Study: Warming Halted Early Growth of a Possible New Glacial Period in Arctic Canada
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Researchers report that an ice cap in northern Canada began expanding about 2,000 years ago, which they argue marked the start of Earth's next glacial period. By the 1960s, warmer summers had reversed the growth.
A study published in Science reports that an ice cap in northern Canada began growing about 2,000 years ago. The researchers argue this marked the beginning of Earth's next glacial period. By the 1960s, warmer summers had reversed the process and the ice was retreating.
The team, including Lamont-Doherty Earth Observatory geochemists Nicolás Young and Joerg Schaefer, studied the Barnes Ice Cap on Baffin Island in Nunavut. It is roughly the size of Delaware and is the surviving remnant of the Laurentide Ice Sheet, which covered much of Canada and the northern United States from about 95,000 to 20,000 years ago.
Because the Barnes Ice Cap is frozen to its bedrock, it buried plants as it grew rather than scraping them away. Its retreat since 1960 has exposed them. The researchers dated the plants with carbon-14 to track when the ice advanced over them. Combining these samples with plants from nearby smaller ice caps, they concluded that the Laurentide reached its smallest extent about 3,000 years ago, and that conditions became cold enough for ice to build up again roughly 1,000 years later.
The authors propose that this first renewed growth should count as the start of a glacial period. Young says the process would have been far too slow to change the climate within a human lifetime, and that rebuilding the Laurentide's continental reach would have taken about 30,000 years. Models project the Barnes Ice Cap will melt completely within the next few centuries. Scientists cannot say when another glaciation might begin.
