The term “global warming” appears for the first time in print on August 8, 1975, with the publication of Wallace Smith Broecker's paper “Climatic Change: Are We on the Brink of a Pronounced Global Warming?” in the journal Science . Five years earlier, in 1970, Broecker, a researcher at Columbia University's Lamont-Doherty Earth Observatory, published a study of ocean sediment cores that revealed the Ice Age had seen rapid transitions in its climate , with ice sheets taking tens of thousands of years to develop in freezing temperatures, followed by sudden warm periods that melted the ice. Broecker built on this discovery in his 1975 paper, which hypothesized that the Ice Age’s rapid fluctuations had been caused by changes in "thermohaline circulation": the ocean currents and wind systems that move heat from the equator up north towards the poles and transport cold water toward the equator. Broecker later named this the "Great Ocean Conveyor." He believed ...