 give a warm applause for Dr. Benjamin Leo Bordersky, a doctoral researcher at the Potsdam Institute for Climate Impact Research, and he's designing quantitative computer models and global nitrogen cycle simulation. So it's like civilization ate, nor was more realistic. And what we can learn from it and how we can use it, you will hear now. What we are doing there is we are doing computer simulations of all kinds of sciences, from natural sciences to social sciences. But this campus has actually a long history already of science. So it used to be the astrophysical observatory and the meteorological observatory. And quite a few experiments were carried out there. So there was the G-value measure, the value of gravity. The first earthquake was recorded or some equations of the relativity theory of the fields equations were solved in this former institute. Since 1990 now it's the Potsdam Institute for Climate Impact Research. And what you can see nicely here at these buildings are still the old cupolas which used to have inside large telescopes. And these telescopes are a bit a symbol for the first scientific revolution, the first Copernican revolution, which happened about 400 years ago. And this scientific revolution was sparked by the technical development of lenses which allowed you to use microscopes or telescopes. And these opened up a new field of research because suddenly you could see things which were quite small, even larger. You could see things in detail and you suddenly had a view inside the huge complexity, both inside a cell or inside of our universe. Some scholars argue that today now we are living in the second Copernican revolution and this second Copernican revolution is triggered by the development of so-called microscopes. Probably nobody of you ever heard this word because it's invented. Hello translators. But maybe you can think what it means. It's kind of the inverse of a microscope. Instead of showing you things in more detail, actually it does the reverse. It shows you things in less detail. It reduces the complexity of the real world. And this is something that is really necessary because the complexity of the real world is sometimes overwhelming. And if you want to make decisions, we sometimes need simpler versions of the real world to understand them. So how can a microscope look like? Well, the first approach is quite straightforward. If you want to see something in less detail, you just go one step back or two step backs or even further. So one option is a satellite. If you look from a satellite on the Earth, you can see the macro development on the planet. And, well, things that you can see is first of all, the Earth is quite a beautiful planet, but you can also see what's happening on the planet right now that streets are going into pre-steined forests, that we are burning down forests all over the world, that at night time the Earth is still illuminated by electric lights from the cities. And you can see how strongly we already shape the way the planet looks like today. You can clearly see that we are now living already in the Anthropocene. A second option to see the Earth system in a reduced form is you can rebuild it in a smaller scale. This has been carried out in the 1990s with the Biosphere II experiment. It's basically a whole Earth system in a glasshouse, in a confined glasshouse which has an ocean, which has a rainforest and desert and also eight human scientists living within. And you can see it as a successful failure in the way that after a very short time already, the whole ecosystem collapsed, the fish in the oceans died, the ecosystems were run over by cockroaches and ants, the CO2 levels rose extremely, and the scientists which were basically confined in this were getting quite hungry and towards the end of the experiments they actually had to import food from outside of the system. So it's not as easy to rebuild such an Earth system and actually we can be happy that we are living in such a stable one as we have currently on the planet Earth. Now the last, the third option of reducing complexity is we put the real world into a set of equations, a computer model, and use this computer model to simulate the Earth system. There's a clear advantage of this. First of all, it's quite cheap. So you can repeat it. You can do several, well, thousands of simulations. And of course in reality we only have one planet, right? So we can only carry out one experiment and that's the experiment we're currently living in. So there's no option to repeat it if we fucked up the climate or something else. Sorry. So this has been the first computer model or the first widely known computer model. It's the World 3 model from 1972, known by the report the limits of growth of the Club of Rome. The basic message was that if you have exponential growth of the population and exponential growth of the economy, while you have limited natural resources, there will be one point where the social system collapses, where the population is going down up to a level where the planet can sustain it again. Of course, this was one of the first computer models. It was really simple. It was also heavily criticized for being oversimplified and luckily for us those projections didn't become true. But it already shows by triggering quite a big debate that it was quite a useful computer model because suddenly we were thinking long periods forward and of course we did not stop with this one computer model but we continuously further developed it. So this was 1972, 35, more than 35 years ago and since then of course computers became much more powerful and of course also some a bit slower technological progress in the science community happened. So we are still on the challenge of making good simplified computer models. Of course they are wrong. That's what a model is always because it's simplified. It leaves out processes that are important but they are useful for us for decision making. So at Potsdam Institute we have quite an ensemble of different models. Here you can see for example climate models feeding information to a vegetation model which calculates carbon stocks and natural vegetation, crop yields, hydrology and so on. Then we have information from such a vegetation model being handed over to a land use and agriculture model which is the model called McPy and then we also have a macroeconomic model and energy model which simulates the development of the industry of the service sector of the energy sector and of course also always the greenhouse gas emissions. I want to focus today on the McPy model. McPy stands for model of agricultural production and its impact on the environment. This is the model I'm working with. It's developed by a large group of approximately currently 15 people of various scientific backgrounds. So we have economists, we have physicists, we have biologists, geologists and so on. And the basic question that we want to answer with our model is how will the agro food system look like in the year 2050 and beyond? Why is this important? Probably for you agriculture is not so important. Hardly anyone still works in agriculture but for our planet agriculture is really important. It's our main interface with the nature. If you look at our planet 30% of the terrestrial surface is covered by agriculture either by cropland or pastures. If you look at greenhouse gas emissions 25% of the greenhouse gas emissions come from land use change and agriculture. So again, struggling with agriculture. If you look at water 70% of human water withdrawals are for irrigation water. If you look at water pollution at herbicides, at biodiversity always there is agriculture as one of the major drivers. Also we are now really changing the nutrient cycles of the world, increasing for example the nitrogen cycle by factor 304 relatively to earlier years. And there's also another thing of course agriculture is also really important for us humans because we can live without energy. We can't live without food. And if you look at the global 19 leading risk factors worldwide for preliminary death 11 of them are connected somehow to nutrition. So either we eat too much which is red or too little which is green. It's something like iron sink deficiency, vitamin A deficiency, suboptimal breastfeeding. But on the other hand there's also a lot of things connected to unhealthy diets like high blood pressure, high blood glucose, overweight and obesity. On these top 19 you cannot find wars or terrorism or something like that but it's really about mostly about chronic diseases and most of the chronic diseases are strongly connected with our daily diets. So how does such a model look like? Basically we start off with the food requirements. What do people actually eat? And what do they actually need as food to sustain their body functions? Well this of course depends on how large the population is and what each of them eats. At the moment we are already at a world population of 7.6 billion and we're still growing. We will most likely be 8.5 to 10 billion people in the year 2050 so then we need to do some more re-fragmentation here. And eventually afterwards there is an option that it might decline or further increase and this depends a lot on education and on family planning. At the same time what people need to sustain their body functions per capita is quite always the same actually. There are some differences depending on demography. You can see that Africa has a lower requirement because there are a lot of young kids in contrast. In China a lot of young adults you have high food requirements but of course this will shift as soon as we have demographic change in the future and then we will have in contrast high food requirements in Africa per capita. But in general the range is really low. 2000 to 2300 kilocalories per capita per day in population average. But this is of course what the people would require what they actually consume is much more. So you can see in Germany we have 3500 kilocalories. In India it's closer to the food requirements of 2450. But you can also see not only that there is a lot of over consumption you can also see that the diets are quite different. In Germany we eat quite a lot of animal products which people in Nigeria or India don't and we actually don't eat too much fruits and vegetables which is a shame for us. But you can see that we consume about one third more than we need and what's the reason for this? Basically it's that we waste quite a substantial fraction of our food. About 30% of the food gets wasted in households just because people don't care too much about it. And you can see quite strong correlation. So as soon as people increase their living standards as soon as the human development index increases you also see that the food waste is starting or the over consumption. This also includes over consumption in the sense that people eat more calories but also there the window is quite narrow. Most of it is food waste. And the same you can see for per capita calories or the share of livestock products. You can see that the share of livestock products strongly increases with income. On the left you see just a scatterplot between income and the livestock share for all countries of the world for the last 50 years. And you can see that countries strongly increase their meat consumption especially when they move from very low incomes to medium incomes. For very high incomes eventually the livestock share declines again. And you see the same actually also for processed foods like oil, sugar consumption goes up. Unfortunately you don't see it for fruits and vegetables which would be healthy but there it saturates quite as an early income. And then of course these food, the food demand has to be satisfied by production. Before that there's some trade, international trade is increasing over the last decades quite strongly much more than production. And next to food demand there's also the demand for materials but also for bioenergy which will play a role, an increasing role. I don't know if you heard the talk before which may play an increasing role in the future if we want to mitigate climate change because bioenergy is one option to take CO2 emissions again out of the atmosphere. And then food is of course also processed and here the livestock products really play a huge role because in order to feed one or in order to produce one calorie of livestock products you need multiple plant calories to feed the animal. At the moment approximately half of the proteins that are produced worldwide on the crop lands are fed to animals. And additionally also even larger quantity of pasture which is grazed by animals. And finally we have crops and these crops are standing on a land. And here you can see some land use dynamics. Here you can see a projection or scenario for a future scenario of how the crop land might expand in the future. Quite strong expansion especially in the tropical areas because they are also the population growth is largest. And next to land use this also well on the one hand you have crop land expansion but this is not the only option of course to increase production. In the past this made up only 10% of the increase of production. The largest increase actually came always from the intensification of the existing areas. And here you can see basically the crop yields that we would need in the future in order to fulfill the demand. And finally our model also considers all the interactions with the biochemical cycles. So how do we change the nitrogen, the carbon, the phosphorus cycle, also how will water scarcity change? This is a picture where you can see the water scarcity in 2010 and 2050. So it's basically not the water scarcity but how much of the water that is available will be under use. And the nitrogen cycle as the third most important biochemical cycle of the world has been changed tremendously by modern agriculture. We are now about five times the amount of nitrogen which flows through the cycle then in pre-industrial times. And finally we end up with emissions. And well if we assume a scenario where we don't take action we can assume that we simulate that the emissions will further increase while actually in order to keep or stay below the two degree aim we would actually need the land use sector to sequester carbon. So we need to take CO2 out of the atmosphere. This is something that only the land use sector can provide at low costs either through afforestation, through plantation of biomass or through accumulation of carbon in soils. So this is the whole integrated model and the great thing is that well it's an optimization model where everything influences everything. So if you put a carbon price in this will change the whole supply chain. It will change the food demand. It will change the global trade patterns. It will change the land use pattern. If you can also see the interactions for example between the nitrogen and the water cycle or how well but you can also see quite well the trade offs that exist in our earth system. So if you only want to solve one specific aim it's still well quite easily possible. But as soon as you have multiple goals for example if you want to provide enough food for the whole world population this will also require you to increase your food production and then you will have the environmental impact. If you want to reduce greenhouse gas emissions you will need bioenergy and this of course also has negative impacts again on biodiversity, on food consumption, on food prices and so on. So it's a very complex system and it's really a challenge but it's possible to transform our society sustainably that we actually meet all these goals at the same time. What's really crucial there is on the one hand the consumption side. So we really need to reduce food waste and we need to reduce the consumption of animal products by large scale. So having animal consumption, having the food waste in Western society would be something that we should aim for and this is really difficult. At the same time the whole production system can be much more efficient. A small price on carbon would be sufficient to trigger off technical innovations probably and to implement low cost carbon mitigation technologies. But these are probably the two things that we need most. We need a policy that puts prices on emissions, on carbon, on nitrogen, on water pollution and we need some kind of policies that change the preferences of the people in a way that they, for example, education, school education for what is a healthy diet, how do you cook at home and so on. All these kind of projects have to be really encouraged. So what can you do? Well, one advice I would want to give out is get involved in modelling. Most of us are actually, well, we're not computer scientists from the beginning but we have to learn quite a lot of this but we are rather coming from disciplinary backgrounds, economists or biologists or something like that. But most of our time is actually software development. And it's not that we don't want software developers, it's just that few people actually apply there. So I think putting up the standards of software development in the whole field would be really a great thing. The second thing is there's a lot of data out and there's a lot of, well, also great science that could be communicated using good visualisation techniques, using also maybe artistic projects and so on. Just want to give you one example before I come to the question and answer. Here in the last year we made a workshop with art students who developed interactive installations using our data. For example, here it's an audio installation where people could hear the sound of different scenarios depending on whether it's a scenario where all the forests are cut down then you have rather agricultural sounds or more urban sounds in another scenario. Or maybe I'll just pick one more because we have limited time. This is an artwork by a student from Bangladesh and she created a climate box. You can enter this climate box, throw in a coin and then using an Arduino it all starts moving. You get told the story of climate change but at the same time also the weather in the climate box is changing so suddenly it becomes hotter and there's a fan blowing in hot air and suddenly it starts raining and there's flashlights and then if you don't spend more money on it then it becomes even worse and worse and worse. This artwork was actually inspired because she said people back home see climate change as something abstract but as long as they don't feel that they wouldn't do something so she came up with this idea. Now I'm ready for a question and answer. Thank you very much. Everybody with questions please go to the microphones in the room and internet over the signal angels. So microphone one please. Oops, it's charged, I got electrocution here. Thanks for the talk. One question, when you looked at the needs of people you spoke about calorie requirements. However, nutrition is much more than calories especially not in Germany but in the Sahel area when you further reduce the animal protein part you get problems with malnutrition. Is that something you factor in or it's just plain calories and you eat sorghum with sorghum? Of course dietary diversity is really important. I would not say that animal protein is the only way of solving this because you can have a balanced diet also without animal protein but it's important actually one of the most important challenges is to drive up the consumption of vegetables and fruits by several factors and there's hardly any positive limitation especially for vegetables to the health impacts of higher consumption of vegetables and fruits. Of course we look at the dietary composition and there we also don't only look at livestock versus plant calories but also now on fruits and vegetables and on processed calories. But yeah of course I think it's a major problem that we should not play out goals like food security against goals like climate change. We need to simply tackle both of them and as urgently as possible. Thanks we have five minutes so next microphone number two please. Sorry I think I'm too small for this one. Okay so I've got two questions. You were talking about trade-offs. So what would you think is the best solution to the crucial trade-off between biodiversity and land conversion for food security? And the second question is you were talking about how important is that we invest in societies to drive up our vegetable and fruit consumption but this again would mean that we shift the land usage for high calorie foods even if they are not dairy or livestock in any way. So that again we use more land and this again would cause more rivalry between global food users. Isn't this contradictory to food security and aren't we quite healthy already if we stopped eating sugar like crazy? Thank you. Okay I forgot the first question again. What was the first question? The trade-off between land conversion and biodiversity. So there's certainly a trade-off between those two but as I said before in the past only 10% or the cropland in the last 50 years only increased by approximately 10-11% and all the rest of the productivity improvements were actually reached on the area. At the moment there are quite large yield gaps in wide areas of the world where you could actually intensify and where it would be actually good to intensify the systems to a certain degree and without any land expansion actually necessary. There are certain areas where I guess land expansion is possible. It's always a trade-off of course and we are trying to build in exactly this trade-off by now including biodiversity indicators in our model but this is still work in progress. To the second question on the fruits and vegetables fruits and vegetables actually make up only a tiny share of current land use I think less than 10% definitely and at the same time they are producing quite high yields because it's not the land which is the main resource there but it's labour which goes in and capital. It's not necessarily a clean production either because you have large nutrient run-offs often large pesticide use but in terms of land use it's not such a bad thing they make quite high tons of produce out of a vegetable farm but of course there are also trade-offs here there's a sustainable probably sugar is providing really cheap calories without large environmental footprint if you calculate it per calorie in contrast fruits and vegetables provide very little calories but provide a very nutritious food in terms of fiber, vitamins and so on. We have a lot of question I see eight and one from the internet we have just two minutes so I take one from the internet one from five and I ask everybody else to ask the speaker afterwards he is here and he answer all your questions so internet what is your question? Okay, so as he asks how do I get involved in modeling can I play with Magpie by downloading code and data somewhere? Hello internet the model will become open source next year so we are currently in the process of the whole legal stuff of making it open source so the next model version of our model will be published open source. Microphone five please. Hi, thanks for the great talk. Last year there was also an awesome talk about plant-based food innovation that is science-based so my question is twofold first, do you implement technological innovation that would lead to a more plant-based diet and in general in the model and the second one how hopeful are you personally that those will have an important impact in the future? You are speaking now of some kind of plant-based meat replacement products and so on yes we actually published a study or a commentary this year also on a quite extreme case of this which is basically land less food production so you can read microbes based on fertilizer and energy it's kind of a space food technology it was developed by the Russians now it actually becomes commercial cheap I guess it will certainly happen for certain protein foods so it will for example replace soybean or fish meal in animal feeding to a certain proportion I'm not so sure about the actual nutrition value of this or about well I'm a bit skeptical how positive I would judge it but I would judge it quite realistic also for the whole meat replacement products based on plant-based on plant basis I think it will become economically just cheaper and then you will have a tipping point where simply because of economic reasons it's cheaper people will reduce their meat consumption or for example a burger will consist of half fake meat and half real meat because it's cheaper and I think this transformation will happen somehow the breeding animals just for for their meat seems a technology which is somehow outdated for the 21st century if you ask me then give more than a big applause to Dr. Benjamin Leon Bodewski thank you