Global warming may have halted an emerging ice age, study suggests
Two thousand years ago, the Arctic remnants of a once-vast ice sheet started to grow again. It was the beginning of a new glacial period, more conversationally known as the next ice age—but by the 1960s, summer temperatures were already so high that the ice sheet started to shrink. In other words, global warming ended a period of glaciation that had already begun.
A new study suggests that global warming may have halted the onset of an emerging ice age. Two thousand years ago, remnants of a vast ice sheet started to grow again, signaling the beginning of a new glacial period, also known as the next ice age. However, by the 1960s, summer temperatures had already become so high that the ice sheet began to shrink.
This phenomenon, led by geochemists Nicolás Young and Joerg Schaefer, shows that global warming has disrupted what would have been the start of a new ice age. The Laurentide Ice Sheet, which once covered much of Canada and the northern United States, reached its smallest extent about 3,000 years ago before starting to expand again around 2,000 years ago.
This critical inflection point marks the beginning of Earth's next glacial period, contrary to previous model-based studies which suggested a much longer wait. The findings, published in Science, provide evidence that the next glaciation had already begun by the 1960s, challenging long-held beliefs about when these periods commence.
The disappearance of the Barnes Ice Cap, the last remnant of the Laurentide, could significantly alter the dynamics of future glaciations and ice ages, as it played a crucial role in initiating the cooling feedbacks that led to the growth of ice sheets.
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