Wallace Broecker, a geochemist with an almost 67-year career at Columbia University’s Lamont-Doherty Earth Observatory and a member of the National Academy of Sciences, died yesterday (February 18) in New York. He was 87 years old.
Broecker’s research helped develop scientists’ current understanding of ocean circulation and its role in global climate.
“Wally was unique, brilliant and combative,” Michael Oppenheimer of Princeton University tells the Associated Press. “He wasn’t fooled by the cooling of the 1970s. He saw clearly the unprecedented warming now playing out and made his views clear, even when few were willing to listen,” he says.
Broecker was born in Chicago and grew up in the suburb of Oak Park, Illinois. Although he considered a career as an actuary while studying at Wheaton College in Illinois, his plans changed after an internship in 1952 at Lamont Geological Observatory, now Lamont-Doherty Earth Observatory (LDEO), where he worked on radiocarbon dating, a new method at the time. After the internship, he transferred to Columbia University, completing his undergraduate degree in physics and staying on to earn a PhD in geology in 1958. Broecker joined Columbia’s faculty in 1959.
In the 1970s, Broecker co-led a program that mapped the circulation of water in the deep ocean and gas exchange between the ocean and the atmosphere by analyzing trace metals, radioisotopes, and nutrients. His work showed that water circulated between shallow and deep areas of ocean on the scale of centuries rather than tens of thousands of years, as was previously thought.
In the 1980s, Broecker put forth a view of currents in the world’s oceans that he called “The Great Ocean Conveyer.” In his conception, shallow water flowed from the warm south Pacific, through the Indian Ocean, around Africa, through the Atlantic, and up to the Arctic. There, the water cooled and sunk, eventually looping back in the deep to the Pacific where it would warm, rise, and begin the cycle again. Broecker argued that because of its scale, the conveyer plays a role in global climate by moving heat around the planet; his idea became the consensus view.
Broecker also influenced our understanding of climate and even the language we use to describe it. In 1975, he published an article in Science summarizing his and others’ research and arguing that the anthropogenic release of carbon dioxide would warm the earth’s climate. This was said to be first time the words “climate change” were used in a scientific paper to describe the phenomenon. He got the general picture right, although he incorrectly interpreted some of the ice core data, according to an obituary by the Earth Institute at Columbia University.
Broecker mentored around 50 graduate students at LDEO and “was known for his friendly demeanor, but also for his bluntness and volcanic temper; he publicly skewered grad students and senior scientists alike for sloppy work,” according to the Earth Institute obituary.
Broecker published around 500 research articles and 17 books. While also contributing to climate research, he communicated the geological understanding of climate change to government leaders. He briefed politicians on the subject in 1980s, testifying before congress in 1984 and continuing to discuss the topic with leaders in the following years.
Broecker was awarded numerous honors and awards by foundations and scientific societies. He was elected to the US National Academy of Sciences in 1977. In 1996, President Bill Clinton awarded Broecker the National Medal of Science.
“His discoveries were fundamental to interpreting Earth’s climate history,” Oppenheimer tells the AP. “No scientist was more stimulating to engage with: he was an instigator in a good way, willing to press unpopular ideas, like lofting particles to offset climate change. But it was always a two-way conversation, never dull, always educational. I’ll miss him.”