3 myths about the weather - Popular Science

Pompeii is a tale that you’ve probably heard before. It’s one of the most famous from the ancient Roman world: a deadly volcanic eruption that destroyed an entire city – now an eerie tourist site and archaeological treasure trove. But, while many of us vaguely know what happened when Vesuvius erupted in 79 AD, there’s still so much we could learn from this tragedy.

Mud from a fjord shows an Atlantic air pattern brought wetter, colder spells to southern Greenland, a clue to how its ice may fare. Greenland’s ice is shrinking as the planet warms. But in the island’s southwest, rainfall and snowfall have been influenced by the same North Atlantic air-pressure pattern for at least 5,000 years. When that pattern tipped one way, the region turned wetter and colder. The record comes from mud on the floor of a Greenland fjord, and it suggests snowfall, not only temperature, shaped how the area’s ice grew and shrank. It doesn’t yet show how glaciers there will respond to the warming ahead. Johan Faust, a researcher at MARUM, the Center for Marine Environmental Sciences at the University of Bremen in Germany, led the work with colleagues in Germany, Norway, Denmark and Canada. A seesaw in the airThe pattern is called the North Atlantic Oscillation. It’s the difference in air pressure between a low that sits near Iceland and a high near the Azores, and it’s strongest in winter. When that difference is large, the pattern is in its positive phase. Northwestern Europe and southwestern Greenland both get more rain and snow.