Broecker was born on November 29, 1931, and grew up in Oak Park, Ill., the second of five children. Broecker’s parents, evangelical Christians, sent him to Wheaton College, a Christian liberal arts school. He planned to become an actuary, but a friend helped him land an internship at what became the Lamont-Doherty Earth Observatory (LDEO) at Columbia, where he fell in love with scientific instruments and carbon dating. Broecker transferred to the College and earned a bachelor’s in physics. In 1958, he earned a Ph.D. in geology from GSAS, and he joined the Columbia faculty in 1959. LDEO was Broecker’s academic home for 67 years; while there he worked with J. Laurence Kulp, a geochemist pioneering work on radiocarbon dating, which allowed researchers to determine the ages of materials as far back as 40,000 years.
Broecker was able to understand Earth’s climate system from research into its oceans, atmosphere, ice and more, and gave early warning of a potential planetary crisis. In 1975, he published the landmark scientific paper, “Climatic Change: Are We on the Brink of a Pronounced Global Warming?” He was fond of saying, “The climate system is an angry beast, and we are poking it with sticks.”
Broecker noted that while the global climate had been experiencing a natural cycle of cooling, planetary temperatures would soon begin to rise because of the accumulation of carbon dioxide in the atmosphere. In 1976, they did; however, he had based his predictions on a simplified model of the climate system. In 2017, he wrote a follow-up paper stating that, as accurate as his prediction turned out to be, “It was dumb luck.”
The author of more than 500 research papers and at least 17 books, many self-published, Broecker sought not only to warn the world about the risks of climate change, but also to propose solutions. He argued before Congress about the reduction of fossil fuels, and received honors and awards from foundations, governments and scientific societies, as well as honorary degrees from universities. Broecker was elected to London’s Royal Society and the U.S. National Academy of Sciences. In 1996, he received the National Medal of Science from President Clinton, and in in 2004, the GSAS Dean’s Award.
Broecker married Grace Carder in 1952; she died in 2007. Five of their six children survive him: Sandra, Cynthia Kennedy, Kathleen Wilson, Cheryl Keyes and Scott, as do his children from another relationship, Milena Hoegsberg ’04 and Tobias Hoegsberg. He was predeceased by a daughter, Suzanne. In 2009, Broecker married Elizabeth Clark; she survives him, as do his sisters Judith Redekop and Bonnie Chapin; seven grandchildren; and seven great-grandchildren.
Memorial contributions may be made to Lamont-Doherty Earth Observatory Development Office, 61 Route 9W, Palisades, NY 10964; lamont.givenow.columbia.edu. Per Broecker’s wishes, his colleague Sidney R. Hemming will scatter his ashes at sea on an upcoming research trip.
— Lisa Palladino