Senior professor Teun Terpstra was recently interviewed for the National professors’ Platform for Climate Change and System Transition (LLKS), which aims to accelerate system transitions for a resilient society. Teun is a professor in Resilient Deltas, a civil engineer and behavioral scientist, specializing in water safety and the future of the Southwestern Delta.
When Teun talks about his work, there is a sense of urgency, but also a striking calm. For him, climate adaptation is not an abstract theme, but a daily driving force: not only developing effective measures, but also ensuring that people are willing to embrace them. “Without public support, nothing happens.”
The Netherlands is a country of rivers and coastlines, partly below sea level. Due to climate change, sea levels are rising, soils are becoming salinized, both winter peak discharges and summer droughts are increasing, and the land surface is subsiding. “In the coming decades, we will have to make choices that are decisive for what the Netherlands will look like,” says Teun. “We live in a delta that is becoming increasingly vulnerable. That calls not only for technical solutions, but also for a shift in our way of thinking.”
A dynamic system
That shift begins with the realization that our delta was once a dynamic system. Rivers and tides caused erosion and sedimentation, as well as flooding and land formation. Through human interventions such as dikes, dams, pumping stations, and canalization, we have tamed natural behavior and largely halted that dynamism. This has brought us a high level of safety, but at the expense of water quality, ecology, and especially the ability of estuaries and the Wadden Sea coast to grow along with sea-level rise. “We don’t need to abandon the idea of controllability or the notion that humans can manage nature. After all, without the dikes and dunes of the past, a large part of our country would be uninhabitable—and the same applies to the future. But it would also be good to realize that natural processes can help us allow the land to grow along with sea-level rise. Land-level rise, therefore, for our safety and for nature restoration.”
Is that why your research group is called Resilient Deltas? “Yes,” says Teun. Resilience is about finding an adaptive balance between three values that often conflict: safety, ecology, and economy.
“If you close everything off, you can technically build a safe delta. But you destroy ecology and hinder economic sectors such as the ports of Antwerp and Rotterdam. If you opt for a fully natural system, you would have to remove the dikes and could no longer live here. It’s about finding a balance in which the system is designed so that all three values are well served and long-term adaptation remains possible.”
Extra protection
The most striking example from Teun’s research group is the study of exchange polders: areas along the Western Scheldt where tidal influence is allowed behind the sea dikes, so that sand and silt accumulate and the land grows along with sea-level rise. “In this way, we restore ecology and create extra protection against sea-level rise.”
The project has been running since 2022 and has sparked debate. “In Zeeland, exchange polders are a very sensitive issue,” Teun explains. “Several opposition parties in the Provincial Council submitted motions against exchange polders and against the provincial executive who supports them. Newspapers were filled with it for weeks.” At the same time, more and more parties are embracing the idea.
“As researchers, we are right in the middle of that field of forces: providing knowledge and playing an active role in the discussion. Sometimes that also means correcting misinformation and showing what is correct. That’s not always pleasant, but it is necessary—and it’s impact in real time.”
Especially with such far-reaching choices, the human side plays a crucial role. Teun recounts how a resident emailed him saying that her living environment had been discussed for months without anyone involving her. “That touched me. Because although I believe the idea of an exchange polder should be further developed, this is also about the living environment of people like you and me. I have not met this resident, but she is the little voice in my head that sometimes says to me, ‘… and what do you think I think about this?’”
He sketches a future in which a healthy, resilient delta goes far beyond large-scale waterworks: it starts with removing pavement tiles, infiltrating rainwater, restoring natural processes, transitioning agriculture, and ensuring freshwater availability. “A resilient Netherlands does not see nature as a luxury, but as a prerequisite for our prosperity.” But he warns: “If we wait too long, only fast, technical ‘quick-fix’ solutions will remain. Then we will no longer have the time to let natural processes do their work.”
A transition is chaotic
The Netherlands can only make this transition with politics that dares to make long-term choices now, such as experimenting with exchange polders. “A transition is chaotic: there is a lot at stake, uncertainty dominates, and that creates friction. It is crucial that politics makes those losses visible and dares to offer a vision of the future. Avoiding solution pathways means being unable to make well-founded choices later. If we delay, we do neither ourselves nor future generations a service. Because one thing is certain: we can wait, but sea-level rise will not.”
Still, Teun ends on a hopeful note. He sees a powerful undercurrent of researchers, policymakers, NGOs, engineers, students, and farmers. “Despite the headwinds, I see so much energy, motivation, and optimism. Knowledge and awareness are growing rapidly. That process can no longer be stopped. Every transition starts off sluggishly, but at some point it tips. I think we are now entering that phase.”
His message: working with a future-oriented mindset requires personal motivation and curiosity. “Being inspired really helps,” he says. “Despite the sometimes gloomy topics, I see people every day who conduct research with enthusiasm and dedication. They know their work is necessary and that gives them the strength to keep going.”
This interview is part of the LLKS series ‘Accelerating Together’.
