Study: Fossil Fuel Emissions Halted a Nascent Ice Age and Reversed 2,000 Years of Ice Growth

Research published Thursday in Science concludes that carbon pollution has already reversed millennia of ice-cap expansion on Canada's Baffin Island. The Barnes Ice Cap, a Delaware-sized remnant of the Laurentide Ice Sheet that once stretched from Canada to New York and the Midwest, began regrowing roughly 2,000 years ago — possibly the opening of a new glaciation — then began shrinking in the 1960s as emissions climbed. Lead author Nicolás Young, a paleoclimatologist at Columbia University's Lamont-Doherty Earth Observatory, says modern retreat has undone 2,000 years of net expansion. Using Beryllium-10 exposure dating on rocks near the ice edge, the team calculated the cap first reached its present size about 3,600 years ago; preserved dead mosses later overrun by ice tracked its re-expansion. Aerial photographs show edges pulling back an average of 4 meters annually since the 1980s. Andrew Wickert of the University of Minnesota Twin Cities, who was not involved, called the finding significant. Dartmouth's Meredith Kelly praised the data but sought comparisons with other global sites. Young notes the work may also vindicate a 1970s Brown University meeting whose participants warned President Richard Nixon of an imminent glaciation.