Ice sheet expansion may have started 2,000 years ago, but we canceled that

Key points

• A study published in Science suggests the Laurentide Ice Sheet began growing again about 2,000 years ago, after reaching its smallest size around 3,600 years ago. Researchers led by Nicolas Young studied Barnes Ice Cap on Baffin Island, the last surviving fragment of the Laurentide.
• Its frozen base preserved plants that the advancing ice later killed, allowing scientists to date the change.
• The team says the expansion was reversed around 1960 by human-caused warming, which has since left Barnes Ice Cap shrinking and expected to disappear within a few centuries.