"Climate change is a fact, not a matter of belief."

He is a physicist, astronomer, philosopher of nature, and author. And he is one of the most well-known scientists in Germany. Since 2008, Prof. Dr. Harald Lesch (64) has been quietly, yet competently, passionately, and most importantly, understandably addressing scientific topics of all kinds on ZDF. His home broadcaster, ZDF, calls Lesch an "exceptional phenomenon." On Wednesday, November 27, "Germany's most famous explainer of the world" (Bayerischer Rundfunk) will come to the Academic Year Celebration at the University of Bayreuth in Bayreuth. Lesch will give a lecture in the Audimax on "How do we talk about nature?", in which he will also delve deeply into the topic of science communication. What drives Harald Lesch, what annoys him, and the role he assigns to science are things he explains in the interview we conducted with him in his office at Ludwig-Maximilians-University in Munich.

UBTaktuell: You have often been to Bayreuth, usually to exchange knowledge with colleagues as a physicist. Now, you are coming in a new role, so to speak, to deliver the keynote speech at the academic year celebration. You will talk about nature, and it will focus particularly on science communication. Why is this topic so important to you?

Harald Lesch: The last time I was in Bayreuth, I gave a lecture on climate change at the invitation of 'Students for Future'. Frankly, I have been talking about almost nothing but climate research and the energy transition for over a decade. Why? Because I consider the topic incredibly relevant. Firstly, because it describes the thermodynamic state of our planet. But what also irritates me is the way this topic is so wrongly discussed in society. It is utterly incomprehensible to me that there are still people who deny climate change. Those who do might as well claim that the sun rises in the west, not the east; or that the periodic table is incorrect, or any other such nonsense. No, climate change is a scientifically proven fact, not a matter of belief. Several years ago, when the Americans first elected Donald Trump, the term 'alternative facts' was coined. And this seems to me to be a weapon that destroys democracy. I am pushing back against this with everything at my disposal – as a scientist and as a journalist...

...which I assume, may well cause some controversy.

I don't care if it causes controversy because I feel obligated to the truth. They surely made me a professor and have supported me for almost 30 years not to shy away now. That wouldn't be my style. And I also wish that more of my colleagues would take clear positions and, above all, ensure that misunderstandings are cleared up and facts are clarified. This will also be a topic in the lecture I will give in Bayreuth—that I unfortunately experience a silent research landscape, at research institutes as well as at universities. These people are supported by society. Those who remain silent and do not speak up when Germany or the continent of Europe walks into a trap with open eyes are not fulfilling their societal responsibility. Science must not accept that the entire network—which today is the main source of media information—is flooded with nonsense (sorry for the word!). That cannot and must not happen. We have to fight against this.

Do you believe that those who doubt climate change feel validated by the announcements and statements of Donald Trump?

Well, of course! I'm also really concerned about the next federal election. It will again be about changing energy policies, which is actually all nonsense. We can see how the installation numbers for photovoltaics are doing, as well as for wind turbines. We see that we have 60% of our electricity from renewable sources. Renewable energy is skyrocketing everywhere in the world. Only here in Germany are we supposed to suddenly make a U-turn? Even in the USA, coal will not be burned in the future. Why would one do that? The kWh from coal power is much too expensive, the kWh from nuclear power is much too expensive. So let's finally stop clinging to old junk.

The COVID-19 pandemic has changed the world, including significantly impacting science communication. You yourself spoke in March 2020 of a "revolution in science communication." Four years later: What remains of this revolution?

Yes, it would have been a great opportunity to revolutionize it. Unfortunately, by 2021 it became clear that we were not very successful in making the population understand how science works. People were completely uncertain. Yet, questions, doubts, and debates are part of scientific research: when you don't yet know how things are connected, you have to probe, search, and research. Sadly, people did not engage with this search process; they always wanted the absolute truth right away. Thus, for the first time, society experienced live how science operates, inquires, and searches, without immediately knowing everything. Nevertheless, I believe that the population still has a great trust in science. Otherwise, people wouldn't continue to visit the ophthalmologist, undergo laser treatments, ride in high-speed trains, or fly in airplanes. All these technologies are science-driven, not some kind of sorcery by a shaman. However, it must not be forgotten that there are still people who, when facing a tumor disease, believe they can treat it with homeopathic globules. That's of course all nonsense. Therefore, scientists must ensure that people do not fall prey to charlatans. That's why it is important for science to be present, to bring joy, and for that joy to be showcased.

Science can indeed trigger joy?

Absolutely!  It's not just about the content but also about the human touch. When a middle school class tells me, "We believe you, you are an honorable man," that's the highest honor I could receive. It almost brought me to tears. Ultimately, it's about the values we live by, and these are major topics for discussion. I wish that we could discuss these issues at events like the one in Bayreuth. I find it incredibly important, in a country so reliant on science and research, that science and research reach the public, that universities open their windows, as Pope John XXIII once said, to let fresh air into academia and allow the public to somehow drive research. People have a right to have science address issues that concern them.

Do you believe that science, broadly speaking, has also learned the right lessons from the COVID era and from the processes and criticisms that arose, given that many scientists experienced severe backlash?

Indeed, the situation you describe reflects significant challenges within the science community during times of intense public scrutiny. The lack of protection for those inexperienced with public communication was a considerable oversight. Moving forward, it's crucial for the scientific community to develop stronger support systems for its members, ensuring that they are adequately prepared and shielded when engaging with the public, especially during crises. By standing together and addressing issues comprehensively, the community can better navigate the complexities of public interaction and criticism, ultimately enhancing the resilience and effectiveness of science communication.

At the University of Bayreuth, the interdisciplinary approach has been long-established and is highly successful, especially in challenging research areas like Artificial Intelligence. 

Yes, the fear factor also plays a certain role with AI: you simply have no idea what is going on in these boxes. Until now, we always knew exactly what the machines were doing. And now, all of a sudden, we have to deal with the fact that the inside of these machines is changing because the software is changing. And there are, how should I put it, very specific difficulties that scientists don't even think about at first. We once asked a representative of Munich Re, a reinsurance company, what they actually insure in an AI process. The Monday morning version or the Thursday afternoon version? So if there are constant transformations like this and you don't know what dangers are involved, then these are incalculable risks. Especially if we release these algorithms into the real world, where there are many more players who have completely different hopes, visions, dreams and goals than those who work in university institutes, perhaps driven by knowledge.

The topic of science communication has also received a certain boost from politics. There was a joint motion by the SPD, FDP and the Greens, who advocated the sustainable expansion and establishment of science communication. You yourself advocated this at a public hearing. Do you think politicians have understood that science communication is a huge issue and also socially relevant?

At the expert meeting and in the committee, I definitely had the impression that there is a great deal of interest in the topic - also from the university side, by the way. That wasn't the case for a long time. In this respect, science communication has managed to move to the center of science. And politicians are simply realizing that a well-informed population is better off than a dubiously informed population.

Take the USA, for example. A man has been re-elected who demonstrably lies, says stupid things and has a criminal record to boot. So, high times for science communicators?

Of course! I said in a lecture last week that if the superpower under whose military umbrella we live suddenly develops socially in such a way that truth no longer has any meaning for it, then it will become dangerous very, very quickly. And if, for irrational reasons, the USA no longer guarantees us a protective shield, then we should arm ourselves very quickly, because we have to fear that there are attackers in Europe who are clearly threatening us. Of course, science is also called upon in this process. I am very excited and very much hope that many more of my colleagues will tackle this issue and also recognize the danger of not speaking out clearly and comprehensibly.

Speaking of comprehensibility, you once quoted the philosopher Hannah Arendt in an interview, who wrote in her 1958 book “Vita activa”: “If the public does not understand science, then people will turn away from it.” So have we reached this point?

So I can only point out that this philosopher should be placed at the center of a discourse because she discussed the question of power and, in particular, the role of science within society. She reported very early on how difficult it is for the natural sciences, whose language is mathematical, to translate this into the language used in the political sphere, namely our mother tongue. You have to take the time necessary to carry out such an act of communication with society in a way that is really satisfactory for both sides. But since time is money and money plays such an important role at universities, the very time that is needed to do this is often not available to colleagues.

You yourself don't just talk about science communication, you actually do it. How difficult is it in practice to communicate clearly when dealing with highly complex issues?

You have to try it out, that's the interesting thing. There are no patent remedies. You have to try it out and find out what works best. I realized relatively early on that it's very important to limit yourself to one issue. In other words, not to think that you have to present everything. I'm a big fan of the Pareto principle: 20% effort, 80% effect. In other words, I'm not a perfectionist. Of course, you can say more and more and more about every topic. I prefer to say: We'll clarify the other things next time. It's much more important to think about what motivates the other person to listen to you. Why should they want to know what you have to say? That is the most important motive for me. If I can't find the motive, I leave it alone. And then I try things out.

And how long do you work on a program like this?

Very differently. The big TerraX programs are very elaborate productions that are often produced years before they are broadcast. We also have the programs that appear monthly. It takes two or three days before everything is in the can. Of course, the editorial team has prepared the topic well with me beforehand. I couldn't put in any more effort, because I'm a full-time university professor.

Do you have the impression that researchers and students are prepared to expand their efforts in the field of science communication and invest the time it takes to do so? And are the universities also doing enough to give the topic the necessary momentum?

Let me come back to the Pareto principle: you can certainly ask yourself: how much effort do we have to put in to achieve 80% impact? I have the impression that many university leaders have now understood this. Newly appointed presidents are immediately involved and have someone in their rectorate or executive board who deals with science communication. There are an incredible number of people at the university who are dealing with this topic in a very professional manner. Especially among the students. Because they want to make their own YouTube channel or something. That's actually the ideal medium. And incidentally, something is being created that I think has been pushed back a bit by the Bologna Process - namely the ability of academia to speak. Suddenly there are young people who can explain things really well. And I think that's wonderful. You should go out among people much more often. And talk about science with normal people in pubs or schools, for example. I can and want to shout out to everyone, including through this interview: People, this is incredible fun!

Do you also look around the net to see what's going on? On TikTok, for example?

No, no, no. I'm completely out of that. I have an editorial team that takes care of it, which then informs me - filtered accordingly - about what you absolutely have to do and what kind of video is hot right now. But I don't take care of it myself. I hold back completely, partly out of self-protection. I do what I can do and I also know that I should perhaps do a lot more, but that's all I can do. My day has 24 hours, my week has seven days and I'm already pretty busy with that and I can't do any more at the moment.

A more fundamental question: what responsibility do scientists actually have in our society?

First of all, it is not easy to talk about this with scientists because the topic of responsibility does not feature at all in our training courses. Surprisingly, we don't have an external perspective from which we look at our sciences. Philosophy sometimes does this, but the contacts between empirical research and philosophy are still rather underexposed. Much more could be done there. The other thing, from my position, I would always say that the simple fact that society finances science puts it under an obligation to society. That is the clear fact, so to speak. There is someone here who is paid and who has to provide a certain service. In addition, a responsibility naturally arises in that the wealth of knowledge produced by the empirical, i.e. the natural and technical sciences, naturally gives rise to a responsibility to communicate when dangers are lurking. And when there is a need for information. For example, I would love to give a lecture in the Bundestag on climate change. Just to give the MPs comprehensive information. I have the impression that the scientific process, the work of scientists, is still far from being understood in society. That doubts are also part of the principle of questioning things and discussing them controversially.

A more personal question: is there actually a scientific concept that has changed your view of the world?

Yes, a book by Carl Friedrich von Weizsäcker, “History of Nature” from 1948, which brought together my absolute weakness for history with my enthusiasm for the natural sciences. And it's my favorite lecture that I give. The history of nature from the Big Bang to the present day. It covers all the natural sciences, but also anthropology, the origins of humanity, the social sciences and philosophy. This Big History story has practically expanded my scientific world view exponentially.

If you hadn't become a physicist, what would you have become?

An electrician, like my son and my father.

Is there a life motto or principle that you live by and that you have rarely shared?

Fear not! That's how you can summarize the New Testament and it's my motto in life.

On the subject of music, you've already revealed your tastes. You are a fan of jazz music and David Brubeck. When asked by BR which musicians you would like to have met, you answered like this: Franz Liszt or also Franz Schubert. Schubert perhaps even more. Now you are coming to the city of Richard Wagner. Do you have any connections to Richard Wagner?

None at all, no! I know the overtures from Wagner's operas, but unfortunately I can't do anything with the Ring or anything else. Sorry, I'm out of it.

Wouldn't it be worth a try in Bayreuth?

Lesch: Well, I've heard that the chairs are very hard... No, Dave Brubeck is still my hero. But people like Liszt or Schubert and the great Mozart also fascinate me, of course. And as I play the piano passionately myself, but very badly, it's certainly these people who make an incredible impression on me.

Now you are coming to the University of Bayreuth's ceremony on November 27. What do you wish this university, which is celebrating its 50th birthday next year? What advice would you like to give it?

Well, I know of a few interesting developments within the University of Bayreuth; we have someone in our family who studied philosophy and economics in Bayreuth. And I think that's a great combination. That should be done much, much more often. In Bayreuth, they obviously have the courage to tackle such new combinations of subjects instead of always working in the same trenches. And the university should definitely retain this courage. Perhaps it should become even bolder and try out even more new things so that the university becomes a lively, diverse and intellectual landscape where the joy of science and exchange can be felt by everyone.