A New Ice Age Was Beginning. Then Humans Started Burning Fossil Fuels

Researchers found that the Barnes Ice Cap on Canada’s Baffin Island began growing again about 2,000 years ago, potentially signalling the start of another glaciation period. Since the 1960s, however, it has shrunk as carbon emissions have risen, showing how human-caused warming has reversed a long period of ice growth.

The team dated exposed rocks using beryllium-10 and examined preserved moss and lichen to reconstruct the ice cap’s history. Their findings suggest it reached its modern size around 3,600 years ago; since the 1980s, its edges have retreated by an average of four metres a year. Researchers say further comparisons with other sites could clarify how the planet’s natural climate cycles were developing before human warming.