The history of Greenland's snowfall is chronicled in an unlikely place: the remains of aquatic plants that died long ago, collecting at the bottom of lakes in horizontal layers that document the passing years. Using this ancient record, scientists have determined that snowfall at one key location in western Greenland may have intensified from 6,000 to 4,000 years ago, a period when the planet's Northern Hemisphere was warmer than it is today.

Source: A history of snowfall on Greenland, hidden in ancient leaf waxes