Giant 'waves' in the sky wreak havoc on our weather, study says
[USA Today] 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 Mann of 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.
The extreme and unusual jet stream patterns – known technically as "quasi-resonant amplification" – could increase by as much as 50 percent by 2100, the study said.
A wild card in this theory is that another human-caused ingredient – air pollution – could actually counteract the impact of global warming on our atmosphere. This happens because the pollutants reflect sunlight back into space, keeping Earth cooler.
Daniel Swain, a climate scientist at UCLA and the National Center for Atmospheric Research who was not involved with the new research, told Inside Climate News the study has some "compelling new evidence on the link between amplified Arctic warming and extreme mid-latitude weather during the summer months."
As far as what to do about our warming planet, the song remains the same: "The future is still very much in our hands when it comes to dangerous and damaging summer weather extremes," Mann said. "It's simply a matter of our willpower to transition quickly from fossil fuels to renewable energy."
The study appeared in the journal Science Advances.