If I’m awake to see the sun come up, it’s a great start to the day. I mean it's just clear blue sky...
- You feel more energetic, positive - You know the whole day’s gonna be pretty good.
I think my mood goes up, it doubles, you know. I’m Marnie Chesterton and you’re listening to
CrowdScience, the show that answers questions sent to us from all over the world and
sometimes, if we’re lucky, also takes us to some of those places – which is why I’m currently
enjoying some winter sunshine in southern Spain. I’m here to try and find out whether the weather
makes a difference to our mood, and our health because listener Michael in Australia
got in touch with this question: [Michael] I would like to know why so many people,
at the slightest sight of sunshine and warmth, have sharply increased enthusiasm for life
and their moods appear far happier. I'm wondering as to the science on whether
it's actually better health-wise, to live in a warm climate. [Marnie] I'd like you, Michael, to tell me a
bit more about the bit of Australia that you’re from? Because I always think of Australia
as hot and sunny, but you live in an anomaly? [Michael] I think the anomaly is the southern part.
Particularly where I'm from in Melbourne which is southern Victoria. We have an Oceanic climate which is not
much different to what you guys have in London. Of course, we have greater variation, with higher highs, but we also have a terribly gloomy climate,
by the standard of Australia and that's what's important to remember here Marnie,
this is not by the standard of, I don't know, Scandinavia or something like that. And the problem that we have here locally is the inconsistency. Summertime, or leading
into summertime, you might have a 25, 26, 27-degree day for three days in a row
and it will just tank to 16, 17. [Marnie] Can I ask what kind of effect
that has on the people in Melbourne? [Michael] What you have is that typical,
cold-climate dropped headedness and I also lived in Sweden, and I noticed
it absolutely everywhere in Sweden, and when the sunshine comes out,
there's a little bit of warmth behind it, the mood is better, everyone's at the café,
'Hey, mate! How you going? How's the day?' 'Yeah, great!' [Marnie] You're not just interested in mood, right?
You also want to know about whether living somewhere sunny has an effect
on other health conditions. Anything in particular? [Michael] No, not really. I'm interested in the science as to whether
it is actually factually better health-wise to base yourself in a warm climate or if it's in your mind, and therefore you have
a better existence because your mind is a little healthier because of it.
I'm not sure and I'd love you guys to answer that. [Marnie] Have you thought about moving? [Michael] Yeah, of course.
Yeah, absolutely. [Marnie] Is it common in Australia
for people to head to hotter parts? [Michael] Extremely. You get it a lot here,
with people with arthritis and other conditions like that where the doctors will say to you,
'Hey, you probably really should consider living in a warmer climate.' We have that option, granted, in this country. [Marnie] Admittedly, most people don’t
have that option, but for me, living in London with its winter gloom and
unpredictable summers, it does sound tempting. I’ve come to the little whitewashed village of
Chite, in a valley in Andalusia in Southern Spain. There are golden mountains
rising all around me, and orange trees and olive trees as far as the eye
can see… and, I’ve gotta say, it’s pretty idyllic. This part of Spain, where temperatures tend
to stay above 20 degrees Celsius in December, is home to loads of retired British
people - and they’re all convinced that the weather’s responsible for their excellent health. - My name’s Carol, I was diagnosed
with ME, and fybromialgia, and had a lot of joint pain and nerve pain. When
I came to live here, in Spain, the heat actually made me physically better as well as psychologically.
You want to go outside more, rather than in England you feel as if you want to stay
in the warmth of your home. - My name is Olywn and I’ve lived here for 19 years,
I think. When I was diagnosed with arthritis then it just seemed like a good idea and I talked
it over with the consultant and he thought it was a good idea,
so out we came. I don’t know if it’s just that you psychologically feel better about it
when the sun's shining or whether you really feel better…
but certainly not as achy - My name’s Tony Langham, and I’ve lived
here on and off for about 12 years. [Marnie] And you’ve got a heart condition, right?
[Tony] Yes, I had stents put in last year. It is easier to look after your heart
out here than it is in England, definitely. I mean the cold, for one thing,
can really get to you. [Marnie] Do you think the weather makes a difference
to your health? [Tony] Yeah, I think it certainly does,
psychologically probably, but as we’re body and mind together obviously if it’s making
one thing better, it’s making everything better. [Marnie] Tony, Olwyn and Carol all think
that living somewhere warmer and drier than the UK has eased their aches and pains. But what is it that’s helping? Is it the
warmth from the sunshine... or the extra light from a sky not blanketed in cloud?
Or is it that this sunny climate is making them feel positive, which changes their
mindsets about their health conditions? Or is the sun directly improving
their arthritis or angina? Well, if you’re familiar with our back
catalogue you’ll know CrowdScience has investigated the link between weather
and pain before… and we discovered that, while loads of people think there’s a
connection, the science has been under-researched. [Anna Beukenhorst] For centuries patients have said
that there is this link between weather conditions and their pain, but scientists
were never able to pinpoint it. [Marnie] Until fairly recently. That’s data scientist Anna Beukenhorst. She is
one of the authors of a study which analysed data from around 10,000 people across the UK to
try and get a clearer picture of what’s going on. Participants with a range of conditions used their
smartphones to report their daily levels of pain. Then the team cross-referenced that information
with the precise weather data in their location. [Anna] And we found that higher humidity,
lower air pressure and stronger winds were significantly associated with increased
pain. So in the worst possible combination, which would be a humid, windy day with
low pressure, painful days were 20% more likely. And interestingly, we didn't
find a link between temperature and pain, or between rain and pain. [Marnie] That's interesting, because low pressure weather tends to be stormy or
cloudy, and cloud means less sunshine, and yet there’s no statistically significant link
between pains levels and rain or temperature. In general, people were likely to
suffer just as much when it was hot. Which might sound surprising to people like
Carol and Olwyn and Tony who say they’re less achy – and more mobile – now they’ve
settled under the Spanish sun. But they did all mention the physical
and psychological aspects of waking up to sunshine and blue skies. So
could something else be going on? One option is that warm, nice,
weather may affect people's mood. Because we saw in our study, that people's
mood had a strong relationship with pain. And that was even stronger than
the link between weather and pain. Of course, you have a bit of a chicken and egg
question. So we actually couldn't determine what came first, the bad mood or a lot of
pain and I think if you suffer a lot of pain and all the daily living activities get much
harder yet and that may also affect your mood. [Marnie] OK. But there is a possibility that even if
you're suffering from chronic pain there’s some sort of positive mood benefit
from having lovely sunny weather and that may influence your pain levels?
[Anna] Yes, yes, I read one interesting article, where they sent people from Norway to Spain to
benefit from the climate. And I think during the whole study period, which maybe was one month or
so, they didn't see any differences. But the first couple of days, people were both happier and more
pain free than they were in their home location. [Marnie] Despite the lack of hard scientific evidence
that hotter weather is actually better for people suffering painful conditions, something
about putting folk out into the sunshine does seem to trick some people’s brains into
feeling less pain. Kind of like a warm placebo. Anna mentioned Norwegians who make winter trips to
Spain to benefit from the Mediterranean climate, they felt happier when they first arrived. If you’ve ever been to Norway, you’ll know it
gets very cold, and very dark in the winter. Some bits of the country see absolutely no
sunshine for months on end. And I’m intrigued…. - I’ve got one side of the bag that's got my sandals and short sleeved t-shirts and then the other
side is hats, gloves and thermals! …which is how I find myself
swapping the orange groves of Andalusia, for a small, snowy
town three hours west of Oslo... - Ooh, that is bracing!
...called Rjukan. - These guys do winter differently to
people in Southern Spain, clearly. We’ve just arrived in Rjukan and let me just say,
it’s a lot colder than it was in Spain, my fingers are freezing. That's partly because, for six months of the year,
the sun doesn’t reach the town at all. Until a few years ago, the only way people could catch any rays, was
to take a cable car to the top of one of the mountains overlooking the town.
I’m going to take a ride to the top and find out what a difference it makes
for people who live their life in the shadows. From the top of the cable car, you can
look down onto the long narrow streets, blanketed in blue shade at the bottom of
a valley formed by two walls of mountains. It does seem like a strange place to build
a town and yes, Rjukan is relatively young, founded in the early 1900s when an entrepreneur
realised that the long waterfall coming off one of those mountains could be tapped
for a hydroelectric power plant. And it was the hydroelectric
company that built the cable car so that its employees could travel to the
top and feel the sun on their faces. - If you go to the top of the station, to the
viewing point, you might reach the sun, maybe. - We're properly sun-chasing! You guys have come up here, can
I ask, do you live in Norway? - Yes, we live in Oslo.
- And you thought, what, 'I'll come to the valley with no sunshine,
just to feel better about how much sun there is in Oslo?!' - Yes that’s true, that's true.
I’ve always thought that, I mean of course, sunshine is something you need,
and you need that to survive and live, and the fact that people
actually live here without it, it's fascinating. [Marnie] Fascinating may be one way
to describe life in Rjukan, but for many people here
the winter is pretty hard. For a start, we use direct sunshine to make
vitamin D, which might play a role in regulating mood, and is well known to guard against many
conditions from colds to cardiovascular disease. Sunshine also plays a key
role in a mental illness - sometimes called Seasonal
Affective Disorder, or SAD. This form of winter depression happens when we
make too much of a hormone called melatonin, which has a production process regulated by
sunlight. Not enough light, and our body clocks are thrown off their regular rhythm, triggering
all sorts of symptoms, including a lack of energy… [Bjorn Birkeland] More need to sleep, reduced
movement, more appetite, especially sweets, weight gain, social withdrawal
and reduced sex drive. [Marnie] And according to town
psychologist Bjorn Birkeland, Rjukan has higher levels of SAD
than other parts of Norway: [Bjorn] The rest of Norway, we think it’s 5-10%, and
in Rjukan, we estimate it to 15 or 16%. [Marnie] Can you treat it?
[Bjorn] Yes. With sun and light. It’s the only method. [Marnie] So, he prescribes light therapy.
Which is what it sounds like, a big bright lamp to sit in front of for 30 minutes
every morning, to try and combat the problem. But even for people without SAD,
the option of travelling to the top of the mountain to see
sunshine didn't quite cut it. [Martin Andersen] I moved here in 2002. I knew the conditions but still it was very strange, because we moved in the autumn, just when the sun started to disappear.
[Marnie] Oh, brutal! So, how bad was it? [Martin] The first impression was quite bad. It was
more the idea that the sun is disappearing. Especially in the autumn-time, it's a
very big difference between being in the sun and being in the shadow because it pushes down the cold, somehow. And I mean the town, it never dries up. [Marnie] How did it make you feel? [Martin] I don't know... Desperate! But then I thought, why not
reflect it down to one place, and there will always be sun in this place if it’s a sunny day. And
then I went to the municipality and proposed the idea, I wrote the document. And then I found out it was an old idea,
from 1913 was the first time, and it's been repeated a lot of times. [Marnie] OK, so every generation, someone comes along and goes, ‘why don’t we do this?’ ...and then nothing happens?
[Martin] And nothing happens! That’s the difference between me and the others, I’m more stupid and
just never gave up and spent more time on it! [Marnie] Martin Andersen might call himself stupid, but
his proposal had a genius simplicity to it. I arrived in Rjukan on a
sunny day. By which I mean you could see the bright sunshine glinting off
the mountain tops. Well, Martin wanted to put some massive mirrors up there, and angle
them to reflect light down into the town. And, in 2013 - a hundred years after the Rjukan’s
founder had first suggested something similar - its now world famous ‘sun
mirrors’ were levered into place. [Martin] The mirrors are 51 square metres all together, coming
down you get 90% of being in the direct sunlight. It’s three mirrors going to the
same spot. It's on the main square in town. It increases and decreases during the day, but 300-600sq m [of sun] you get.
[Marnie] So, three mirrors, each about the size of a bus reflecting light down into the town square?
[Martin] Mmm. It becomes a very nice spot, It’s like a theatre light which comes
down… it is like being in the sun. [Marnie] At this point, you’re probably
wanting me to head to the town square, feel that sun on my face and talk to all
the locals I find there sunning themselves. But the town square in Rjukan
is looking empty and bleak... because this winter, all three of
Rjukan’s mirrors have broken down. To get the sunshine in the same spot as the sun’s
position changes, the mirrors have to undergo micro-adjustments to their angles. It’s all
co-ordinated by a computer system – and sadly, that connection crashed about a week before I arrived. But Martin takes me outside anyway, to look up at the mirrors and paint a
picture of life in the town when they worked. [Martin] Now you see them. You see two are flat?
[Marnie] Oh yes… is this whole square lit up by the mirrors? [Martin] No, no, not the whole... just in front.
[Marnie] So people gather here and just point their faces and say, 'burn me now'? [Martin] And a lot of tourists come here to just be in this spot.
It's very funny, you drag them into a dark valley just to see the sun. (laughs)
Reflected sun. [Marnie] But it’s special sun, exactly, because it’s reflected. I mean, is it the same sun? [Martin] No, it's just an image of the sun.
But it makes a very nice contrast to the rest of the place. I call it like a smiling machine, because
people, they come in, and then everybody smiles. [Marnie] Can you tell me how people are reacting
to not having their winter sunshine? [Martin] I hope they burn cars in the
street to get it back here! (laughs) [Marnie] How do you feel about not being
able to pull into this square and get some sun?
[Martin] I think it's very sad. It’s a big plus to have this
little spot of sunlight. When it’s not there, it becomes more gloomy than it should be. Rjukan is showing me how radically the
sun can alter our behaviour. The mirrors there act as a magnet for bringing
people together at the height of winter, even just for a few minutes. They also remind them
what’s round the corner – spring. The residents celebrate the return of the sunshine in
March with a massive fancy dress party. And that chimes with the research. While most of
the studies on mood and weather are inconclusive, the importance of seeing sunshine at certain
times of year is becoming better established. Oscar Ybarra is a professor of organisational
behaviour at the University of Illinois in the US. He was part of a team that discovered that
seasonal sunshine not only makes us happier, it can also help us to think more clearly. [Oscar Ybarra] Previous work had looked at simply associating,
whether it was temperature or pressure with how people were feeling. And our approach was
a little different. We thought there would be more nuance in that what might matter more is the
season, right? Because, after a while, if you're deep into the summer, another warm day is just not... it won't
have the same effect, as the first few warm days in the spring, for instance.
[Marnie] Ah nuance. Because we humans are complex. And Oscar’s team thought a sunny day in the
right context might have a strong effect. They designed a series of experiments to test
how much of an effect seasonal differences had on mood and cognition. And they
found two factors were important: [Oscar] The temperature and amount of sunlight have
to be, I won't say just right, but compared to what they've been, you know,
they have to be more agreeable. And then in addition to that, you have to be able to
spend time outside in that nice weather so, specifically what we found out is that as
the weather turned nicer, especially after a northern winter, and people got to spend time
out in that nicer weather, then what you saw was, that was associated with better moods, and also
with better memory performance. And in that one study where we also looked the degree to which
they updated their beliefs, nicer weather as well was associated with people's willingness to update
a prior belief that they had about an individual. [Marnie] So all sorts of bits how to do with how our
brains process information seems to change, it seems to be affected by a mixture of this sweet spot, of it's got to be the right temperature, it's got to be warmer than it had been…
is there anything else I'm missing? [Oscar] Yes, and you have to be able to be, you
know, outside in that nicer temperature. [Marnie] OK. Is there a minimum amount of outside
time that you need for this to work? [Oscar] Sort of the breaking point
between where you started seeing benefits versus no benefits was around 30
minutes… it's unclear whether depending on just exactly where you were in the season
whether it will be less time than that, or more. [Marnie] You mentioned seasons. Is there a time of year
when this sunshine and warmth makes a difference? [Oscar] What we showed in the studies is that it's
really coming out of the cold winter season, that you see these benefits, so, once you
start transitioning into the spring and summer, and that's related to this idea that there is
a sense of novelty associated with it, and what is it that, in a sense, represents the largest change
from where you’ve been. [Marnie] It makes sense. If you live somewhere
that’s sunny and 19 degrees all year round, you kind of get used to it, I suppose. It's not a treat any more.
[Oscar] Yes. Yes, it's not a treat anymore. And take it from somebody who grew up in a place that
had more than 300 days of sunshine every year! [Marnie] Whereabouts did you grow up?
[Oscar] I was born and raised in a little town called Alpine in West
Texas. So you asked me earlier what the weather was like, here in Urbana, I said it was cloudy.
Sometimes I don't mind the cloudy days, still! After this winter, I'm sure I will enjoy the nicer weather.
But you know, too much of something can become oppressive. [Marnie] So it really doesn’t need to be all that
hot for us to experience mood and cognitive benefits. We just need a shift from colder
to warmer – so a change of season, like spring, like they have in Norway. That reappearance
of the sun seems to be more important than how much heat it’s giving off. Which is lucky,
cos March in Rjukan is still pretty chilly. The sweet spot seems to be around 20 degrees
centigrade, and even that needs to not be a constant, because we quickly start
taking any weather pattern for granted. Of course, too much sunshine can also cause all sorts of other problems, like
skin cancer and heat stroke. And, as more parts of this planet hit 50+ degrees, it is worth looking at the negatives that sunshine
and heat can have on our health and well-being. Professor Solomon Hsiang is
Director of the Global Policy Lab at the University of California, Berkeley, and has
found evidence dating back 10,000 years that high temperatures can actually
be really harmful for how we humans behave. [Solomon Hsiang] We looked at studies that had been conducted around the world. And what we saw was a repeating pattern, where when the climate in the historical
record shifted to conditions that were not so favourable, you know, to people, not favourable
to agriculture, we saw higher rates of conflict, violence, or things you might call, you know,
the collapse of civilizations, even. So, there's lots of different examples,
whether you look at, you know, the Maya in Central America, or you look at Angkor Wat, in South-east Asia, which societies, you know, were faced with very long
droughts, or extremely cold conditions, if you're very far north for a long time,
or extremely hot conditions for a long time. And we see that that put a lot of stress on these
societies and to the point where in many cases, governments collapsed. And that
was really the end of those communities. [Marnie] I’m intrigued, how do you pinpoint the role of
climate in the collapse of an entire civilization? [Solomon] It's challenging to say that the climate was
the only reason why a society broke down. In many cases, what you see is a pattern
of overlapping stresses. So for example, in the case of Angkor Wat, you know, they
were at war with their neighbouring city for a long time. At the same time, they had
to support, you know, a growing population, and then they were faced with a multi-year drought
that they were trying to cope with and manage. And sometimes it just turns out to be too much.
And I think we see that over and over again, [Marnie] Can you link that to a change in temperature
in particular, or is it just if it's normally somewhere that's hot
and relatively arid, and suddenly there's a lot of rainfall, or vice versa? [Solomon] When we look in deep history, it's actually
much easier to track changes in rainfall, But we also see that in the modern period,
temperature plays a really important role. And in particular, as it gets
hotter and hotter, we tend to see it really affect how people make decisions,
their mood, and their propensity for conflict. [Marnie] How much of a temperature rise is needed to
see these effects depends on the situation. But Solomon says an increase in heat and an
increase in conflict go hand in hand – so, as it gets hotter, more people engage in
violent behaviour, and… every degree matters. You can measure this in all sorts of
ways. His approach was to get students to play certain games, and then fiddle with
the thermostat and watch what happened. [Solomon] There's a game called The Joy of
Destruction. Essentially, students can destroy gift cards that they get as winnings.
And they can destroy another person's winnings, for no benefit of their own, they just see that
the gift cards get cut up. And so this is kind of measuring how much satisfaction someone
gets from watching someone else be harmed. We put half the students randomly into an
environment that was pretty cool, like normal room temperature. And half the students went into
a setting in which we really cranked up the heat and made it very, very uncomfortably warm,
and they were in there for many hours. And what we actually saw is that when the students
were randomly put into the hot room, they were destroying over 10% more of the other
students' assets, when it didn't really help them in any other discernible way. What we take
away from that is that the students were somehow enjoying destroying someone else's material goods,
as a response to changes in their environment. We want to be very careful here because there
had been some really contentious political elections happening, just before we were doing
all our experiments, and one of the communities involved really felt like the election was stolen
from them. And it turned out that the students that seemed to be experiencing all that
frustration in the real world, some of it was carrying over into the experiment,
and that was the community of students that seemed to be feeling the most satisfaction
from destroying other people's assets. So people face external frustration. You know, we have to normally try to
contain that, and accept those problems, but in some cases, we burst out,
we do things that hurt other people. And what we see, I think, over and over, is that
higher temperatures give us a shorter fuse. We're less able
to control those frustrations, and they end up coming to the
surface and sometimes hurting other people. [Marnie] Solomon’s research suggests
that hotter temperatures impact how well people can deal with
the stresses and strains of ordinary life – he’s found gang violence and
murders increase as the mercury rises. But is it that we’re all getting hot and
bothered – and reacting more impulsively to stressful situations, or is it just the case that
warmer weather means more people are likely to go outside… and more people on the streets
means more opportunities to commit crimes? Solomon says it might be both. Certainly, car
theft rates go down when it’s too cold to stand outside and break into cars, but there is
a growing school of thought that heat might actually be doing something to our
brains to make us behave differently. Solomon stressed that he’s an economist,
so this really isn’t his field, but he did give me a rough summary: [Solomon] You know, like, a third of the calories
you eat get burned by your brain. So your brain gets really, really warm. It's like
a computer just running all the time. And all of that heat has to go somewhere. And so it actually
comes out in your jugular vein in your throat, down your neck, and then spreads out to your skin
where your skin then releases that heat to your external environment. And so, as
the temperature around you gets hotter and hotter, your skin doesn't work as well, to cool you down.
And so that goes back upstream. And what you see is that your brain temperature actually goes
up. And so it's possible that that is affecting people's judgement, their decision
making, how their brain works. It's also possible that some of the effect of temperature is discomfort or a distraction. And it just makes it
harder to you know, keep it together. And so trying to figure out, you know, which
one of those things it is, is quite a challenge. [Marnie] I know that our body works really hard to keep
our temperatures constant, but it could be that a small change in temperature is basically making
us overheat, a bit like computers? [Solomon] I mean, that seems like it could be the case. And
one of my former students, Patrick Bayless, he did this really interesting study where he
basically just looked at a billion different tweets from all across the United States.
And what he saw is that when it gets hotter and hotter, people tweet fewer smiley
faces and more frowny faces, when it gets hotter people swear more in their tweets. And so it
really looks like something about just like how we feel about the world around us changes as
it gets warmer - it could be that our brains are just like overheating a little or
it could just be something else about you know, our mood, like your caller asked.
[Marnie] Did he establish an optimum temperature where people seemed to be tweeting, I don't know,
like more happy emojis and less swearing? [Solomon] Yeah, so in his case, he found that,
you know, people are very comfortable at the temperatures you would expect. So, I mean,
depending where you are in the world around like 25C. People know when they're comfortable, and they're feeling
good. And I think that's what's good for the human body. I think we
all sort of have some intuition about that. And we try to seek it out, but that's
one reason we don't always realise, I think, how much the environment around us
and the temperature affects our mood. It's very hard to be
so self-aware that you realise that every time you get a little bit
warmer, you also get a little bit crankier. [Marnie] So much of the research into our behaviour and
the weather is irritatingly fuzzy. Growing a human in optimum healthy conditions appears to be a lot
more complicated than growing a tomato plant. Some of us claim to love the winter
cold, others flourish in bikini weather. So what can I say with confidence? Serotonin is a key hormone that stabilises
our mood and feelings of happiness. Scientists who’ve looked at how sunshine
affects the level of serotonin we’re able to process in the spring and summer have
concluded it’s not about temperature, but access to daylight, and outside,
direct daylight, that makes a difference. But it does seem our decision-making
abilities can be affected by warm weather… After a cold spring, we’re
more likely to perform well on certain tasks when we’ve been out in the sunshine. But the heat sensitivity works two ways. Once
we start to feel uncomfortable in that sunshine, when it’s too hot, we become less good at problem
solving and more likely to behave irrationally. Listener Michael wondered if it’s
healthier for us to live in a warm and sunny climate – and it’s a question
which will influence billions of lives, whether we like it or not,
thanks to climate change. There are certain species where an extra
degree of warmth is a matter of life or death. For us it’s more subtle, but
still really important. That's why economists like Solomon are getting involved. Global warming will affect
our behaviours and health, and he wants to know how. Although most of
us don’t have the luxury of moving elsewhere, we are uniquely positioned, as the
species that does all this research, to work out how a warmer world will alter us. So
we can at least face the future better prepared. Thank you to Michael in Australia, for asking
this question and over to him for the credits. [Michael] We’ve reached the end of this week's
CrowdScience. Today's question came from me, Michael in gloomy Melbourne. The show was presented by Marnie Chesterton
and produced by Marijke Peters. If you've got something that's been bugging you,
and you want the BBC team to investigate, write to them. The email address is crowdscience@bbc.co.uk
