Text: Marjolein de Jong | Photo: David Meulenbeld | 5 June 2025
The climate model Rotmans developed then is still used today. What kept him going? A deep-seated feeling: this is not right. He worked 100 hours a week, against the grain, often on his own. But recently he started babysitting his granddaughter on Mondays. 'You can't spend 40 years ranting like a hurricane. Balance is desperately needed: for ourselves and nature.'
You have just returned from Curaçao. What were you doing there?
'I was there during Green Week and gave five lectures to diverse groups, companies, banks, the university and citizens. What you notice immediately when you are there: you go back in time 15 years. The island once leaned on an oil refinery, but that has shut down. Tourism is now flooding the island, while half the population lives below the poverty line.'
'Sun and wind should be the island's strength, but they are barely exploited as energy sources. I say then: make sustainability the new engine. Give poor people in particular solar panels on their roofs, so they can generate their own energy and even earn from what they feed back. The island is at a tipping point and more and more people are realising that things have to change.'
'Transitions always take a long time. They start small, grow slowly and then suddenly there is an acceleration.'
And when you speak there - or at other conferences - what do people want to hear from you?
'Hope. Many people think the energy transition has stalled because of Putin or the high costs, but that picture is not true. Worldwide, on the contrary, more investments are being made in renewable energy than ever before. Sun and wind are now so cheap that they can already compete with fossil fuels in 30 countries.'
'Of course I also worry sometimes, about Trump for example, and all the idiotic things he shouts and does. But 90 per cent of what he says is eventually reversed anyway. Whether by the courts, his own party or the financial sector. We allow ourselves to be held hostage too much by figures like that.'
But are you really hopeful? Or mostly combative?
'Both. Transitions always take a long time. They start small, grow slowly and then suddenly there is an acceleration. Usually this happens because of an external accelerator: a war or an earthquake. Research reports don't convince enough, but chaos can. We are now in the middle of that chaos phase and so this is a very exciting time.'
'That scepticism against everything I start has actually never gone away.'
You started at a time when the climate problem didn't exist. What was that like?
'Lonely. I studied mathematics, and as part of my thesis built a model in which I wanted to capture everything. Where do emissions come from? How does CO2 spread? And what are the consequences for nature and the economy? People declared me crazy, or worked against me. And yet: that same model, IMAGE, is still being developed today and has been used in all climate negotiations.'
'That scepticism against everything I start has actually never gone away. Each time I was put away, reviled. When I first wrote about transition research, De Telegraaf headlined on the front page: "Professor Rotmans victim of his own hype." We wouldn't hear much more of the word transition.'
You later became an activist scientist.
'Yes. That tipping point came after a violent cycling accident in the Pyrenees. That's when something in me started to tilt. After that accident, I had to rehabilitate for a year and suddenly found myself at home. That kind of crisis separated the sense of noise. I asked myself: did I actually become who I wanted to be? As a child, I had two dreams: to become a professor and to make the world a more beautiful place. The former had succeeded, but I felt I had too little impact outside science.'
'I decided to be more activist and then started the Urgenda Foundation, among others, but I was not thanked. They said that as a scientist you have to remain objective. And I thought: but the problem is too big not to speak out.'
'I hope the earth will also regain the balance with us.'
What has that years of resistance done to you?
'My back is full of scars. You don't see them, but I feel them. Especially when your wife and children are threatened. Meanwhile, the university received letters asking for my dismissal and in major newspapers I read the most terrible things about myself. Naturally, I started having doubts. Still, I continued, because I felt it was right. But it eats away at you.'
'You can't be angry for 40 years either. So fortunately, I always maintained a certain lightness. I celebrated life, otherwise you don't last. With friends, it wasn't always about the climate and I could also just stand on the bar in the pub. Moments like that are my outlet. A way to shake off the madness.'
Who supported you?
'In the Netherlands hardly anyone. I found a few like-minded people abroad, especially in America, and that saved me. And I had an indestructible belief in myself and what I was doing. Although I pushed it. I was working 100 hours a week and was always 'on'. But then you get out of balance, I know now.'
'These days I live more consciously, more quietly and babysit my granddaughter every Monday. That helps me ground myself. And I hope the earth also regains balance with us. Because if the earth is sick, eventually we will be too.'
'I had to cry. Not from helplessness, but from the realisation: this must not be lost.'
Meanwhile, your message is also: knowledge is not enough. How did you realise this?
'At the North Pole. I was standing on a melting glacier. It was nine degrees, far too warm for that time of year. There, among those ice formations the size of apartment buildings, it suddenly became quiet. There was such a bright light. It was as if something went through me. I had to cry. Not from helplessness, but from the realisation: this must not be lost.'
'I thought: I keep sitting with all my models and scenarios, but I feel this so deeply. Then I knew: I have to touch people not only in their heads, but also in their hearts. Knowledge alone is not enough: it only leads to more knowledge and sometimes to paralysis. But feeling sets people in motion. Because if you manage to touch people, it is irreversible. I have experienced that myself. Since that experience, I feel much more connected to nature, and to the universe. When we feel that we are part of something bigger, we also start taking better care of it.'
Is the biggest challenge to change within ourselves?
'That's right. Change is something we as humans fear deep down. Evolutionarily speaking, change once meant danger. You either had to flee, or you fought. That mechanism is still in us. When something fundamental changes in our world, we automatically shoot into resistance. But if we really want to change, we have to let go of that reflex. That is difficult, but also liberating.'
'The real challenge is yet to come and that is the toughest. And yet I believe it will work out.'
Where do you think we are concretely when we talk about the climate problem?
'I am convinced that we are going to solve it, in the sense that we can limit the damage and keep it liveable in large parts of the world. But it's not going to happen by itself. And billions of people are going to be affected locally and regionally.'
'Meanwhile, I see something much more important happening: we are making sustainability without thinking about the next step. Because what happens to all those solar panels, wind turbines and batteries, which are only usable for a few years and then end up in a huge landfill? The real challenge lies in embracing an economy that has to be circular, where we design with reuse of raw materials from the start.'
'I sometimes compare where we are to a marathon. We have now run 10 kilometres out of 42. The real challenge is yet to come and it is the toughest. And yet I believe it will work out. Not because I can prove it scientifically, but because I feel it. We have escaped something in the nick of time before in history. It will happen again, I am convinced of that deep down.'
