In the late 1960s, oceanographer Carl Wunsch was teaching at the Massachusetts Institute of Technology (MIT)… but calculations being made from a classroom were proving insufficient. To understand the immense mechanism that regulates the planet’s climate, he went to sea, in order to measure and observe a system so vast that no research had yet been able to encompass it.
That decision would define his career. The New Yorker, now 85, became one of the great architects of contemporary physical oceanography. He developed methods to observe and quantify the state of the oceans, with unprecedented precision.
His work has been hailed as revolutionary. The observation systems he helped develop have made it possible to more accurately measure how much heat the oceans absorb, track rising sea levels, understand ice loss at the poles, as well as anticipate some of the most serious effects of climate change. Hence, it’s no wonder that the Bilbao-based BBVA Foundation recognized his legacy earlier this year, when he received the Frontiers of Knowledge Award, in the Climate Change and Environmental Sciences category.
Question. The ocean plays a fundamental role in the climate system. But for years, much of what was happening beneath its surface remained out of our sight. How did you manage to study it?
Answer. This wasn’t the work of a single person. Hundreds, probably thousands, of scientists from all over the world participated. What happened in the last 30 years was a complete transformation of oceanography. For more than a century, we depended almost exclusively on research vessels. They were essential, but they were also slow [and] very expensive. And they could only offer a very partial picture of the ocean.
We realized that we needed to observe the ocean as a whole system. At the same time, new technologies emerged, such as satellites capable of covering virtually the entire ocean surface, [as well as] autonomous vehicles that could spend months, or even years, taking measurements. [We also improved] cooperation between countries, sharing ships, instruments, and data.
We still need ships, because there are measurements that can only be taken from them… but now, they’re part of a global observation system.
Q. Which scientific advance was the most decisive?
A. The fundamental change was discovering that the ocean is far more dynamic than we imagined. For decades, we thought of it as a vast system that evolved very slowly: warm water on top, cold water below, with few relevant changes. But now, we know that’s not the case. The ocean changes on a large scale [every few hundred miles you traverse it] and at all depths, from the surface to the bottom. There’s enormous turbulence… a complexity that was completely invisible [when using] traditional methods. Before [the latest technology], no one could just leave a ship motionless for years, observing the same place.
Q. How did the experience of facing both the harshness and the beauty of the ocean influence you?
A. When I was a university student, I had a professor of physical oceanography who convinced me to go to sea. Honestly, at first, I wasn’t very interested. We set sail from Woods Hole (a port in Massachusetts) and we got caught in a terrible storm. I got extremely seasick and thought, “This is awful. I’ll never do this again.” But then, the sun came out, the sea calmed… and I understood the extraordinary beauty of working out there. It was a completely different way of doing science, very different from sitting in a laboratory or in front of a computer. Since then, I’ve been fortunate enough to sail to really remote and extraordinary places. Few scientific experiences can compare with that.
Q. At what point did you decide to dedicate your life to the ocean?
A. What initially attracted me to oceanography was precisely working at sea. It was an extraordinary experience, both from a scientific and a personal point of view. I soon had the opportunity to lead research expeditions with teams of 20 or 30 people. It was thrilling.
But, over time, I also came to understand the limitations of that method. I remember one of my last major expeditions: we sailed a ship from the United States to Cádiz… it took us about a month to cross the Atlantic. While we were sailing, I already knew that, by the time we reached Spain, the ocean we had begun to measure would no longer be the same. It had changed during the voyage. That made me realize that we were trying to describe a dynamic system as if it were a still photograph.
Q. What role does international cooperation play in the field of oceanography?
A. There are two fundamental ideas [to keep in mind]: the first is that the ocean is global… and so is the climate. You can’t understand the climate system without understanding the ocean.
The second is that this knowledge is only possible thanks to international cooperation. Some countries contribute instruments, others develop digital models, [while] others deploy scientific expeditions.
The great shift in the last 30 years has been the realization that the ocean doesn’t belong to a single nation. Rather, it’s a shared system.
Q. After almost half-a-century of researching the impact of climate change on the ocean, are you optimistic about our ability to address this crisis?
A. Based on observations from the last 35 years, we have a much better understanding of how complex the climate system is. [We know] that changes in some regions are very different from those occurring in others. I think we have a better understanding of the issues and a clearer description of the ocean [in its entirety]. The crucial question is whether we have genuine predictive capabilities… and that will depend on the timeframe that we’re considering.
The ocean tomorrow will be very similar to the ocean today. However, in 10 years, the ocean will be different. And, in 50 or 100 years, it will be even more [different]… but we’re not sure why. We also don’t know how it would evolve if left alone. And we don’t know how it will react or evolve with rising levels of carbon dioxide.
Q. Just a few months ago, Donald Trump stood before the UN and denied climate change. Will the political discourse that questions science, climate change and climate action have tangible consequences?
A. The consequences of Trump in the United States are terrible. A generation of scientists isn’t receiving funding for their research. They can’t find jobs. We’re denied funding [from the federal government because they argue that our research] is a hoax. This is an ignorant view of the chemical and physical principles that have been understood by science for over 100 years. It’s [been known for a long time] that carbon dioxide would warm the climate system.
Any serious scientist will tell you that they have no doubt that there’s a major problem at hand. We see it on a daily basis with the extreme weather events occurring around the world. This isn’t a hoax: this is exactly what was predicted decades ago.
Q. What role should scientists play in this context?
A. [We should] sound the alarm, something that the pioneers of climate change research began doing decades ago. The [other thing we need to do is understand] how the climate system works, how it’s changing and what risks we face. But there’s a very important difference between saying that something will happen for certain and saying that there’s a high probability of it happening. Science works with probabilities – not absolute certainties.
We know that sea levels will rise… but we cannot say exactly when, or to what extent it will affect each place. If someone announced that [your city] would be flooded next week, the reaction would be immediate. But if we point out that the risk exists in 100 years, some will say, “Well, that’s someone else’s problem.” This gap between science and society is a major challenge. Scientists must make it clear that there are real risks… even if the timetable remains uncertain.
Q. Could you mention a specific example of this?
A. We’re seeing it with forest fires. No one could predict the exact day they would occur… but we did know that the risk was increasing and that we had to prepare. The warnings were there; what was lacking was [a clear course of] action. Our job is to do the best science possible, clearly communicate the most likely scenarios, and help society prepare for them.
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