Wallace S. Broecker (Chicago, United States; 1931-2019) earned his PhD in Geology in 1958 from Columbia University, an institution he remained associated with for the rest of his career. Newberry Professor of Geology in the Department of Earth and Environmental Sciences, he was also a scientist at Columbia’s Lamont-Doherty Earth Observatory, and an Academic Committee member of its Earth Institute.
Among the many recognitions he earned for his contributions to the science of climate change are the Vetlesen Prize (1987), the National Medal of Science from the U.S. government (1996), the b (2002) and the Crafoord Prize (2006). He is author of eleven books and over 500 published papers, in one of which he coined the term “global warming” (“Climate Change: Are We on the Brink of a Pronounced Global Warming?” Science, 1975).
He was a member of the U.S. National Academy of Sciences, the American Academy of Arts and Sciences, the American Geophysical Union, the European Geophysical Union and the UK’s Royal Society.
Speech
Climate Change, 1st edition
“In all these years in science I have learned that when you get an idea, it’s a bit like walking through the mist. You think you can see something coming towards you: you have a vague idea of what it is but you can’t describe it in any real detail.” This is Wallace S. Broecker describing his thought processes just as he was poised to make one of the most astonishing and visionary predictions in modern science. In 1975, one year before the first tentative signs of climate change, Broecker warned of imminent warming in an article published in the prestigious journal Science . The title he chose was “Climate Change: Are We on the Brink of a Pronounced Global Warming?” thus coining a term that would come to attain a scientific, social, economic and political importance he could never have imagined.
The story that led to Broecker’s prediction had all the ingredients of the best scientific mysteries: the spark of curiosity, sifting of the available information, perhaps a dash of intuition … and asking the right questions. “What concerned me at the time was why we were not noticing the warming process, when all the models were telling us it had to be there, due to the increased concentration of carbon dioxide (CO2) in the Earth’s atmosphere. Yet three decades had gone by with practically no alteration. How could that be?” After analyzing data on the climate changes of the past, Broecker’s conclusion was that the cooling phase the climate was then undergoing had “more than offset” the CO2 effect. And he warned that when this natural cooling had run its course, “the exponential growth in atmospheric CO2 will begin to be a significant factor,” to the extent that “by the start of next century it will have caused average temperatures to rise beyond anything experienced in the last thousand years.”
Prophetic? The fact is that “Broecker’s warning” – as some have called it – may have found few listeners had it not come from a scientist of such wide repute.
Wallace S. Broecker is a professor in the Earth and Environmental Sciences Department at Columbia University (New York). He has published around 400 scientific papers and numerous books on the subject of climate change and, at the age of 77, continues to engage in front-line research. But his reputation was forged as long as five decades ago.
At the start of the sixties, Broecker pioneered the study of air-sea interaction, focusing on the exchange of gases such as CO2 . He was also the first to explore how the ocean’s absorption of atmospheric CO2 gives it a key role in global temperature regulation. His book Tracers in the Sea, published in 1982, inspired a whole generation of young researchers, not just for its content – an incisive and revealing study on the oceanic distribution of CO2 and various nutrients – but also for its author’s skill as a conveyer of knowledge.
Broecker’s research also paved the way for another major finding: the fact that the Earth’s climate can change abruptly in very short periods, at times less than twenty years. We now know – after what marks an important paradigm shift from traditional views about terrestrial climate changes – that certain processes can trigger extreme and sudden upheavals in the climate system. Today’s rapid thawing of the Arctic polar cap is a good example: increased freshwater inflow to the oceans causes changes in salinity which threaten to alter the main current distributing heat across the ocean basins: the thermohaline circulation. And the disruption of this oceanic heat conveyor belt could well unleash drastic changes in our global climate.
But Broecker is not one for facile alarmism: “We are still unsure about the tipping points for these abrupt changes, so are no position to make predictions.” An example of scientific caution which gives added weight to his vision of the future. What will happen next? How is society reacting to the evidence of climate change? In this respect, Prof. Broecker confesses himself “a little disappointed that we haven’t taken stronger actions. It has taken a lot of time to convince citizens in almost every country that this is a very serious problem.”
What we can say with certainty, in Broecker’s opinion, is that the planet will change. Rainfall patterns will alter, with the result that arid zones will become even drier. The landscape will change, because plant species will have to migrate to cooler regions to escape extinction. The shortage of water, and the social and political conflicts it gives rise to, will be one of the biggest problems facing society. What will not change is our relationship with fossil fuels. “We will continue to depend on them, meaning CO2 emissions are bound to increase, because renewable energies will not suffice to replace them, especially in poor countries. We need to encourage renewables all we can, but I don’t think it will be enough,” Broecker concedes. “It may take another 50 years before they really take off, so we need a stop-gap solution.”
This “plan B” against global warming rests on the development of a technology still at the experimental stage: carbon sequestration and storage. “The idea is to find a supplement to renewable energies, not an alternative. But we need to set to work now on carbon sequestration. We need to learn how to do it in a way that doesn’t damage the environment and at an energy and economic cost that stands within the bounds of reason.”
Broecker is also an impassioned educator. Among the titles he has published for students, policy-makers, the business community and the general public are How to Build a Habitable Planet, A Business Executive’s Guide to Global Warming (2005), and, most recently, Fixing Climate: What Past Climate Changes Reveal about the Current Threat and How to Counter It.
Tomorrow’s climate change historians will undoubtedly place Wallace S. Broecker up there among the pioneers. And this makes him an obvious as well as worthy inaugural winner of the first international prize devoted to the issue: the BBVA Foundation Frontiers of Knowledge Award in Climate Change. In closing, a quote that shows how Wallace S. Broecker’s scientific spirit makes a challenge out of adversity: “The next hundred years will be very interesting. I’d love to be around to see them.”
