While our climate is rapidly changing, one of the most important systems needed to address this crisis remains largely unobserved: our ocean. Absorbing around 90 percent of the excess heat from greenhouse gas emissions, the ocean and its ecosystems play a central role in regulating temperatures on land and, in turn, directly influence how our societies function. To use our oceans wisely and protect the life they support, we first need to understand them and their biodiversity. This requires increased funding and stronger efforts to measure how this vast ecosystem operates and what changes in its functioning mean for our future.
Sjoerd Groeskamp is strongly committed to this mission. As a senior scientist at NIOZ and a theatre and podcast maker, he works to make knowledge about the ocean more widely accessible. He believes that addressing climate challenges is not just about advancing science, but about connecting science with the arts to reach broader audiences and enable systemic change, bridging the gap between scientists, policymakers, and the wider public.
In this interview, Sjoerd explains the role of our oceans, why their biodiversity and climate functions have long been undervalued, where communication gaps in science lie, and what we can actively do to better understand and respond to the changes shaping our planet.
Could you briefly introduce yourself and your work?
“I am a senior scientist at the Royal Netherlands Institute for Sea Research (NIOZ). My main field of study is physical oceanography. You could think of me as a meteorologist, but for the ocean. Specifically, I study the processes of mixing and water mass transformation in the ocean.”
“Mixing in the ocean is like stirring milk into your coffee with a spoon. In my work, I study the ‘spoons’ of the ocean.”
“In the ocean, warm and cold water mix, as do salt and fresh water. I investigate the forces that drive this mixing of water masses. This is crucial because mixing impacts how much heat and carbon is transported into the deep ocean where they can be stored for long periods. This process directly affects the climate change we experience on land. In addition to this, I dedicate a lot of time to communicating the role of the ocean in the climate system through various platforms.”
What motivated you to work in this field?
“It just happened. In high school, I gravitated toward physics because I preferred it over languages. I wanted to continue studying physics at university. I chose Utrecht University, where I could study physics and astrophysics, with an introduction to meteorology. However, after taking an introductory course in oceanography, I found that much more interesting.
I remember one class where a lecturer derived equations of motion for the ocean. It resulted in one small equation that explained global wind patterns and upper ocean circulation. It turned out that 80 percent of what we measure in the real world is captured by that one elegant equation. I thought that was really fascinating and wanted to understand how it works. I began pursuing more subjects in this field and eventually completed a PhD in it. It was never a predefined plan. I simply followed the things I found most interesting.”
You mentioned your work in communication. Was this a passion that grew over time, or something you fell into?
“Both. It combines two things I love. As a teenager, I had a job where I worked as both a butler and a performer, singing for the people I served. I did that for six years. I really enjoyed it and became comfortable being on stage.
Later, I published a paper on sea level rise, a topic that concerned me, especially coming from the Netherlands. In the paper, I proposed the Northern European Enclosure Dam, a gigantic dam that would enclose the North Sea from the Atlantic Ocean. My goal was to illustrate a stark reality: if we do not stop climate change, we may be forced to build extreme and destructive structures to prevent our cities from flooding. The story received a lot of attention. As a result, I appeared on radio and television for years discussing the ocean’s role in climate change, which I greatly enjoyed.
Eventually, I met a Dutch comedian and together we created a theatre show. We toured the Netherlands for a year and a half, performing about 50 times. After each show, we interviewed a key figure in the climate field and turned those conversations into a podcast. It created a kind of flywheel effect. Once you start, people know where to find you and you meet many others doing important work in the climate space.”
When people think about climate change, they usually picture the atmosphere. What role does the ocean play in regulating climate change, and what impact does this have on the ocean itself and its ecosystems?
“When greenhouse gases warm the atmosphere, about 90 percent of that excess heat is absorbed by the ocean. Roughly 9 percent goes into warming land and melting ice, and only 1 percent remains in the atmosphere, which is the warming we actually feel. This means that even small changes in that balance can have a major impact on future projections.
The ocean also absorbs about 25 percent of the carbon we emit. Without this, the greenhouse effect would be much stronger. However, this carbon also makes the ocean more acidic. Combined with rising temperatures, this creates conditions that many marine ecosystems cannot tolerate. Most ecosystems, such as coral reefs, are fixed in place. If temperatures exceed their limits, they die. Fish can migrate, but this introduces invasive species that disrupt existing ecosystems, leading to biodiversity loss. As a result, ecosystems become more uniform globally, with fewer species and less variation between regions.
Furthermore, because the ocean regulates climate on land, it also affects biodiversity there. In the Netherlands, for example, we have seen that 80 percent of insect biomass has disappeared over the past 30 years.”
“We do not yet fully understand the balance between the ocean and the atmosphere, especially at the level of precision that matters most for climate predictions. That is why this research is so important.”
As you mentioned, large parts of the ocean remain poorly observed. Why is it so difficult–and yet so critical– to measure our oceans?
“The reality is that we have mapped the surface of Mars in more detail than the bottom of our own ocean.”
“That is striking if you think about it, because the ocean provides us with food and regulates our climate both on daily and centennial scales. Therefore, it has a massive impact on our society. Nevertheless, the reality is that we spend very little money and time observing the ocean compared to astrophysics or meteorology. We use about 4,000 drifting floats to measure the ocean, which sounds like a lot, but they cannot even cover half of the sea. The measurements are often very limited and localized.
For example, we monitor the Atlantic Meridional Overturning Circulation (AMOC), which transports heat to Europe. If it slows, temperatures in parts of Europe could drop significantly, up to 20 degrees less in some places. Yet, the funding for this monitoring is always up for grabs and therefore very vulnerable. We spend about 20 million a year on this, which is a very small amount compared to other things that we study, like the 1 billion annual budget for a particle accelerator or the 10 billion cost of the James Webb Telescope. We are looking away from Earth rather than into the ocean that influences our daily lives.
Our ocean has been an undervalued part of our economy and our climate system. That is something we have to change. Together with others, I am determined to achieve this. We are slowly starting up both the legal side of it as well as our understanding about it. But there continues to be only a small amount of money going to ocean observations.”
You have worked with large groups of scientists to synthesize knowledge for policymakers. What are the main challenges when translating complex ocean science, including biodiversity loss, into policy advice?
“Scientists are used to communicating with precision, using ‘ifs’, ‘buts’, and probabilities. To a politician, a probability can sound like a reason not to act. Reports like the IPCC help bridge this gap. But it takes a lot of effort and globally coordinated projects. Besides that, politics is often driven by personal connections that are difficult for scientists to create. We need more ‘middle-men’--people who can put these two groups in the same room. Or we need to teach scientists to communicate with politicians. They need each other, because scientists have the knowledge and the politicians have the power.
While the IPCC helped lead to the Paris Agreement, policymakers are also balancing climate against other economic or social issues. Interestingly, we do see that some of these other issues now overlap with climate change. For example, even some military leaders are now advocating for climate action because they see it as a direct threat to the issue of global security.”
Through your podcast Overvloed and your theatre show you have also explored creative ways of communicating about climate change and biodiversity loss. Why do you think storytelling and creative formats are important for science communication?
“The IPCC summarised the scientific evidence and told policymakers that the world is in crisis and action is needed. In response, policymakers have taken steps, but these are not sufficient. We were heading toward six degrees of warming. Thanks to international agreements, we are now on track for around three degrees. However, this still represents a highly dangerous future. Ideally, we want to remain between one and two degrees of warming to reduce the risk of triggering extreme and potentially irreversible changes.
I do not believe this can be achieved through policymakers alone. It requires convincing the public that climate change is a fundamental issue.
Changing people’s perspectives is difficult. To reach a broad audience, we cannot rely on facts alone. We need stories that help people feel the reality of the situation. This is where art and communication become essential. Art can achieve what data alone cannot. That is why I chose to work in theatre and why I believe it is so important.”
What would you advise people who care about biodiversity but do not work directly in science or conservation? What can they realistically do to make a difference?
“Take action. We need many people to recognise the problem and contribute. However, I do not believe that individual actions alone, such as cycling instead of driving, will solve climate change. We need to channel that motivation into systemic change. It is impossible to live a carbon free life within a system that depends on carbon. Whether through your expertise, your time, or your role within an organisation, consider how you can contribute to systemic change. That is where real impact lies.
We already understand the fundamentals: climate change is a societal issue, humans are responsible, and action is required. How we will manage this in the long term through systemic change still requires significant research. This means we must evolve both our collective mindset and our infrastructure.”
“Every molecule that we do not emit, is one worth fighting for.”
Acknowledgements
We would like to sincerely thank Sjoerd Groeskamp for sharing his time, valuable insights and vision. His work at NIOZ demonstrates how both an understanding of our oceans and the right communication of that knowledge, are essential to tackling the system change needed to protect our climate.