Giant waves up there in the atmosphere have a huge influence on our weather down here.
The waves aren't water, they're strong "jet stream" winds that a new study says act strangely because of human-caused global warming. This, in turn, appears to cause more wild and extreme summertime weather for us Earthlings – and could increase in the decades ahead.
In summer 2018, for instance, impacts on extreme weather due to the weird behavior of jet stream winds were felt worldwide, according to study lead author Michael Mannof Penn State University.
"It played out in real time on our television screens and newspaper headlines in the form of an unprecedented hemisphere-wide pattern of extreme floods, droughts, heat waves and wildfires," Mann said.
What's happening, on a very basic level, is that unusual warmth in the Arctic causes jet streams – the rivers of air in the atmosphere that push and pull our weather around – to slow down, stall or meander in strange ways. When the undulations of the jet stream lock in place, weather systems can be trapped and cause havoc down here.
"If the same weather persists for weeks on end in one region, then sunny days can turn into a serious heat wave and drought, and lasting rains can lead to flooding," said study co-author Stefan Rahmstorf of the Potsdam Institute for Climate Impact Research in Germany.