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Welcome, Kate.
Or shall I say say
who say, all right,
I'm having the honor and the pleasure
to introduce to you three people
here for the first lecture and say
who will start PGD
doing a Ph.D.
concerning environmental upset
in which university?
Hidell back.
All right.
I noticed here that for some people,
climate change seems to be just
news that's passing by.
For some of us, it's a little bit
more fake news.
Someone this morning called it even,
uh, he called for some
good old global warming.
I noticed.
And I think we all need to reconsider
solutions.
Otherwise we could end up in
a kind of a la a couple of
the is to you.
Please give her a welcome applause.
Hello, everyone, is this working?
Hello?
Hello, can you hear me?
Oh, fantastic, I was just not used to
that. OK, fantastic.
Welcome to the talk about climate change.
Why am I here?
Last year I was at Congress and I talked
to some friends about
climate change and they had a lot of
questions, really basic questions and a
lot of open issues.
And I'm not used to that.
Like in my surroundings,
everyone is working with us.
We know a lot of us.
And it was not clear to me that there's
a lot of need for information
out there. So I prepared to talk
and apparently it was really, really
popular. So now I'm here
and I will show you about the basics of
climate change and
I will invite you to become part of the
climate conspiracy with us.
So, um,
what are the basics?
We have to use
two bodies in space.
There's the sun and there's a planet
or a rock.
And they don't have any way of
interacting with each other, with
each other, apart from electromagnetic
radiation.
You can see here, there is
a lot of distance between the two and the
only interaction possible is light.
What is light about?
As you know, you can deconstruct light
into its components.
You can see a rainbow if you use visible
light for that, as you can see here with
a prisma.
And if we do that for sunlight,
we see that
there's a large mÃ¡xima in the visible,
visible part and the green to be exact,
and of course, that's not a coincidence.
And there's also a large part that we
cannot see that's on the right,
the long
tail, that's infrared light.
You can feel as warmth and on the short
list is short sighted.
There is a bit of infrared
ultraviolet radiation that is harmful
to the skin. So this is what arrives at
the top of the atmosphere.
This kind of spectra you can see at the
bottom, it's the wavelength, which is a
parameter that gives the energy of the
light. And you're going to see that a lot
during this talk on the other axis, you
have the intensity of the light.
So a lot well, high
values mean a lot.
Low values mean only a little.
And this is a new spectrum that's been
taken on the ISIS, where they have
monitored this spectra for over
nine years all the time to
see the changes within one solar cycle.
So this is a very
important area of research to see how
this changes.
So, um, if you've
done physics before, you
have probably seen this kind of forum
before.
It's this form, it's.
Given by Plank's law planks,
a plank found this law in about
nineteen hundred, and it gives the
relationship between the temperature of
the body and the radiation that comes out
of it.
We see that everybody that has
a temperature higher than zero Kelvin, so
nothing emits energy.
You can feel it when you touch warm,
when you touch anything, you can feel
some radiation coming off.
And if it becomes warmer, you put
something in the fridge, it
radiates off more energy.
So this is the relationship.
I put the formula at the bottom.
Don't be surprised.
At the same time, if you do
the derivation.
To see where the maximum is, you can see
that it's simply it's simply inverse to
temperature.
And as you can see here, there's a buddy
that's very hot, it's a 2000
Kelvin, there's a body that's only 1500
Kelvin and a body that is
only a thousand Kelvin.
And you see that it gets less,
but the maximum also shifts.
So why is this interesting?
Let's look at the temperatures of the sun
and the temperature we have at Earth, Ms.
I did this in Python and
I typed a little, so it's close
enough, it's fine.
And you can see here that you can
see nothing.
Let me set that up,
you can see there's a to the power
of the minus seven on the
on the right side,
and that means that
there's a large difference in
intensity between those two bodies.
But what is really interesting is
this part.
There is almost
no overlap between these two spectra.
So the radiation coming off the
sun and the radiation coming off
the earth, they
are very, very different in energy.
Why is this interesting?
And we can now calculate
the temperature of the Earth would have
it if it was just like this simple
energy equilibrium,
there's another parameter we need because
the spectrum, the thermal
radiation spectrum describes
the sun fairly well, the earth
not so well.
And the reason is that the earth also
reflects light and
the ratio between the incoming light and
the reflected light is called albedo.
And just to demonstrate this, I
put an object with high albedo and an
object with low albedo here.
And you can see that one of them absorbs
all incoming light and the other one
reflects all incoming light.
And so you can imagine that
the person who is
here with a low albedo will become very
warm after some time and also start to
radio off the radio out of heat.
And you can imagine that the
wavelength, they will radiate off
if they didn't have internal energy,
whatever will be different.
So Earth has an average of about,
oh point three, 30 percent of the
radiation coming in from sun, from the
sun is directly reflected
off.
And you can see here I put a green dot
there and I put these green dots
are places where we have a chance
to change parameters concerning
the system.
So if you see this green dot and if
you don't see you just think about what
should we do to change parameters
of the system to to change what's
going on. So he has one one chance.
We have something
that has high albedo on earth is
snow. Fresh snow reflects about 90
percent of incoming light.
Something that is dark is
the ocean, the ocean reflects
only about 10 percent of incoming light.
So you can imagine that if
ice on the ocean goes away
and open seas there,
you get a change in this reflected value.
At the same time, you can just paint
stuff white and you will also get a
change. So.
If we add this together,
we get a temperature of minus 15
degrees on the planet.
This is not true, you know this
I'm happy it's not true.
And the reason is that we have an
atmosphere.
What does an atmosphere do?
It can interact with light.
There's a lawyer that's been found by
elaborate and fair to different people
who found parts of it at different
times, 1729,
1852, as you can see.
And it describes how light is absorbed
in the gas or in a body.
I put the formula here because it's very
easy and telling that there
is an exponential decrease in the light.
And it depends on three parameters.
It depends on the distance.
The light travels in the gas
well, it depends on the
density of the gas or how much how many
molecules of the gas, whether it's ROE
and there's a parameter called Sigma,
it's the absorption coefficient.
And this is gas dependent.
It's also constant, so it doesn't change
over time, it doesn't change change a
little with pressure, with pressure and a
little with temperature, but not really.
And we measure this in lab.
So this is a very well researched law.
And you can also research your
if you want or in the hackerspace or
whatever. It's really easy.
So what
are the consequences of this?
I brought you a picture
of Natu, you know, the
diesel scandal, gas
not very healthy, so don't breathe it in
and you can see different concentrations
here. We have almost nothing
up to a very high concentration and you
can see that it gets darker and darker.
I also put the absorption
coefficient down there and I also
painted with colors, the
wavelengths you can see.
As you can see, there's a lot of
absorbtion going on in the blue wavefront
way, fringe wavelength range
and not a lot in the red wavelength
range, and these two images are linked.
If you.
Had to guess from the plot which
color the gases.
Or you should be able to do that now you
can say it's Redish because the red can
pass through.
So we
have this effect in the atmosphere.
We have gas that absorbs
in the infrared, but not in
the visible.
Let's run our calculation again now we
have an atmosphere here, there's 100
percent of light coming in from the top.
It goes down to the atmosphere, 30
percent, as I said before, is already
reflected back.
So this does not concern us all unless
we want to change it. But yeah,
and 47 percent are
absorbed by the ground.
The ground heats up. You can feel those
if you put your hand on the stone when
it's sunny.
And the rest is already going into the
atmosphere.
Now, what does the gas
actually do, as you can see,
about 12 percent can make it through
of the of infrared light,
the light with a lower wavelength with
a with a very long way French wavelength
and.
It can go through, but
a lot of it cannot go through, it
will be absorbed by the atmosphere
immediately, so the lowest layer
of the earth heats up.
It becomes warm as well,
so it starts to radiate as well,
depending on the temperature.
It will radiate at different wavelength
ranges and at different
intensities, but it's still going to be
in the absorption area.
So at the wavelengths, the gas
absorbs, it's also going to emit.
I'm going to show you later.
And this effect also starts
to further layers.
So the next layer of the atmosphere will
also absorb
some of the light coming from the
downwards direction.
It will heat up.
It will start to radiate.
This radiation is going.
All directions so apart will
go back down and in the end, you get
a radiation level
of about 97 percent of the
incoming sunlight going back down.
So about twice the level of the
sunlight that reaches the ground
is coming back down from the atmosphere
again.
And if you run the calculation on that,
you can just run the sums here.
You can see that one hundred forty four
percent of the lights are
actually radiated out.
So the.
Black body temperature that you get at
the earth is higher
than it would be without atmosphere.
We got about 15 degrees Celsius.
This is the real temperature we have,
so this is actually a very nice effect.
We call this the greenhouse effect, the
natural greenhouse effect, and
it's useful for life on Earth because it
protects us.
I can show you the same
thing in Spectra.
The top spectra shows
the BlackBerry radiation of the ground.
So you can see it's very smooth.
You can also run the calculation on that.
You get the same plot in the next
part, you get the downwards
radiation.
So the gas absorbs
in the parts that are
elevated here and,
uh, absorbs
and heats up
and emits again.
So this coming down, this is what you can
see if you if you measure the light
coming down.
And at the same time, there's
a natural a sort of the difference
between the plots is
the bottom part.
And you can see that there's a window
where the light can go out and
parts where nothing,
almost nothing of the light makes it out.
I also know well, the plot has
marked the greenhouse gases that
act here, you can see that a large one is
water, H2O.
Ozone also plays a significant role here
and CO2 is a
large part.
So the question is, what happens if we
change the concentrations of these gases?
What happens, in fact, is that,
oh, let me see.
But this part here gets
broader.
And this part here gets smaller.
So the outgoing radiation is
less.
So the ground heats up, it's a bit
more complicated than that, of course, if
you run the calculations, you get a lot
of changes in the vertical profile,
but that's the basics.
At the current level, we have about all
point eight watt per square meter
of energy coming in, that's not going
out.
He is an advanced concept.
I just wanted to show you briefly,
it's also connected to the black body
temperature.
At the same time, it tells you
about the black body temperature of
different layers of the atmosphere.
You can see that in the window.
You can actually see the ground.
The ground has a temperature of 15
degrees.
And you can see in the
and the outgoing radiation here,
the radiation you measure from space.
You can see that you can see the
the photons from the ground at
the same time in the water
absorption areas, which
are two here, you can see that it's
about minus 30 degrees.
This light comes from
an area where the light the air is minus
30 degrees. So in
the stratosphere already.
Maybe top of.
Whatever, um, at the same time,
you can see that ozone comes at minus 10
degrees, that's the top
of the stratosphere.
So the top of the ozone layer
and we have CO2,
which comes from from a level of minus 55
degrees. So you can see here which
height.
The light comes from and at
which layer the air
is transparent for this
wavelength ranges.
I'm sorry if this is a bit complicated,
you can ask me later about details.
Let's keep going with
increase of gas in the atmosphere.
This is the current plot.
I just pulled this from the Mauna Loa
Observatory page of Noires yesterday.
Um, you can see that they
have a continuous record since is 1960s
to today and their
current level in September was
four and two p.m.
parts per million.
And you can see that is oscillating,
this is due to the fact that
the hemispheres have summers and winters
and the North has a lot of plants,
the south doesn't have a lot of
ground, so it doesn't have so many
plants. And the plants operate
more in summer and winter.
So you can actually see the plant level,
the plant life here.
OK, so, um,
what do we do with this?
We can run a very simple calculation
from what I showed you before, you know,
not everyone, everything you need to run
a very simple climate model.
If we increase the CO2 level twice,
you can get a temperature increase of
one point two degrees Celsius.
Now, if you compare that
to the increase we had already back from
the past, you can
see that there's a mismatch there.
So what is happening is that there's a
lot of feedback mechanisms.
We have energy coming in, the energy
can melt, water can
melt, ice, changed the ability of the
earth, it can generate
more clouds. There's more energy, more
water can be
evaporated.
More clout can be generated, it changes
the albedo or changes the outgoing
energy.
Um, level and
the temperature gradient change, there's
a lot of feedback mechanisms and
we come to a result
of about, oh, one point five to
four point five degrees Celsius
from this.
But you see there's an error range there.
We'll talk about that later.
We call this concept climate sensitivity,
it just says how the climate system
reacts to a doubling of the CO2 content.
So the question is, we have too much
energy going in now because
the sun.
Gave us energy and it's not going out
anymore because there's a barrier there
now. So where did it go so far?
I already told you that there is a plus
of O point eight
watt per square meter coming
in, but we don't have a heating
that corresponds to this value.
So where did the energy go?
So far, I talked about
basic laws, basic physics
laws you can easily measure in your own
lab that physics students all over the
world measure every year.
And so far I didn't find a mistake.
Now I'm going to talk about
measurements that.
Fit together with a result that we
have an energy overlap
energy over too much energy.
So where does the energy go?
So far it seems to go into the ocean.
About 93 percent
of the energy go so far went into
the ocean.
This plot shows you a few data sets
that all have the same.
A conclusion, the
upper layer of the ocean that's
top part warms up.
The lower layer, the deep ocean
also warms up, that's the lower part,
so this is where the energy goes so far.
He is another place where the energy
goes, it's
a plot that shows the ice extent
on the Arctic on the top.
In an annual way, and the
lower part shows it
is all for different months
and it's different data sets, different
colors, different data sets, and you can
see they all agree it's going down.
So here's another sink of energy for us.
And if we add these together,
there's the
expansion of water due to heat,
you know, things that warm up expand
and there's the expansion
of water content due
to ice melting.
That's the lower two curves.
And if you add them together, they feel
fit very nicely
to the curve that shows
the measured increase in sea level.
So this follows from very basic physics,
this is where the energy is going.
If you don't if you're not convinced
by this yet, I have more plots,
I'm not going to discuss these details.
There's a few plots here that correspond
to air temperatures.
I marked them with air and there's
a few plots that are
corresponding to see temperatures and sea
ice.
Sea temperatures, sea content
and snow and ice are also there.
And you can see they all agree we have
two data sets
in minimum and up to seven data sets
here. They all agree.
So the data
is also there.
So what we know so far, the basic
physics tells us that
an increase in any of the greenhouse
gases will lead to an increase in
temperature.
There's feedback mechanisms and we don't
know exactly
beriberi exactly what that lead
to, because there's an error range on the
climate sensitivity.
And we see that the data shows an
increase in energy uptake
in the system.
Where do we go from here?
We have to run models,
so what we do is we know we
use these basic physics laws.
We parameterize
the earth and we try to calculate
the response of the system.
Now, I only discussed very, very basic
things here and there's a lot more
impact factors on the climate.
You can talk to me later if you want to
discuss this.
No problem.
The main ones here are aerosols.
So particles in the air that shield the
heat while the incoming light a
little. There's clouds that can change
this ozone and the chemistry that
also is a climate gas and
can also shield
light and of course, the emissions
of greenhouse gases and aerosols,
which are also not known for the future.
A few more are there.
So it's a complex system.
We're trying to model this,
but some
things are still unknown.
Some things might be unknowable because
we're talking about a chaotic system
here.
It's clear, however, that we have
this energy energy surplus
and that it's going somewhere,
so there will be
consequences of this physical
consequences and physical consequences
also mean that there will be consequences
for people on Earth.
And my colleague will now
my colleague will now
tell you more about that.
So if you have any questions about the
climate system and the basic physics
or the data, just come talk to me.
You can also read the IPCC report.
It has a lot of plots, a lot
of plots. And you can
learn anything you want to know about the
data from there also.
So just check it out.
Thank you.
OK,
since we know fairly well about
the greenhouse effect
and well, with some confidence,
we can also project the temperature
on average
for the next coming decades.
Of course, that depends on how we
emit further greenhouse
gases. So if we continue emitting,
we'll probably end up by
at about four additional
degrees Celsius.
If we really manage to
to mitigate a lot of our emissions,
we might even manage to get
below two degrees.
Well, but what does that mean?
Well, one of the most
well known impacts of climate change is
sea level rise.
Like I just said, the mechanism there is.
Not very simple, but at least
easy to understand, because when
oceans heat up, they expand, that
gives a big contribution to sea level
rise.
And of course, as the temperature
increases, we'll melt snow
and ice, especially in the
glaciers on Greenland and
Antarctica.
So knowing the temperature,
we can also project
quite well the
sea level rise that we have
to expect in the coming decades until the
end of the century.
And we might end up at one
meter sea level rise on average
or maybe managed below that.
But all these things that we set in
motion, they're the melting of the ISIS
is actually quite a slow
process.
So even after 2100, even after
we have emitted even maybe after
humanity has ceased to exist,
the ice is still melting and several
additional meters of sea level rise are
expected to to um.
Yeah. To be there.
Well, OK.
Sea level rise
probably affects coasts and
islands, but what does
the warming itself do with the economy?
How does the economy react on
climate change?
Of course, that's a very difficult
question to answer.
But we can start with
kind of simple observations.
So this is from a fairly
recent study by scientists
in California who
looked up, who looked at the.
Well, we looked at the
change in GDP
per capita, that is kind of like the
average income a person has in the
country, um,
in the last 50 decades and tried
to find a relation to the
annual average temperature there.
So in there, they account, of course, for
specific variables that the countries
have, if they're poor, if they're rich
to begin with.
And, well, they find this kind of
you shaped relationship
between those two.
So what OK, if we know the
annual average temperature, how does
that affects the the the the
the GDP per capita?
OK, let's try to extrapolate that.
And if we extrapolate that, they find
that, well, regions that are
already warm, kind of like
beyond the curve,
even go down the slope when
additional warming occurs and colder
countries might actually benefit because
they get up the curve.
But this is a fairly simple
econometric model.
So it just accounts for the direct
impact of the temperature on economic
activity.
And if you can really extrapolate that on
the climate change, we don't know yet.
Another very important number
that is discussed in
climate economics is the
so-called so-called social cost of
carbon, because we might ask,
well, if you emit an
additional ton of CO2 or
another greenhouse gas,
what damage does that
does that mean along the roads?
So if you think of
a simple coupling of economic
and the climate model, um,
you can say that, OK, the economy
produces that leads to emissions.
The emissions in the climate system lead
to to to
temperature change.
And similar to the
to the relationship I just showed you,
the
average temperature change might
come with a damage.
So we put in there a simple damage
function that gives us,
depending on the additional temperature,
additional damages on the economy.
We can run that in the model.
And then we ask, well,
let's put one additional tonne
of CO2 in there.
How many damages do we get additionally
along the road
in a formal way that looks like that.
So if emit
an amount of carbon
at the at you know,
the temperature reacts.
So this relationship is given by the
climate model in the model.
This temperature change then leads to
a change in climate damages.
This is given by the damage function.
And then we just sum up all these damages
that occur along the road
due to this carbon emission and
summed it up, but.
What is done in economics
on very common in there is
discounting that it's just basically
because of the fact if I offer you
10 euros in a year,
you'll probably prefer me to
offer you 10 years for tomorrow.
So you value these 10 euros
tomorrow, more than those in a year.
This is so this devaluation
of the future in comparison
to the present is given by the social
discount rate.
How does it look like if you run this
kind of model?
Well.
Depending on the
on the year and the emissions so far in
the model, we'll get some damage.
This is the famous
model. It's actually quite simple
and we are currently
trying to make that more accessible for
people who know Python to
play around with that.
Um.
We can start with a social discussion in
here, which is normally used with one
point five percent in that model,
so that means you kind of gray
out the future in a way from the symbolic
point of view.
So we could care more about the damages
here than here.
But if you increase the social discount
rate these
going out because more and
more into the present.
So we don't really actually with seven
percent social discount rate, we don't
really very much care about the
end of the century, but more about the
few, one or two decades to come.
And why is that important?
It is very important because
these these kinds of models
are very, very sensitive
to the social discount rate because,
well, if you don't value the
damages along the road
as much as the damages tomorrow,
of course, we'll have less damages
overall and we probably don't care
so much.
About the overall social cost of carbon.
So if you stick with one point
five percent, this country to start with
20 dollars per tonne and
up to over 100 in two thousand and one
hundred.
The peculiar thing about that is that
the US government actually
uses these kinds of numbers
because in the 1980s they established
a law demanding all
federal agencies to make a cost
benefit analysis of their actions.
And if those involve carbon
emissions in a way, they have to take
into account the social cost of carbon.
So it's a very political no in that way.
And the
Obama administration.
Used a social discount rate, which is
more like three percent, and
came up with lots of
models, an average around
45 dollars per ton.
Now, what the Trump administration,
which has kind of a different
goal there, decided
to have a socialist goal of seven percent
and only look at damages
in the US and not on the whole globe.
So they come up with only a couple
of dollars per ton.
So in the end, this kind of discussion is
still ongoing and very much comes
down to an ethical question, the ethical,
ethical question of how
much do we evaluate the
damages that future generations
will have to cope with in comparison
to the damages that we have to cope with?
OK, still, this is
very simple economic model and with
very simple climate model in there,
so totally neglects another very
important kinds of impacts and those are
extreme weather events.
Extreme weather events are much more
difficult, of course, to model in
comparison to looking at these
temperature increases on average,
but.
So the discussion, for example, for
Harrigan's is still going on if they get
more frequent or more intense, but
as Katya explained to you,
due to climate change, we will have more
energy and the whole earth system.
And so we will probably get also more
energy in the hurricanes, especially
since they feed from the from the
what? The heat of the water under
there.
And as well, they need
a certain temperature to exist on the
ocean surface.
So if the if
the oceans warm, they might even cover
a larger area.
So just as an anecdote, in the
last hurricane season, the Hurricane
Ophelia
reached Europe and thus really got
off the charts of the
grids that the US Hurricane
Center uses.
Well, you probably also heard about other
kinds of impacts, which are floods and
droughts and also here.
Um, the.
Basic physics at least tells us
that if
air warms, it can hold more moisture
and so wet regions
probably also get even wetter.
On the other hand, hot and dry
regions warming
probably also get drier.
What does that mean for society?
Well, indirect effects on society
are displacement and migration.
So just as an example, in 2015.
Weather related events alone
displaced 15 million people across
the globe, displacing means,
well, they might have to move.
Well, to their neighbors,
or they might have to move to the next
village or they might even have to move
across borders.
All in all, we know that these
kinds of impacts and these changes in the
climate system will put.
The societies on Earth on the additional
pressure, so.
Societies that are already
prone to ethnic
riots, for example, or or or
are not very stable in their political
system, probably
are also.
Going to experience more conflict,
but this discussion of the relationship
to climate change is still ongoing, but
at least we know the pressure on these
societies is going to increase.
Well, and we might say, OK, why
do we care? Why do we care in Europe?
You might be able to cope with
with floods because we are rich
in comparison to the rest of the world.
Um, well,
the world is increasingly interconnected
economically.
So supply chains of corporations
nowadays, nowadays across
several countries and our trade
relations get stronger and stronger.
So even if there isn't
an event in
Bangladesh happening, for example, we
probably experience some
effects of that down the road that might
go from price changes, but also to
supply failures.
So we will also suffer from damages.
Just.
Not
right now.
OK, you can hear me great.
Um, OK, so
next, um, let's have a look
at, um,
global emissions.
So this is, um, global
greenhouse gases. Over time,
the red line.
And yeah, we can see that
clearly. They have been more or less
steadily rising over the past decades.
And Gray, we can
see the range of projected emissions
from the climate action plans of
countries.
So this climate action plans
are nationally determined, contributions,
uh, short.
And he sees a part of the Paris Agreement
process.
And each country individually determines
what they want to do, um, to reduce their
emissions.
And the range is so wide because each
country, um,
makes their own plans and are difficult
to assess. Some countries might,
um,
or might rely on
economic growth. For example, one country
might only give out, um,
a target that they are very sure to reach
and other countries might have
difficulties reaching.
For example, Germany is not even on track
to reach the 2020 goal.
And if you compare that to this
range with, um,
the range that would be required to stay
below two or even one point five degrees,
we can clearly see that we are not
even close to that.
So in green and biology, you can see
these ranges.
Um.
So what should we do?
Maybe should we start hacking the climate
if you're not reducing emissions fast
enough?
Geoengineering as a topic that has been
widely discussed in the past
years and especially last months and
weeks, there have been lots of articles
in The New Yorker, The Economist
wired all the Spiegel
and also the NGOs published warning
reports.
And, um,
of course, the scientists also, um,
published many studies and.
Yeah.
So why is it important to
talk about, um, geoengineering and
removing emissions from
removing carbon dioxide from the
atmosphere, the particularly
part of all scenarios that are used
to assess, um, our chances
to stay below two degrees.
So years one stylized,
um, scenario, the red line is,
um, emissions pathway and the
Bronner's um,
um, yeah.
Area shows the CO2 emissions and
emissions from other greenhouse gases.
And below the zero line and blue, we
see emissions that are being removed.
So negative emissions.
And if these negative emissions get even,
um, larger than what we emit,
as you can see at the end of the century,
then we might even be reducing
CO2 concentrations in the atmosphere
again.
So can we do that?
One easy way is to simply plant lots of
trees, afforestation,
and make sure that these trees never get
cut off or burn.
Um, another more technical approach that
is part of all these scenarios of
most of the scenarios is a technology
called PAX and
extends for bioenergy with carbon capture
and storage. And it basically means,
um, producing bioenergy, as we all
are already doing.
So, um, planting crops
or fast growing birds and then
transporting these biomass to a power
station, burning the fuel.
And, um, capturing
the carbon that is released again and
the, um, the burning process
and then storing this carbon in
geological storage sites deep
underground.
So this sounds like a great idea.
And if you think it through, it means the
more electricity you produce with,
um, respect,
the more CO2 you move from the
atmosphere. So if you were driving a car,
um, that would be powered by electricity
from Becs, the more you drove your car,
the more you moved.
But of course, such a technology doesn't
come without its disadvantages.
So to really make a difference, um,
it would require, um,
huge areas of land.
So in some scenarios that can be
up to the size of one or two times
of India. So India, um,
over Europe.
And it's clear that having
so much, um, additional
land use and farming land required
would not be without problems.
So there would certainly be competition
with, um, food production.
So potentially rising food prices.
And it's not easy to produce,
um, such large amounts of bioenergy
without heavy fertilizer usage and
then potentially losing and biodiversity
loss and all the problems that we already
have with sustainably producing,
uh, things that agriculture.
Another problem is that we need to,
um, move all the biomass that we need
to the power stations, and then we need
to, um, transport the
CO2 that we captured
to the sites what can be stored.
So that would require building a huge
network of pipelines.
And it seems likely that few people
want a CO2 pipeline in their backyard
and also not a CO2
storage site.
And in fact, now already in Germany, they
are, um,
in some federal states, there
are laws, regulations against having such
sites because nobody wants them.
So carbon dioxide removal, like Becs,
is a technology that directly,
um, works
or attacks the main cause
of climate change. So reducing carbon
emissions that exist, other
geoengineering ideas that work
more, um, against the impacts
that we saw.
And one of these is solar
radiation management and more
specifically, um, stratospheric
aerosol injection, as the
idea here is to mimic what happens
to a volcanic eruption
and to, as we saw on the first part, from
couteur to reflect back
incoming sunlight so that it doesn't
reach the earth, of course,
was a volcanic eruption.
Then, um, the
reduced temperature is gone after a
couple of years. So we would have to
artificially using airplanes,
bring small particles to the stratosphere
and do this basically forever.
Um, this also points to one
of the main challenges of this proposal,
if you at some point would have to stop,
um, this for technological
or economic or maybe a war reason,
then all the global warming that would
mask and prevented by this technology
would then quickly be added to the
warming we got anyway.
And it seems certainly bad to have a,
uh, fast termination shock like this
and a slow, gradual temperature rise.
Another problem is that,
um, who gets to decide
about the optimal global temperature?
It could be that in some northern
countries. Um.
So people would accept higher temperature
and some people in, uh.
A low-Lying island
threatened by sea level rise that would
rather one temperature rise to stop
immediately.
And looking at the current climate
negotiations process.
It seems unlikely there would be
an agreement found in a short
time.
Another idea that
was discussed in the comic book story
from 1988, where I took most of these
pictures from, was to simply
freeze water, to reduce
the sea level.
So he asked Scrooge, um,
what to profit from a volcanic eruption
and install large, um,
cooling stations at the North and South
Pole and then have lower temperature
and freeze the water again
to have wide stretches of land across the
coast to build hotels there or
do farming and make a profit.
And the story didn't turn out so well.
But in fact, real scientists and
the last years
have looked what it would take to pump
water back onto Antarctica and let
it freeze there again to, um,
prevent sea level rise.
And that study looked what it would take
to rebuild the Arctic ice.
And both studies use wind power
to to do this.
It turned out that is quite difficult
and also, um, quite
energy intensive. So for Antarctica,
it would require about seven to 14
percent of global primary energy
production to pump all this water back.
So it seems all these approaches are
either very expensive or
potentially dangerous or both.
So what should we do with these
geoengineering ideas?
Certainly we should continue researching
them, but we should also be very
careful how they are framed, who was
proposing them, which billionaire might
be funding them.
And how other advertised
that name can also be an indicator of
what's planned to do so,
climate engineering is also a term widely
used. Some say it should rather be
intervention.
And as an engineer myself, I would like
to agree because engineers usually
quite boring and have systems
that are, um.
Yeah, well understood and easy to model.
The term solar radiation management
was actually coined to avoid using
geoengineering, which was already a
loaded term.
It was later tried to replace radiation
was reflexion, but it didn't stick.
Other scientists have argued that it
could should it's not management at all
because you're not managing a process
that we don't understand completely.
It should rather be called albedo
modification or even hacking
cocktail geoengineering.
It's another example of a fancy name
was given in a modeling study to
geoengineering. Approaches were combined.
Carbon dioxide removal is,
I think, a pretty descriptive good name.
And negative emissions well.
And emissions always kind of negative.
So let's look back at
our emissions trajectory.
If you want to be really sure that we can
stay below two or even one point five
degrees above pre-industrial warming,
we should be reducing emissions much
faster.
Because if these technologies don't work,
if we are not successful at implementing
backs, then we have a problem.
So we should take more action.
It's yeah, time to do something.
But the question is what?
So in our own work, we work
a lot with the emissions data, historical
emissions and the political process.
And we try to make this as openly
as possible because without open data, we
can't judge what countries are doing and
whether we are on the right track.
We use Jupiter Notebook's and the BINDE
project to make them as, um,
yeah. Explorer and easily
usable as possible.
So go and check them out.
Here's one example.
Um, this is a Ebtekar emissions data set
which gives us CO2 emissions
by sectors.
So for Germany we see here the power
sector, transport and buildings,
buildings looks pretty much OK.
So there's at least a downward trend
visible. So it could go further.
I mean, we have positive policies as
a technology.
Transport does not really look like it's
making progress.
So we need more electric cars
and fewer cars in general.
But if you look at the statistics
from last month, we can see that there
were 300000 newly registered cars
in Germany and there were 50000
SUVs and only 3000 electric cars.
So it's really not heading into the right
direction.
And this is a political decision
that was made.
So what's Germany who prevented,
um, stricter
regulations for cars in the European
Union a couple of years ago?
And the same goes for the power sector.
We could be building, um,
wind power plants and solar panels
much faster than we do.
It's a political political decision to
not build this as fast as we can.
Here's some data from the smart, um,
platform, which shows, uh, Transport
Germany.
And, uh, a couple of days ago, we
actually met all energy or
electricity demand with, um,
renewable sources and some nuclear
energy.
So we could have switched off, um,
lignite power on the steam.
But it's a challenge.
And if we want to,
uh, reach those, unless we did, is we
need more capacity and also storage
and building such a fully decentralized,
um.
Smart grid is a very
hard task, but I
think we have to do it, and I think it is
this Congress and in past
elections, we saw great talk that
describe some of the challenges
and. Yeah.
When we'll have some more.
OK, yeah, so even if
we managed to get to 100
percent renewables, well,
we have to think about efficiency.
And I think this is also where people who
are interested in hardware and software
are coming to as these technologies
get more and more common
and popular.
But for just
as an example, with cryptocurrency,
um, they have a built in efficiency.
So we kind of have to find a way
to still stick to these kinds of
decentralized systems,
which are fascinating technology,
but on the other hand, find a way
to get.
That running without an energy demand,
that is for Bitcoin
itself in some numbers going up
to the electricity
consumption of Denmark.
A nice example of which is more like
hacking the system, hacking the social
system is the divestment movement.
So
the idea is here to to
alter the monetary flows.
So getting.
Investors persuading investors
not to invest into companies
that are carbon intensive, but to
green their portfolio just as an example.
This movement was kind of successful
recently when they when
they managed to persuade the Norwegian
government to divest
the from the
Norwegian pension fund,
all companies that
rely on 30 percent coal or
more.
But of course, as consumers,
as individuals, we are also
investors in a way, with our daily
decisions. So we should just keep that
in mind when traveling or in our
diet.
But as Robert said, there is not
one solution to the climate problem.
We probably have to think that very
holistically from the individual to
politics.
And so we also need policy
and politic political regulations
that demand from business
to to
get greener.
And just as a last example, I
think in democratic states
like ours, we are as citizens
almost obliged to protest
when we think things are going wrong.
And this just as a last example,
the end goal and the movement that now
grows from year to year where
people block lignite
mining production. That is still going on
in Germany, though, we claim to be
quite renewable already.
So.
To sum up.
To what end?
Well, we don't know everything about
climate change, but we know
definitely enough to act.
Thank you very much.
Thank you, John Accorsi,
spin room there, and the Roberts Heathkit
U.S. brands, right?
Yes, please.
Thank you for inviting us about climate
change, the climate system and the ways
to hack it. We have time for certain
questions. So if you would approach your
microphone
six. Yes, please go.
Hello. I have a question.
Do you made a calculation?
What is the real emission of electric car
in Germany? Because there are some
countries in Europe with an electric car,
in fact, is coal powered car.
And when we compare emissions
from these electric car powered by coal,
it's two times greater than the
emissions from normal gas on cars.
We don't work exactly on this, but it's
a very good question and
I agree, you need to take this into
account.
Sales, for example, the electricity map
to Iraq. We can see what the current
emissions are from a country.
So you should load
up your car when it's politics,
renewables.
Not a question.
Uh, microphone number two.
Oh, thank you.
There was a question, there was a
statement that oh point eight
watts per square meter hit the
earth. Could you see a little bit more
about this? I mean, I can see how
if you look at the whole earth together,
then the sun is always shining on one
side. So if you just can't decide that
it doesn't really matter where you look.
But doesn't it get more or less
over the years or so?
Is this like a yearly average or
what is the point? I mean,
it's a yearly average, of course.
Well, you have about 350 watts per square
meter coming in from the sun,
so you can relate it to that.
And most of that is going back out, right
back out from the thermal emission of the
earth. And ideally, you have
an equilibrium and it's
only an equilibrium over
a year and an equilibrium over
a day is not there.
And the space also is not in
equilibrium. Normally, you have a lot of
emissions during the polar night.
There's a lot of stuff going out now.
And at the same time, there's a lot of,
uh, energy coming in at the equator.
So this is actually a mean value.
Yeah, of course.
Uh, this lady here, please, should
I do so?
Thank you for your talk.
So I guess the Earth has its own
temperature changing cycles, like we had
Ice Age and stuff which were natural
climate change occurrences.
So how much do
you actually know how much of that good
old climate change is caused by man
right now?
We do have numbers for that.
Yes. Um, there's
one per parameter that is not
influenced by human humanity.
That's the sun and intensity.
So what's coming in?
And the sun has been getting a little bit
brighter if
you look at the
components that make up this time of
change. That's a very nice map in
a very nice chart in the IPCC report.
And you can see that there is,
I have to guess, but it's a few percent,
very few percent that is made up by that.
Yes. But most of that is actually
really due to changes
in the greenhouse gas content.
There's some changes in land use that's
also important.
Most of it has actually been cooling the
earth because we have been replacing
forests with farmland.
So that reflects off more.
But at the same time, we
have all these greenhouse gases coming
out from farming. So that's the main
component. Sadly, we can talk later
about that if you want.
Yes. I have to remind you as well that we
can give feedback via the farm blog.
And I suggest as well, we take
in one other question here, but
we're out of time.
We have in 15 minutes another lecture
regarding climate change.
So we were going, please shoot.
Don't hesitate, it's a I think it's
a very simple question and irony.
So we a minute
ago we talked about equilibrium state,
but what is definitely not an equilibrium
is an exponentially growing economic
economy.
And so my question is, do
you think that the climate problem could
be solved inside
or along with an exponentially
growing economy?
So because I adopted.
Well, there's
this pretty much comes down to the
question if if there is something like
green growth.
Yeah. So, um,
I personally believe.
That it's not possible
with the growth growth that we are,
that we are experienced and that
that we have experience that we are
currently experiencing to really
get to carbon neutral society.
So.
I think well, it's most often
people that are very optimistic of
technology solutions that say, OK,
we can keep our lifestyles,
we can keep on the way that we live and
that we organize society and the economy
and still get down to zero emissions.
I personally, I'm not that optimistic.
But, for example, discussions about
degrowth, for example, or a steady state
economy are not very
common in climate impact research,
unfortunately.
Mike, from number seven there in the high
back high,
you told about all the possibilities to
reduce climate change and they all have
tradeoffs and costs.
But then you brushed on animal
agriculture really quickly and
I myself can't see what's what
are the costs there. Could you please
comment on that?
You know, or do you mean like
I mean, do I believe in animal
agriculture seems to be the odd one out
in this in this series of things
you can do, because I myself can't
see any cost by just stopping to farm
animals.
All this missing, we
are, of course, not every possible
solution or a thing we can do does
have to come with the costs, but
well, of course, we kind of just brushed
through that.
That pretty much comes out, I think, down
to a to a societal discussion
of how we want to treat animals and how
our standard of living or how our what we
are used to eat is actually
how much we value that over,
for example, climate change.
Is that sufficient,
microphone number two?
Very last question of all right.
Thank you. My question
is about the climate modeling.
So one of the least crazy
skepticisms I've heard is was
by physicist Freeman Dyson, who
doubted that basically
the effect of increased carbon
in the atmosphere on plant growth
would be sufficiently modeled and
theorized that more
carbon would mean faster plant growth.
And regarding the feedback
loops that were mentioned would be one
example of a of a dampening feed,
a feedback loop, rather
than a reinforcing feedback
loop.
Yes, that's true, that's one of the
feedback loops and it is modeled
their are papers out there that actually
measure plant. They put plants on a
little greenhouse and put CO2 there
and measure how fast they grow.
And the part that was missing
from the 90, 97 percent
that went into that went into the ocean
so far is supposed to be taken out
probably by the biosphere.
We're not sure.
So this is included in the model.
The question is how?
Well, it is included in the model.
These and
insecurities, these
unknowns always create a bit
of an error range. So what you usually do
is you put the bottom parameter and you
put pyramiding and few in between maybe,
and you see what happens.
Um, but yes,
we're working on that.
It's just not enough as far as we
see is not enough to offset the problem.
Oh, there's a talk about that later.
I just heard. OK, thank
you. Please give us a warm
applause, these researchers.