Minecraft anarchy – A hacker’s guide to Climate Change – What do we know and how do we know it?

Okay second attempt for this advertisement stream for there’s a good event um yeah let’s go lazy google land is reachable under lga.com.com it’s a anarchy server in vendor so there are no plugins there’s no entity cheat and what was i about to do oh start the machine and i killed it

i killed it that is really not good i should use dirt anyways instead so this is a server where you’re allowed to use cheat clients where you’re allowed to kill other players and you’re allowed to breathe and all the other nasty things and why was that not even surprisingly

You know what me let’s go just with one oh yeah let’s go in the wrong direction sure why do i suck so much so this stuff is all about you know playing manila without rules without admins do what you want things like that and there are no words

Resets there are no plugins there no admins there’s no administration there are no pens and um yeah and there are also no players so come and join play with me and i’m now going to play like a video from the media.ccc.te channel it’s from uh from 2017 it has a title 34

C 3 a hacker’s guide to climate change but we know and how do we know it a hacker’s guide to climate change sounds kind of familiar but i mean i i couldn’t like prove that i’ve seen it already anyways um oh cool i’m not even muted so

You actually can hear what i say that’s so convenient anyways i would say let’s get right into it and yeah so if you’re interested in the talk go check out the description where i have a link for you um linking the original video other than that i would say let’s get

Right into it Uh welcome kate or so i say say who say you all right um i’m having the honor and the pleasure to introduce you three people here for the first lecture and say who will start she is a phd um doing a phd concerning environmental or physics in which university

Heidelberg all right um i noticed here that for some people climate change seems to be just news that’s passing by for some others it’s a little bit more fake news someone this morning called it even 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 akopolis um the word is to you please give her welcome applause Hello everyone is this working hello hello can you hear me oh fantastic i was just not used to that okay um 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 uh surroundings everyone is working with us we know a lot of this 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 uh 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 um what are the basics we have two 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 it with each other with each other apart from electromagnetic radiation you can see here there is a a lot of distance between the two and the only interaction possible is light

What is light about um 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 um there’s a large maxima in the visible

Visible part in 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 this long tail that’s infrared light you can feel as warmth and on the short la is short side there is a bit of infra 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 is 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 spectra that’s been taken on the iss 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 form before it’s this form um it’s given by planck’s law planck’s planck

Found this law in about 1900 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 as some radiation going off and if it becomes warmer you put something in the forage it radiates off more energy so this is the relationship i put the formula in 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 is simply it’s simply inverse to temperature and as you can see here there’s a body 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 i miss i did this in python and uh i mis typed a little so it’s close enough it’s fine

Um you can see here that you can see nothing let me scale that up um 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 uh almost no overlap between those two spectra so the radiation coming off the sun and the radiation coming off the the earth they are very very different in energy why is this interesting um we can now calculate the temperature

The earth would have it if it was just like this simple energy uh equilibrium um there’s another parameter we need because the uh planck spectrum the 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 radio out of heat and you can imagine that the uh wavelength they will radiate off if they didn’t have internal energy whatever will be different so earth

Has an albedo of about 0.3 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 at 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 it just think about what should we do to change parameters of the system to to change what’s going on so here’s one one chance we have um 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 law here that’s been found by lambert and bear two different people he 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 l it depends on the density of the gas so how much how many

Molecules of the gas are there it’s rho 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 it changes 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 this in your lab if you want or in the hackerspace or whatever it’s really easy so are the consequences of this i brought you a picture of no2 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 the wavelength wavelengths you can see as you can see there’s a lot of absorption going on in the blue wave range wave range 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 gas is

Or you should be able to do that now you can say it’s reddish 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 a hundred percent of light coming in from the top it uh goes down to the atmosphere thirty percent as i said before is already reflected back so this does not concern us at all unless we want to change it but yeah um and 47 are absorbed by the ground

The ground heats up you can feel this 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 uh about 12 percent can make it through of the of infrared light the

Light with a lower wavelength with a with a very long wave range 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 the at the wavelength the gas absorbs it’s also going to emit i’m going to show you later um this effect also stacks 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 a part will go back down and in the end you get a mean uh

Radiation level of about 97 of the incoming sunlight going back down so about twice the level of the sunlight that reaches the ground um 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 144 of the light are actually radiated out so the uh blackbody temperature that you get at the earth is higher than it would be without atmosphere we get 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 black body 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 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 natto and so the difference between the plots is the 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

Um 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 let me see that 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 0.8 watt per square meter of energy coming in that’s not going out here’s 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 mean temperature of 15 degrees and you can see um in the in the outgoing radiation here the 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 air is minus 30 degrees so in the stratosphere already maybe top of whatever

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 -55 degrees so you can see here which height the light comes from

And at which layer the air is transparent for this uh wavelength ranges i’m sorry if this is a bit complicated um 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 noah yesterday you can see that they have a continuous record since its 1960s to today and their current level in september was 402 ppm parts per million and you can see that it’s 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 respirate more in summer than winter so you can actually see the plant level the plant life here okay so what do we do with this

We can run a very simple calculation from what i showed you before you know know 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 1.2 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 cannot melt ice change the albedo of the earth it can generate more clouds there’s more

Energy more water can be evaporated more clouds can be generated it changes the albedo it changes the uh outgoing energy um level and the temperature gradient changes there’s a lot of feedback mechanisms and we come to a result of about 1.5 to 4.5 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 see you next talk 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 0.8 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 those 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 this result that we have an energy

Overlap energy over too much energy so um 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 conclusion the upper layer of the ocean

That’s the top part warms up the lower layer the deep ocean also warms up that’s the lower plot so this is where the energy goes so far here’s 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 dissolved 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 uh 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 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 uh if you’re not convinced by this yet i have more plots i’m not going to discuss these in 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 sea temperatures and sea ice c temperatures sea content and the snow and ice are also there and you can see they all agree we have two data sets a 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 very very 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 parametrize 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 or incoming light a little there’s clouds

That can change there’s 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 chaotic system here it’s clear however that we have this energy um 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 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 [Applause] [Applause] okay yeah like i i said we know fairly well about the greenhouse effect and well with some confidence we can also project the temperature on average um 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 managed 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 katja said the mechanism there is not fairly 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 will melt snow and ices especially in the glaciers on greenland and on

Antarctica so knowing the temperature we can also project quite well the mean sea level rise that we are 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 manage below that but all these

Things that we set in motion there the melting of the isis is actually quite slow process so even after 2900 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 okay sea level rise um 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 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 the relation

To the annual average temperature there so in there they count 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 u-shaped uh relationship between those two so well okay if we know the annual average temperature how does

How that affects the the the um the gdp per capita um they said okay let’s try to extrapolate that and if we extrapolate that they find that well regions that are um already warm kind of like beyond the the curve even go down in 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 onto economic activity and if you can really extrapolate that under climate change we don’t know yet another very important number that is discussed in

Climate economics is the so-called social cost of carbon because we might ask well if we emit an additional ton of co2 or another greenhouse gas what damages does that does that mean along the road so if you think of a simple coupling of an economic and the climate model

We can say that okay 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 um every temperature change might um 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 ton of co2 in there how many damages do we get additionally along the road in a formal way that looks actually like that so

If we emit an amount of carbon at the at t no 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 sum that up but what is done in economics or 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 euros for tomorrow so you you’ll value these 10 euros tomorrow more than those in a year this is so this de-evaluation 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 um the famous model dice 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 the social discount rate in here which is normally used with 1.5 in that model so that means you kind of gray out the future in a way from the symbolic point of view yeah so we care more about the damages here than here but if we increase the social

Discount rate these graying out goes 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 uh one or two decades to come well 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 we don’t value the damages along the road as much as the damage is 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 we stick with 1.5 social discount rate we start with 20 per ton and up to over 100 in 2100 the peculiar thing about that is that the u.s 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 number 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 in average around 45 dollars per ton now the trump administration which has kind of a different goal there um decided to have well a social disconnect 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 question of how much do we de-evaluate the damages that

Future generations will have to cope with in comparison to the damages that we have to cope with okay still this is a very simple economic model and with a very simple climate model in there so it 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 hurricanes is still going on if they get more frequent or more intense but as katya explained to you due to

Climate change we’ll have more energy in the whole earth system and so we’ll probably get also more energy in the hurricanes especially since they feed from the from the water 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 ocean is 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 grid that the u.s hurricane center uses well you probably also heard about other kinds of impacts

Which are floods and droughts and also here 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 this placing 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 under additional pressure so societies that are already prone to um ethnical rights for example 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 okay how why do we care why do we care in europe

We might be able to cope with um with floods because we’re rich in comparison to the rest of the world 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 is 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 you’ll also suffer from damages you can hear me great okay so next let’s have a look at global emissions so this is 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 in grey we can see the range of projected emissions from the climate action plans of countries so these climate action plans or nationally determined contributions

Short ndcs are part of the paris agreement process and each country individually determines what they want to do to reduce their emissions and the range is so wide because each country makes their own plans and they are difficult to assess some countries might might rely on economic growth for example

One country might only give out um a target that they are very sure to reach another country might have difficulties reaching it for example germany is not even on track to reach their 2020 goal and if you compare the this range with um The range that would be required to stay below 2 or even 1.5 degrees we can clearly see that we’re not even close to that so in green and biology you can see these ranges so what should we do maybe should we start hacking the climate if you’re not reducing emissions fast enough

Geoengineering is 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 wyatt or dash beagle and also the ngos published warning reports and um of course the scientists also published many studies and yeah

So why is it important to talk about geoengineering and removing emissions from removing carbon dioxide from the atmosphere they’re practically part of all scenarios that are used to assess our chances to stay below two degrees so here’s one stylized scenario the red line is the emissions pathway and the brownish Area shows the co2 emissions and emissions from other greenhouse gases and below the zero line in blue we see emissions that are being removed so negative emissions and if these negative emissions get even larger than what we emit as you can see at the end of the century

Then we are might even be reducing co2 concentrations in the atmosphere again so how can we do that one easy way is to simply plant lots of trees for a station and make sure that these trees never get cut off or burn another more technical approach that is

Part of all these scenarios or of most of the scenarios is a technology called bags and bags stands for bioenergy with carbon capture and storage and it basically means producing biology as we all are already doing so planting crops or fast growing woods and then transporting these biomass

To a power station burning the fuel and capturing the carbon that is released again in the burning process and then storing this carbon in geological storage size deep underground so this sounds like a great idea and if you think it’s true it means the more electricity you produce with um

With specs the more c2 you move from the atmosphere so if you were driving a car um that would be powered by electricity from backs the more you drove your car the more um you removed 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 this can be up to the size of one or two times of india so you see india over europe and it’s clear that having so much additional land use and farming land required

Would not be without problems so there would certainly be competition with food production so potentially rising food prices and it’s not easy to produce such large amounts of bioenergy without heavy fertilizer usage and then potentially using biodiversity loss and all the problems that we already have with sustainably producing things in every

Culture another problem is that we need to move all the biomass that we need to the power stations and then we need to transport the co2 that we captured to the sites where it can be stored so that would require building a huge um 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 and now already in germany there are um in some federal states it’s there are laws and regulations against having such sites because nobody wants them

So carbon dioxide removal like max is a technology that directly works or attacks the the main main cause of climate change so reducing carbon emissions there exists other geo engineering ideas that work more against the impacts as we saw and one of these is solar radiation management and more specifically

Stethospheric aerosol and injection and the idea here is to mimic what happens to a volcanic eruption and to as we saw on the first part from katja to reflect back um incoming sunlight so that doesn’t reach the earth of course with a volcanic eruption then this the reduced temperature is gone after a

Couple of years so we would have to artificially using airplanes bring small particles into the stratosphere and do this basically forever this also points to the 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 feel masked and prevented by this technology would then quickly be added to the warming we got anyway and it seems certainly bad to have a fast termination shock like this and a slow gradual temperature rise another problem is that

Who gets to decide about the optimal global temperature it could be that in some northern countries The people would accept a higher temperature and some people in a low-lying island that’s not by sea level rise they would rather want 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 here uncle scrooge wanted to profit from a volcanic eruption and install large 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 in this story it didn’t turn out so well but in fact real scientists in the last years have looked what it would take to pump

Water back onto antarctica and let it freeze there again to prevent sea level rise another study looked what it would take to rebuild the arctic ice and both studies used 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 fourteen 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 is proposing them which billionaire might be funding them and how they are advertised and named can also be an indicator 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 engineering is usually quite boring and done to systems that are well understood and easy to model the term solar radiation management was actually coined to avoid using geoengineering was which was already a loaded term it was later tried to replace radiation

With reflection but it didn’t stick other scientists have argued that it could should it’s not management at all because we’re not managing a process that we don’t understand completely it should rather be called albedo modification or even hacking cocktail geoengineering is another example of a fancy name

This was given in a modeling study where two geoengineering approaches were combined carbon dioxide removal is i think a pretty descriptive good name and negative emissions well aren’t emissions always kind of negative so let’s look back at our emissions trajectory if we want to be really sure that we can stay below 2

Or even 1.5 degrees above pre-industrial warming we should be reducing emissions much faster because if these technologies don’t work if we are not successful in 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 emissions data historical missions 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 notebooks and the binder project

To make them as explorable and easily usable as possible so go and check them out here’s one example this is the edgar 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 okay so

There’s at least a downward trend visible so it could go further i mean we have passive houses as a technology transport doesn’t really look like it’s making progress so we need more electric cars and fewer cars in general but if you look um at the statistics from last month

We can see that there were 300 000 newly registered cars in germany and there were 50 000 suvs and only 3 000 electric cars so it’s really not heading into the right direction and this is a political decision that was made so it was germany who prevented stricter emissions

Relations 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 decision to not build this as fast as we can

Here’s some data from the smart platform which shows transfer germany and a couple of days ago we actually met all energy or electricity demand with renewable sources and some nuclear energy so we could have switched off lignite power on this day but it’s this challenge and if we want

To reach this on less windy days we need more capacity and also storage and building such a fully decentralized smart grid is a very hard task but i think we have to do it and i think it sees this congress and in past versions we saw great talks that

Described some of the challenges and renewables well we have to think about efficiency and i think this is also where people who are interested in hardware and software come into as these ict technologies get more and more common and popular but for just as an example with cryptocurrencies

They have a built-in inefficiency 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 um from the norwegian pension funds all companies that rely on 30 coal or more but of course us 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 um to get greener and just as a last example i think in democratic states like ours we’re as citizens almost obliged to protest when we think things are going wrong and this just as a last example

The ending lending 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 and well we don’t know everything about climate change but we know definitely enough to act

Thank you very much Please um thank you for enlightening us about climate change and climate system and the ways to hack it we have time for certain questions so if you would approach approach your microphone um six yes please go hello i have question do you made calculation what is the real emission of electric car

In germany because there are some countries in europe when electric car in fact is coal powered car and when we compare emissions from this electric car powered by coal it’s two times greater than the emission from normal gasoline 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 there’s for example the electricitymap.org where you can see what the current emissions are from a country so you could should load your car when it’s powered with renewables another question uh microphone number two oh thank you there was a question uh

There was a statement that um 0.8 watts per square meter hit the earth could you say 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 discount the side then it doesn’t

Really matter where you look but doesn’t it get more and less over the years so this is like a yearly average or what does 0.8 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 uh a year and in equilibrium over a day is not there and

The space also is not an equilibrium normally you have a lot of emissions during the polar night there’s a lot of stuff going on 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 good uh this lady here please shoot hello so thank you for your talk um so i guess the earth has its own uh temperature changing cycles like we had ice agents stuff which were natural climate change occurrences so how much or 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 uh one parameter that is not influenced by human humanity that’s uh the sun and intensity so what’s coming in and the sun has been getting a little bit brighter um if you look at the

Components that make up this climate change there’s a very nice map in a very nice chart in the ipcc report and you can see that there’s 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 forest 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 sally we can talk later about that if you want yes you have to remind you as well that we can give feedback via the fireplan um and i suggest as well we’ve taken one other question here but uh we’re out of time we have in 15 minutes another lecture

Regarding climate change so we were gone please shoot uh don’t hesitate it’s a i think it’s a very simple question in irony text um so we a minute ago we talked about equilibrium state but what is definitely not an equilibrium is an exponentially growing economy 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 it well this this pretty much comes down to the 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 expect that we’re experienced and that that we have experienced that we are currently still experiencing to really get to carve a neutral society so i think well it’s most often people that are very optimistic of technology solutions that say okay 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 am not that optimistic but for example discussions about degrowth for examples or a steady state economy are not very common in climate impact research unfortunately

Mike for number seven there in the really high back uh hi um you told about all the possibilities to reduce climate change and they all have trade-offs and costs but then you brushed on animal agriculture really quickly and i i myself can’t see what’s what are the costs there could you please comment

On that or do you mean like i mean animal agriculture seems to be the odd one out in this in this series of things we can do because i can’t i myself can’t see any cost by just stopping to farm animals yeah of course not not every possible

Solution or a thing we can do does have to come with the costs but um well of course we kind of just brushed through that um that pretty much comes out i think down to a societal discussion of how we want to treat animals and how

Our standard of living or how are what we are used to eat is actually how much we value that over for example climate change is that sufficient okay um microphone number two the very last question right yeah uh thank you my question um is about the climate modeling so one of the

Least crazy uh 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 there are papers out there that actually measure plants 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 the 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 um these and insecurities

These unknowns always create a bit of an error range so what you usually do is you put the bottom parameter in you put club parameters 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 it’s not enough to offset the problem and there’s a talk on that lighter registered okay thank you uh please give us a warm applause these [Applause] Researchers So that’s it for this advertisement stream i hope you check out laser working and we can play together awesome bye i