Hello, and welcome to the Physics World Weekly
podcast.
I'm Hamish Johnston.
In this episode, we're going to be talking
about climate change.
Coming up a bit later, I'm in conversation
with the author of cloudy with a chance
of warming,
how physicists
are studying
the dynamical
impact
of clouds on climate change, and that's a
feature article that has just appeared on Physics
World.
But first, we're going to explore how astronomers
can better understand climate change and share that
knowledge with their students
and the wider public.
The book Climate Change for Astronomers,
Causes,
Consequences,
and Communication
was published earlier this year by IOP Publishing,
which also brings you Physics World.
The book weighs in at 527
pages
and features 19 chapters
that were contributed
by 20 scientists.
The book was edited by Travis Rechter.
He's an astrophysicist
at the University of Alaska
Anchorage
and an advocate for solutions to climate change.
Living in Alaska, he's witnessed dramatic changes in
his home state, and this led him to
cofound
Astronomers
for Planet Earth.
Travis joins me down the line from Anchorage
to talk about what astronomers can do in
response to the climate crisis.
Hello, Travis.
Welcome to the podcast.
Hello, and thank you for, inviting me today.
So, Travis, what motivated you to edit climate
change for astronomers?
Why should astronomers teach climate change and talk
about it with the general public?
That's a good question. People are often surprised
to hear that as an astronomer. I'm
actively involved in advocating for climate change.
And the reason why is because there's a
a big overlap in the science of climate
change and the science of astrophysics.
And so
in our astronomy classes for many years, myself
and other astronomers have been teaching climate change
as part of our curriculum. When you talk
about, like, the atmosphere of Venus and why
it's the hottest planet in the solar system,
that naturally leads to questions from students about
climate change. And so we're talking about climate
change in our classes, and
our goal is is to help people understand
the science of it because often people
don't hear about climate change from scientists. They
hear about it from the news and social
media.
And so often in astronomy classes, the last
opportunity
for people to hear from a scientist about
the actual science of it.
And, Travis, one aim of the book is
to give
astronomers themselves a better understanding of climate change.
How do you do this in the book?
What topics do you focus on?
Yeah. So for many years,
we have been running workshops to help astronomers
be effective teachers of our climate change, and
I'd say the the most common concern
that my fellow astronomers have is they feel
like they don't know the science well enough.
I've had people say to me, oh, I
didn't really
fully understand radiator transfer in grad school. I'm
not sure I can effectively convey the science.
And the key thing that I want all
astronomers to know is is that no matter
what you know, you already know enough to
be an effective advocate
for climate change solutions.
But what many astronomers feel is that they
want to know more, particularly when it comes
to topics like the geologic history of the
earth.
There's a common misconception
that,
that
climate change is a natural consequence of just
natural fluctuations in the earth's climate. And so
one of the chapters on the book is
devoted to the earth's climate system
to help astronomers
be better able to teach the difference between
natural causes of climate change and the human
causes that are creating the crisis we're in
right now.
And the book also gives advice and suggestions
for how astronomers can incorporate
climate change into university astronomy courses.
Can can you talk about some of the
strategies that that can be pursued?
Yeah. So
there's so many ways in which our astronomy
and physics courses
touch on key concepts that are really important
for people
to help understand
the problem. So,
for example,
simply understanding
how long a 1000000000 years is
can give people an understanding
of the difference between
natural climate change and this the long time
scales on which it occurs
and
the and and the short term climate change
that we're causing right now by using fossil
fuels. There's many other examples. So, for example,
talking about different kinds of light, if you're
discussing infrared light versus optical light or if
you're talking about spectroscopy
and absorption features.
These are all topics that naturally lead themselves
to people being in a better position to
understanding
what causes climate change. It can also lead
to a better understanding of solutions. So, for
example, in a physics class,
energy is a essential concept in every physics
class. And so
if people have
a a fundamental understanding of how energy works
and how it can be transitioned from one
source of energy to another,
then they're going to be in a better
position to understand
the many different solutions that are out there,
whether it be wind or solar or nuclear
and how these different energy sources can work
together.
I see. And and climate change for astronomers
also looks at how the community can better
communicate
climate change to the public.
What's the best practice when doing climate change
related outreach? How do you get the message
out to the general public?
I think one of the biggest challenges that
astronomers face when communicating with climate change, whether
it be with students or the public,
is understanding and appreciating
that
there are many different places again where people
are hearing about climate change. It's not just
from scientists. And as astronomers, we're
accustomed to people being interested
in hearing what we have to say. They
love hearing about black holes and exoplanets
and,
life, beyond the earth. But then when you
start talking about climate change, there's an additional
element to it. It's emotionally charged. It's politically
contentious,
and there's a lot of feelings in the
room. And so as scientists,
we're accustomed to just simply telling people what
we know and anticipating that they're going to
accept that.
And so it's very important for us
to be good listeners. It's not something that
we're often accustomed to doing. We're accustomed to
being in front of an audience and and
talking to people rather than listening.
But if you take the time to listen
to the questions people have, it'll give you
a better sense of
how they're feeling, what their concerns are, what
maybe they've heard elsewhere,
and give you a better opportunity
to give them information that can help them.
The most important thing, I think, in any
interaction is for people to feel like that
they were heard and they were listened to
and respected
and that they'll be interested in in learning
more about it in the future either from
you or from others. So
having a positive interaction where people felt feel
good afterwards is very important.
I see. And and the book also looks
at,
the I suppose the vexing question
of how astronomers can advocate for action
on climate change without compromising their roles
as scientists.
And and that must be very difficult in
in what you say has become a very
polarized debate.
How how how can scientists
do that?
Yeah. That's another common concern I hear from
scientists is that
they feel like they shouldn't enter the fray,
that we should essentially be in our ivory
tower from which we give information to people,
but it is for others
to to solve the problem. And I don't
think that's true. I think there's a long
history of scientists being advocates.
And the reason why it's important for us
to do it is because
we need to share what we know
to help people understand not only the problem,
but what solutions are out there.
Examples, obviously,
Einstein was
a major advocate for
solutions about nuclear warfare.
Carl Sagan is actually one of the first
scientists to testify in front of congress about
climate change back in the eighties.
So
what we can do as scientists that is
share what we know and share how we
understand
different solutions
to make
decision makers in a better position to make
good decisions. And so I don't think, as
scientists, we should advocate for specific solutions or
sole solutions. I don't think, as scientists,
we should say that, for example, just wind
power or just nuclear or just this or
that is going to have a solution. But
but by providing
the information we have
about all the different solutions are out there,
then I think we can we can do,
good to help people understand the problem. So
one of the chapters we wrote in the
book
is just the just describes the pathways
towards solutions. That is how can we go
from the energy we use
now to the energy we want,
and what are the different ways that we
can do that?
And, Travis,
Jeffrey Bennett, who's at the University of Colorado,
has written a chapter called
Teaching with Inspiration,
Not Only Fear.
How can astronomers
provide students and the public with a positive
pathway
to addressing climate change
and building
a better future. I think you you hinted
at one way,
just a minute ago. Yeah. So I think
this is incredibly important for us to understand,
especially with our our students who are younger,
and that is there is a lot of
fear.
It's called climate doomism. It's the the sense
that it's too late, that nothing can be
done.
And what's important I mean, I have students
telling me that they aren't going to have
kids because they don't wanna bring children into
a a ruined world.
And there is a recent study that found
that 75%
of people under the age of 25 are
terrified of their futures. They're scared of their
future.
So one of the most important things that
we can do for our students is to
help them see that we can actually create
a world
that is gonna be good to live in.
And one of the things that I really
like about, Jeff Bennett's chapter is he talks
about
helping students understand what our world can look
like after we solve the problem of climate
change. So often, we don't even talk about
what
that could
be. And, yes, climate change is serious. It
is a terrible problem. Every day in the
news, we're seeing stories about firestorms and flooding
and people's lives being affected or destroyed.
And we're not trying to sugarcoat the reality
of the problem,
but we do know that there is a
path forward. We have nearly all the solutions
we need to address climate change,
but the biggest issue here is getting people
motivated
to actually want to work towards a future
that they could be excited to live in.
And you you mentioned that some of your
students are, perhaps rightly so,
have neg sort sort of negative thoughts about
the the implications of climate change. But I
mean, do you also find that that the
people you teach, there's some positiveness
in there that that people think, yes, this
is something that that we can we can
fix, we can address this, and if I
if I study astronomy, if I study science,
I can make a a major contribution to
solving the problem. Well, I'll say every semester
I'm really impressed with the students that I
have. And so many of them are already
motivated and involved in working towards solutions.
And it doesn't have to be big solutions.
It can be community level solutions working,
within your neighborhood, working within your school or
your classes.
So many kids now understand
the problems of the world in ways that
I feel like that
my generation did not. Our our students
have access to social media and provides
information to them in a way that,
I don't think earlier generations had. I'm continually
impressed with my daughter and her awareness of
of the issues in the world. So this
is a generation that unfortunately is inheriting a
problem that was created by prior generations,
but I'm also very impressed with how motivated
many of them are to address it. And
so
one of the things that scientists often focus
on is trying to convince people that climate
change is happening. And I think what's more
important now is convincing people that we can
address the problem and that they can have
a
role in fixing it. And so so many
of my students, the first question really is,
well, what can I do? How can I
be involved? And so
giving students resources and information,
like, for example, project drawdown is a wonderful
resource
that helps people see all the solutions out
there. It gives them an opportunity to find
the place where they are gonna be most
interested in working.
I see. Well, that that sounds very positive.
And, Travis,
if I can, I'd I'd like to ask
you maybe
something on a more personal level. I mentioned
in the introduction that you've noticed
changes in in your native Alaska
that that have concerned you.
Is it possible for you to to give
us a a few examples of things that
are changing,
because of because of global warming climate change?
Yeah. So I've been in Alaska for over
20 years now, and
in that time, we've seen quite a bit
of change. The Arctic
in general is warming at about 3 times
the rate as the rest of the world
due to the ice albedo feedback loop with
the with the Arctic sea.
I've seen glaciers recede to the point now
where
I have pictures of myself when I first
got here that if I was standing in
that same location and took a picture, you
would not be able to see the glacier.
In fact, there's a glacier near Anchorage called
Portage Glacier
that they built a visitor center for you
to look at it, and you can't see
the glacier from there anymore. It's receded so
much.
There's also,
dire effects for, seafood. When off when often
we think about climate change, we think about
global warming. We think about how the earth
is getting warmer.
But another side effect of climate change is
ocean acidification.
The carbon dioxide releasing the atmosphere,
about a quarter of that is being absorbed
by the earth's oceans,
and that is creating carbonic acid and making
the oceans more acidic.
The fishing industry is the largest employer in
the state of Alaska, and, species like salmon
and king crabs and Tanner crabs are not
only a major part of our economy, but
also part of our our culture and our
identity.
And so
in recent years, we've had the collapse of
several fisheries due to warmer waters and ocean
acidification.
And that's the part that's hardest for me
to see, is to see how
our lives and traditions here in Alaska are
being affected by climate change. And it really
is a major driver for the advocacy work
that I do.
Yeah. It is it is interesting. I mean,
you know, from my point of view, I'm
I'm from Canada originally, but I I've lived
in the UK for for many, many years.
And the the thing that,
you know, I've I've I sort of had
this emotional
tie to to the concept of winter.
And and it seems to me that, you
know, if if whenever I get back to
Canada in the winter,
there seems to be less of it.
And,
you know, there there's
culture and tradition,
where I come from, you know, things like
ice fishing or skating on a on a
frozen lake,
things that I really enjoyed doing
when I was a child. And
I realize now that,
well, the last time I was there, you
just couldn't do it. There was no ice
on the lakes, which was a big shock
to me.
And I suppose I struggle to, to to
not be sad about it.
But it's great to, you know, to hear
that astronomers like yourselves are
are clubbing together to to try to make
a difference, and also that that the young
people that you teach are
are positive that they want to do something
about it. That's that's really nice to hear.
Yeah. It's a it's a it's a mix
of of sadness and optimism.
As I've heard said before, hope is a
choice.
And I think it's important for us to
acknowledge
the the sadness that we feel. I I
like you, I love winter. It's my favorite
time of year. I love snow. I love
ice skating.
And it's been hard to watch how Alaska
has changed in that way. Our winters are
shorter.
We're getting
we get good snow, but we also are
getting more rain.
And
I think every community in the world now
is feeling the effects of climate change. Most
everyone I talk with nowadays
can identify
an event
that has happened that was climate change enhanced,
whether, again, be a firestorm
or flooding.
So people understand things are different now, and
there's sadness associated with thinking that our our
lives and our world has changed.
But
the goal here, I think, is to help
people see that we can still avoid
the worst consequences.
And,
I've heard it quite recently
that if you're not optimistic, you're not paying
attention. There's a lot of good news out
there right now about
the solutions that are out there, and and
they're taking effect. I mean, wind and solar
has grown much faster than anyone,
dared anticipate 10 years ago. So there's lots
to be sad about, but there's also a
lot to be
excited about.
Well, that's great, Travis. That's a great place
to, to to leave it. Thanks so much
for speaking to me today. And listeners, you
can find climate change for astronomers
on the IOPscience
website.
The central thesis of climate change is simple.
A relentless
increase in carbon dioxide in the atmosphere
is reducing the amount of heat that earth
radiates into space,
and that's warming the planet.
There are, however, myriad other factors that affect
how the climate is changing,
including the role that clouds play in both
heating
and cooling the planet.
To talk about clouds and climate, I'm joined
down the line by the science writer,
Michael Allen,
who has penned the Physics World article,
cloudy with a chance of warming,
how physicists
are studying
the dynamical
impact of clouds
on climate change.
Hi, Michael.
Welcome to the podcast.
Hi, Hamish. Nice to be here. So, Michael,
can you give us a a a basic
idea
of how clouds affect climate? I mean, we
all know that when we're outside
and,
a cloud comes over, covers the sun, it
cools down.
Many of us are also aware that
at night
cloud cover can can sort of increase the
temperature
that we experience once the sun goes down.
But I'm guessing that there's lots of ways
that, clouds can impact
the climate.
Yes. But the basic issue is quite simple,
really.
Clouds
essentially play a role in the Earth's radiation
budget, so that's the balance between the amount
of energy that comes in from the sun
and the amount of energy that kind of
is reflected out to space as thermal
energy
from the Earth.
And, essentially,
clouds play 2 simple roles in this. 1
is they reflect some clouds are reflective,
so they reflect the sun's energy back into
space,
cooling the earth.
And then then some clouds
act a bit more like a blanket.
They absorb that thermal energy that's radiators from
the earth, and then they radiate it back
towards the earth.
And the balance between this, you know, the
cooling of the clouds and the warming of
the clouds
impacts
how much heat reaches the Earth's surface.
But as you pointed out, we can see
clouds when we look up, and
there are lots of clouds around. And researchers
tell me that the basic problem is that
a small shift
in cloud amounts
between these different clouds that are reflective
or acting like a blanket can have quite
a significant impact
on the Earth's radiation budget.
And, basically, climate change plays into this because
it affects
how clouds kind of form and develop.
I see. And
I suppose that there's lots of different
types of clouds.
I'm going to show my ignorance here by
referring to high level clouds and low clouds.
I'm sure that there's much more technical terms,
available. But those clouds at at different
altitudes
play very different roles, don't they, in in
Earth's temperature?
Yes. I mean, I'm also fairly ignorant
on the different types of clouds too. But
I think, again, as you point out, on
a relatively simple level,
low altitude clouds, so the clouds that sit
in the troposphere,
the kind of lowest
level of the Earth's atmosphere
are generally reflective, so they are reflecting sunlight
back out to space, while
the higher altitude clouds, which again sit in
the same part of the atmosphere, the troposphere,
but right at the top of it tend
to have more of this blanket warming effect.
I see. And and so how are rising
global temperatures
affecting
cloud cover and formation?
Sure. So when it comes to these
higher clouds,
on a simple level, the heat into the
atmosphere is causing the troposphere to expand
and basically to rise higher. So that's this
lower part of the atmosphere
is rising to a higher altitude. So this
means that those higher level clouds themselves can
also
rise higher.
And then
issues
with rising temperatures
and the effect of them on, like, the
stability of the atmosphere
is affected the kind of formation of clouds
and how
clouds in the lower atmosphere, particularly these lower
level clouds that reflect sunlight back. Basically, kind
of how they form
and the kind of cloud fraction. That is
the amount of kind of cloud in space.
I see. And so so does that mean
that in general,
we're
we're experiencing,
less lower cloud cover
and more higher cloud cover,
which in itself
is
increasing
the temperature
of the planet? Or, I'm I'm I'm guessing
it's not quite that simple. But is that
sort of a a general trend
that,
climate scientists are seeing?
So I think the evidence on low clouds
is reasonably
clear
that
rising temperatures are reducing
the amount of low cloud cover, particularly over
kind of tropic and subtropical
regions. When it becomes to the higher level
clouds,
I think that the science is a little
less clear at the moment. So these clouds
are rising,
and the assumption is that that also
increases
this kind of blanket
blanketing effect,
but
it's not really clear, I don't think yet,
exactly what else is happening to these clouds
as they rise.
So there could be other changes in them
that also
impact
their impact on the Earth's radiation budget.
Right. And I I think in your article,
you do mention
things like, you know, what percentage of a
cloud,
is made up of liquid droplets,
and how much is ice, and how that
is changing, and how that affects,
climate. So it is it is a very
complicated system, isn't it?
So, yeah, now we are getting into what
are known as mixed flay phase clouds, which
exist in the northern and southern hemisphere, kind
of outside of the tropical regions. And these
are clouds that are a mixture
of liquids,
water,
and ice.
And the basic
problem here is that as these clouds warm,
they shift from being
more ice to being more liquid, and thus
they become more reflective.
So they are bouncing more of the sun's
energy back into space,
and this has a dampening effect on climate
change.
But problems have arisen around how these clouds
are modeled,
so it appears
well, research has shown that
simulations
have been modeling these clouds to to start
off being
having higher proportions of ice than they actually
do.
So
that means that they can become
there's a kind of bigger shift in their
reflectiveness, and it's happening in reality. So that
kind of affects
how these climate models
simulate
the change in the radiation budget
as these clouds move from ice to liquid.
And one important part of this is that
at some point, these clouds become kind of
predominantly
or entirely
liquid.
So that means
they their their increasing reflectiveness
stops.
So whilst the earth is warming with climate
change,
to start with, the reflection this is this
of these clouds is increasing, having a dampening
effect, but then it slows,
and then it stops increasing. So the reflectiveness
is still there,
but it remains at that level whilst the
heat of the earth continues to
increase. So you get a slowdown
in this dampening effect that the clouds have.
So, yeah, Michael. I mean, it sounds like
it is a very complicated,
relationship between clouds
and climate.
In your article, you also mention other sort
of effects that humans
are having on clouds, and and in particular,
aerosols.
It you you point out that,
if we reduce,
aerosol
emissions, which is very important because aerosols can
be lethal,
in terms of,
causing things like lung disease.
That could actually lead to more
warming.
So why,
our efforts to cut
aerosol
emissions,
Why are they counterproductive
when it comes to battling
climate change?
Yeah. Sure. I mean, you point to quite
a dilemma here for kind of climate scientists.
You know, we need to reduce aerosol pollutions
because like you said, they have a huge
health health impact.
They're globally, something like 8,000,000 people die every
year from air pollution.
But,
basically,
when it comes to clouds,
aerosols
in the air pollution
reduce the size of the cloud droplets,
and this makes them more reflective.
So they bounce again more of the sun's
energy back out into space. So when we
cut the amount of aerosols we're producing to
tackle this dangerous air pollution,
we make the clouds less reflective.
So more of the sun's energy gets through
and heats the earth.
And so there you know, there's a bit
of debate around this,
but, you know, some people started to argue
that actually if we were to cut all
the aerosols
and slash pollution,
you know, in the way that some countries
are trying to do, it could have a
pretty significant
impact on our chance of keeping global warming
below 2 degrees.
And other people I've spoken to suggested that,
essentially, if we removed all aerosol pollution, we
could create anywhere between an extra point 2
to 0.6 degrees of additional warming.
But, of course, we have to do it
because we can't allow people just to be
kind of dying from
heart and lung disease because of pollution.
Right. And I suppose the other thing is
that some of that aerosol
emission will will be related to
carbon dioxide
emission as well, won't it? So, you know,
burning dirty fossil fuels, etcetera.
So, I suppose in in some cases, you
could you could reduce both aerosol emission
and carbon dioxide emission at the same time.
But I suppose that's you you have to
be worried about the effect of reducing the
aerosols.
Yeah. Of course, these things are linked. They're
they're not necessarily
always the same sources, but they come but
they do come from very similar
industrial processes, fossil fuel
burning processes.
And I don't cover this in the article,
but I think research has suggested that one
of the best ways to deal with this
really is just
to slash both. So you are cutting the
global warming element of the carbon dioxide emissions,
and
this kind of
feedback
from the aerosols.
I see. And and I I suppose something
that's related to aerosols
is,
the idea of cloud
seeding.
I suppose this is a
is this called a a geoengineering
technique where we we try to increase,
the right kind of cloud cover in order
to
counteract
climate
change. Yes. So
I guess
the issue with the aerosols
kind of opens up a question, which is
basically,
well, can we use
aerosols that are perhaps nonpolluting
to mitigate climate change? Can we make the
clouds more reflective
ourselves?
And the idea behind this or the sort
of idea that people proposed this is basically
to use
salt water
spray
as an aerosol. So I guess you would
take a ship or something like that. You'd
suck up
seawater.
You spray it out, and the idea
is that this that this that the that
it kind of evaporates
and the fine haze of particles,
the salt, and the other things in the
seawater
are transported into the clouds by air currents,
and that reduces
the droplet size in clouds
and increases
their brightness.
I see. But I suppose the problem there
is that if if country a is really
suffering
from climate change and decides to do this,
aren't some of those clouds going to drift
over, let's say, country b?
And,
you know, I suppose block out the sun
and maybe affect
its agriculture,
or maybe country b is not suffering as
much from from climate change. Maybe it's a
bit further north or or something. There's aren't
there huge geopolitical
issues here
when, when these sort of schemes are rolled
out? Yes. I mean, obviously, we're moving beyond
physics here and,
there is something for
politicians
and society to discuss about how these
technologies would be deployed. But exactly,
you can't
really
just do this
in one place.
No. If you start if you just chose
chose one location in the world to do
this because you want to increase the reflection
of the clouds there, that's gonna going to
start to have kind of few, you know,
it has the potential to have knock on
effects to local
circulation patterns and things if you're kind of
cool in the air in that area. You
know, it yeah. It it becomes really
complicated.
So a lot of research really is needed
to model
exactly how this
such a technique
would alter the clouds, but then
going up to a much larger scale,
how does that alter the clouds then affect
the local climate
and then a kind of larger, I guess,
local climate and then the
Earth's global climate.
And then really, yes, I guess, as a
society or societies,
we need to decide
whether or not we want to allow this
technology to go ahead and how we manage
it to ensure that
everyone is getting the benefits from it rather
than the situation like you suggest
where some countries are doing this and benefiting
themselves
whilst having negative knock on effects for people
elsewhere.
Well, thanks for talking about clouds and climate
change, Michael. It's, I mean, it's an it's
an incredibly
complicated,
field of endeavor, and I'm sure there's lots
of physicists and other researchers out there working
very hard on improving
our understanding of it. And if you'd like
to, to read Michael's article, you can find
it on the Physics World website.
It's under the headline,
cloudy with a chance of warming, how physicists
are studying
the dynamical
impact of clouds
on climate change. Thanks for coming on the
podcast, Michael, and thanks for writing that article
as well.
No problem, Hamish. Thank you for talking to
me.
I'm afraid that's all the time we have
for this week's podcast.
Thanks to Travis Rechter and Michael Allen for
joining me today.
And a special thanks to our producer, Fred
Ailes.
We'll be back again next week when we'll
be exploring the amazing properties
of metamaterials.