Thanks for tuning into my talk. My name is David Meintrup. I'm P rofessor at Ingolstadt University of Applied Science. Today I'm going to talk about the Earth, the climate and you.
Let's start with a warm up talking about the climate, no pun intended. Please consider these four actions. Imagine you would keep doing these for one year. No plastic bags, go vegan, drive fuel- efficiently, or always switch off stand by modes. Can you order them by the amount that they reduce your carbon dioxide footprint? No? Well, don't worry, you're in good company.
A study that was performed by A.T. Kearney i n 2019 came to the conclusion that we generally have no clue what reduces our personal footprint. They gave people seven personal actions, from no plastic bags to one flight less per year to region and season food, et cetera. You can see what people thought, their answers on the left side. I will give you the correct answers at the end of my presentation, but I can already tell you that people were completely wrong.
I stumbled across this study a year ago, and I will openly admit I had no idea either. But how are we going to save our planet if we don't know? This was the motivation for today's presentation.
I'm mathematician by education, and I've been promoting statistical literacy for many years. There's this famous quote, "Statistics is too important to be left to statistic ians and I think that the same is true for the climate. We need climate literacy to know and understand the Earth's climate, impacts of climate change, and approaches to adoption and mitigation.
In the same spirit, I would like to say climate change is too important to leave it to climatologists. And despite the fact that I'm a mathematician, I wanted to study the topic and talk about it. In one sentence, the goal of my presentation today is to increase my own and everybody else's climate literacy.
I would like to do this by answering three questions. Why exactly does climate change happen? Since when do we know? And what can each and everybody of us do about it?
Let's start with another question. Did the average global temperature increase? Yes, no, or one can't say? Well, as you all know, the answer is obviously yes, and that is not difficult to prove as one can simply measure the temperature.
H ere you see the development of the global temperature over the last 140 years. C ompared to the reference interval from 1880 -1910, we have an increase of approximately 1.1 degrees Celsius. In addition, it took only 30 years to double the increase from 0.5 degrees to one degree.
Next question, what causes global warming? Well, again, I guess that you are all familiar with the answer. Carbon dioxide emissions from burning fossil fuels like coal, oil, and gas. But do you also remember why? Why do these emissions cause global warming?
Well, the answer is the greenhouse effect. And I would like to present a few more details on that. The temperature on Earth is completely determined by the radiation balance. We have incoming solar radiation that is partially absorbed and partially reflected by the Earth and the atmosphere. From the absorbed energy, one part is radiated back into space as heat, and another part is absorbed by greenhouse gasses and then reemitted down to the Earth. And this part is actually what is called the greenhouse effect, and that is causing the global warming.
Now, which gas contributes most to the greenhouse effect? Is it water vapor, carbon dioxide, methane, or ozone? I guess that most of you will have answered carbon dioxide, but actually it's a trick question. Because the trap here is that I didn't ask about the manmade greenhouse effect.
Let's have a look at the details. Greenhouse gasses actually keep us warm. Without atmosphere and therefore without any greenhouse gasses, the temperature on Earth would be on average minus 18 degrees. No life on Earth would be possible. Now, if we add an atmosphere, including natural greenhouse gasses, water vapor, methane, and carbon dioxide, approximately at a level of 280 parts per million, then we have a natural greenhouse effect. This rises the temperature from minus 18 degrees to plus 50. So it's a huge effect, an increase of 33 degrees, and this is what is called the natural greenhouse effect. And the main gas contributing to it is water vapor.
Now, if we continue and we add anthropogenic manmade greenhouse gasses, for example, we raised the carbon dioxide to 410 parts per million, which is more or less where we are right now, then we also add another layer of warming, as I said before, approximately 1.1 degrees, and this leads then to an average temperature of 16.1. And in this additional manmade greenhouse gas effect, indeed, carbon dioxide is the most important contributor.
You can see this confirmed on this slide. R oughly two thirds of the greenhouse effect is caused by carbon dioxide. Methane contributes more or less one sixth. There's an important difference between these two gasses, though, and this refers to their lifespan. Every molecule of carbon dioxide in the atmosphere is adding to global warming for the next 100 years and more. Methane, on the other hand, has a lifetime of about nine years. So cutting methane emissions is a very quick and good fix for short time period. But on the long run, we will have to reduce carbon dioxide emissions.
Let's have another look at the greenhouse effect. The first slide I showed you was, of course, an oversimplified as this is tool, but it has some more details on it. I would just like to repeat two elements. On the right side, you have the greenhouse this very important down welding radiation. And on the left side, you have the information that part of the incoming radiation is reflected by the Earth's surface. And of course, the brighter the surface is, the more radiation is reflected. This is important to understand some feedback loops.
The feedbacks are self reinforcing. For example, the most famous one is the ice- albedo feedback. The surface of the ice reflects 85 % of the solar energy, only 15 % is absorbed. The dark sea, however, only reflects 7 % of the energy and absorbs 93 %. Now, if global warming induces that the ice is melting and turning into dark sea, then more energy is absorbed, causing more global warming, causing more ice to melt, et cetera.
The same feedback happens with the melting of the permafrost that is a huge storage for methane and carbon dioxide. We can even see an increase over time of water vapor that also obviously has a feedback loop because warmer air can store more vapor.
Unfortunately, these effects are difficult to quantify. In fact, they are not included in many models. Let's quickly summarize the physics that we've seen so far. Temperature on Earth is a question of radiation balance. The natural greenhouse effect is at about 33 degrees and is a prerequisite for life on Earth. The anthropogenic manmade greenhouse effect consists in adding additional greenhouse gasses in particular, carbon dioxide and methane. Carbon dioxide in the atmosphere increased from more or less 280 part per million to 410, inducing an increase in global temperature of 1.1 degrees Celsius.
If we want to stop the global warming, this results in stopping greenhouse gas emissions. Let me turn to the second question. Since when do we know? Longer than you think. Many of you might be familiar with the Mathematician and Physicist, Jean-Baptiste Joseph Fourie Jean Bartiste Joseph Foyer. He was the first one to realize that the temperature on Earth is much higher than one would expect. The explanation he came up with was that the atmosphere acts as an insulator, storing heat that would otherwise escape.
Roughly 30 years later, John Tyndall proved that Fourier was actually right. He demonstrated that carbon dioxide absorbs and emits infrared radiation. Finally, at the end of the century, the Swedish Chemist, Svante Arrhenius,, was able to quantify the greenhouse effect, the amount of global warming due to the carbon dioxide emissions.
By the way, living in Sweden, he considered this a positive effect. He hoped that life would become more pleasant with a little bit warmer temperatures. I would like to jump to the '70s and show you 30 seconds from a very popular German TV show at that time. The host describes in detail how global warming works. It's in German, unfortunately, but I put subtitles in English so that you can read it. A gain, this is from 1978.
[foreign language 00:12:39].
The consequences will be dramatic. Isn't it incredible how precisely they predicted global warming in 1978? I find this amazing every time I see it. This TV host was not the only one who knew. Many companies knew, including.
[foreign language 00:13:45]
Here is, since then, Exxon. Exxon knew, and Exxon knew exactly. You might have heard about it because it just recently made the news. A group of scientists just published a science article assessing Exxon Global warming projections.
I would like to read two sentences from the abstract. The first one is, "Their projections were also consistent with and at least as skillful as those of independent academic and government models." In other words, they had excellent predictions and scientists. The final sentence says, "On each of these points, however, the company's public statements about climate science contradicted its own scientific data." This is a very polite way to express that they invested a huge amount of money to actually dismiss global warming.
As we do have the documents, I can show you this in a little bit more detail. This is the original letter from Exxon from 1982 called CO₂ Greenhouse Effects, and ending with the remark "Not to be distributed externally. For internal use only."
Exxon estimated the development of carbon dioxide in the atmosphere and global temperature until 2100. So let's zoom in. Here, we see the year 2022. And the corresponding most probable measurements that Exxon predicted were 420 carbon dioxide and increase of temperature of 1.1 degrees. This is spot on, right? A ll one can say is excellent work.
By the way, if you wonder why they were interested in this question, it was partially because they knew that global warming would lead to a rise of sea level so that they had to build their oil platforms higher. Now, with the First World Climate Conference in 1979, did climate policy have measurable success over the last 40 years? This is my final question to wrap up the historic part of this talk. Yes, no, or one can't say?
Very unfortunately, the answer is a very clear no. Below the graph, you see the famous temperature stripes showing the increase of temperature over the last 60 years. The graph itself shows the carbon dioxide in the atmosphere.
W e have the First World Climate Conference, the First IPCC Report, the First UN Climate Conference, the Kyoto- Protocol, the Copenhagen Accord, and finally, the Paris Agreement. During all these meetings, conference, and agreements, carbon dioxide in the atmosphere increased from 316- 420, the measure that we have right now. None of these conference, agreement or meetings had any measurable effect on our actual situation regarding climate change.
Finally, not to leave it to these a little bit depressing news, what can each and every one do about it? Let me first very quickly remind you that there is a practically linear relationship between temperature increase and global emissions. If we want to keep the 1.5 degrees goal from the Paris Agreement, we can very easily estimate that we have left approximately 500 gigatons of carbon dioxide. This was in 2020, three years ago.
Three years ago, we had 500 gigatons left for the 1.5 degree goal of the Paris Agreement. Now, if we relax this a little bit to two degrees, then we have 1,350 gigatons left. To demonstrate the current status of our emissions, I'm going to switch to JMP.
Let's start with having a look at the global emissions. If we look at it historically, since 1850, you can see the map on the left side of the main emitters, and I have the data here on the right side, the three top units that contributed historically to global emissions are the United States, responsible for one quarter, a little bit less the European Union, and 13 % from China. This adds up to roughly 60 % that these three top units are responsible for historically since 1850.
Now, if we look at the current status, so this is data from 2018, you can see here that the top three are still the same, but the order changed. China is now by far the country emitting most, followed by the United States, and third in place is the European Union. T hese three still add up to roughly 50 % of global emissions per year. The conclusion here is that without these players, we are not going to get anywhere.
Now, to make the comparison a little bit fairer, let's look at emissions per person. Here in the in this lower graph, you see the emissions per capita for different countries. The top ones are the Gulf states like Qatar and similar countries, followed by a second group of high emitters, Australia, Canada, and the United States. Then there is a third group that consists of China and the European countries in the middle. Then we have low- emitting countries typically found in Africa.
Now, please follow me on the following calculation. I said before that in 2020, we had 500 gigatons left. Now, it's easy to turn this into a per- person budget, which is 56 tons. I f we want to be carbon neutral by 2050, this leaves us 28 years, 56 tons. T he personal budget on average per year that is compatible with the 1.5 degree of Paris is two tons per person. This is this red line that you see down here.
Now, let's look at the United States, for example. For the last three years, the United States have emitted approximately 18.4 tons per person. In three years, they already used the 56 tons that they had left until 2050. On the top, you see the years left until the corresponding country has entirely used its budget. And you can see that the US, Canada, Australia, and Qatar, they are at zero or below. In other words, these countries already have used everything they had left to keep the Paris goal of 1.5 %. Every breath they take now, every car they drive, every plane they fly, is already on the depth side towards this climate goal. D on't worry, the Europeans are all going to follow in a future in a couple of years.
The conclusion of this is unfortunately that we have absolutely no chance to reach the 1.5 climate goal of the Paris Agreement. Every ton that we can save is good, but the 1.5 degree goal is gone. Unfortunately, there's agreement on this.
If we now look at the global emissions by sector to a little bit approach the question in what area we can personally contribute, then you can see that almost three quarter of the emissions come from burning fossil fuels, oil, gas, and coal. So if someone says the climate crisis is a global energy crisis, he or she is absolutely right. Almost three quarter of the emissions are due to burning fossil fuels. 20 % come from agriculture and then they are cemented waste.
Here in the middle, you see this in a little bit more detail, and I would just like to emphasize one, and this is livestock. Livestock is responsible for 8 % of global emissions. What that means is the following. If you put all the cows, pigs, and sheep, and everything in one country, looking at their emissions, they would be number three in the world. There's China, the US, and all the animals. The country consisting of all the animals would be the third biggest emitter on this planet.
This is one reason why agriculture is a huge contributor and is actually the field with the highest impact for your personal influence. Followed by buildings, meaning how you heat and the electricity, and the third question is how you move. So transportation, buildings, and agriculture are the three big contributors where you have personal influence on global emissions.
I would like now to turn the attention to these three fields. I will start with transportation because I think this is the best known. But it's always good to look at this personal budget. Let me remind you, your personal budget is two tons. One transatlantic flight Frankfurt- New York, consumes four tons. Twice your personal budget is spent on one transatlantic flight.
There are other ways to use your personal budget quickly. One luxury cruise seven days, 2.8 tons. Driving your fossil fueled car for one year, 2.3 tons. Everything already above your personal budget and you haven't eaten anything yet.
Generally, it will be known to you that taking a plane is the worst way of moving. You cut emissions more or less by half if you take the car and you cut emissions by one tenth if you take the train. Of course, public transportation is better than private one, and the best way to move is if you use your own muscle on a bicycle or just by walking.
Now, for buildings, the situation is quite clear. 60 % of the emissions come from direct or indirect use of fossil fuels by heating, cooking, and electricity. T he conclusion here is very easy. Turn to renewable sources for your power use in your house. Heating, cooling, electricity. Turn this into a greenhouse and you will significantly contribute to a reduction of your carbon footprint.
20 % almost of the emissions in the building's area come from building material. And it's very interesting that there's a lot of research going on to replace classic building material by carbon dioxide neutral or even negative one. And I included one example, this is a company from Switzerland that actually stores carbon dioxide into recycled concrete and tries to reduce the carbon footprint by this.
Finally, agriculture. I have here the data for four different diets and their carbon footprint. It's data from the US. It's not that easy to find the data for other countries, this is why I took the one from the US.
The average American diet, again, uses your full budget of two tons. If you leave out dairy or if you leave out meat, so you turn to vegetarian, this significantly reduces your footprint. But the really huge step is leaving out both and becoming a vegan. If you wonder why this is the case, it's because of the footprints of different types of food. You can see that all the vegan food here is in the lower section. This is split in methane and non- methane greenhouse gasses. And all the high emitters are in the upper ones. A ctually, I didn't arrange the scale right.
If you look at the top, beef from beef herds, it's not 40, neither 50 nor 60, nor 70. It's actually 100 kilograms per kilogram of the corresponding food. I f you only want to do one thing, in your diet, leave out beef. Personally, I find one of the most impressive statistics, this one, 29 % of our Earth's surface is land, 71 % is habitable. Half of it we use for agriculture. Of this part, 77 % is directly or indirectly used for livestock. This is one third of the habitable land, but we only produce 18 % of calories from meat and dairy.
This is why the lead author of the corresponding article, Joseph Poore says, "A vegan diet is probably the single biggest way to reduce your impact on planet Earth, not just greenhouse gasses, but global acidification, eutrophication, land use, and water use." He himself turned vegan after conducting the study.
Let me just wrap up a little. H ere are the four actions I introduced in the beginning, and I hope that by now it will be no surprise anymore to anyone that going vegan is the most efficient thing you can do. No plastic bags is good for the environment, but it doesn't really have an important impact on the carbon footprint.
Here are the answers from the survey I showed you. And as you can see, no plastic bags was the answer with the highest rank, highly overestimated, just like only eating regional and seasonal food. And on the other hand, reducing meat was highly underrated.
I would like to wrap up with a quote from Al Gore, where maybe because it's not 100 % clear that he said it, "Vote, voice and choice." What can you do personally? You can vote in every election, make climate policy a priority, and let officials know what you want. Make your voice heard. Support organisations, talk about it in your company, et cetera.
Finally, your personal choices matter. Ideally, eat a plant- based diet, reduce use of fossil fuels for mobility, in particular flying, and make your home green by using renewable energy for electricity and heating.
My contribution to making our voices heard was to give this talk today. I would like to thank you very much for taking the time to listen to my message.
