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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 máxima 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 o
f 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. A
nd 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 al
ready 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 differe
nt 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 thi
ngs 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 b
ecause 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 diffi
cult, 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 req
uire, 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 t
echnological 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 he
re 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 fasci
nating 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 calculatio
n? 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.
