open University.

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