Kink in the Jet Stream and Climate Change Spur Extreme Weather
Kinked, buckled, stuck or stalled, it doesn’t matter how you describe it, the jet stream -- the ribbon of wind that circles the Earth -- is doing strange things.
The calamity list includes wildfires across Scandinavia, Greece and California, record heat in Texas, Japan and Africa and flooding rains along the U.S. East Coast that could last another week. The world is hotter in general, which means when temperatures spike, they do so off a higher baseline.
“We are seeing some extreme jet-stream behavior, where the jet stream is contorting into these extreme loops both sharply towards the poles with ridges of high pressure and dips to the equator with troughs of low pressure,’’ said Jeff Masters, co-founder of Weather Underground in Ann Arbor, Michigan. “The extreme configuration is getting stuck in place which means that places are getting long periods of extreme weather.’’
Burnt automobile line the streets following a wildfire east of Athens, on July 25. Photographer: Yorgos Karahalis/Bloomberg
Globally, at least 170 people have died in fires, floods and heat on three continents. Electric markets around the world -- and the coal and natural gas that generate the power -- have spiked as days of high temperatures through Asia, North America and Europe continue to mount and weary residents turn to air conditioning to keep their misery at bay.
In California, parts of Yosemite National Park were closed and visitors told to flee as a fire rages in the forests and mountains, according to the California Department of Forestry and Fire Protection, also known as Cal Fire. The blaze, called the Ferguson Fire, has killed at least one person, consumed more than 38,000 acres and is about 25 percent contained. Smoke from the fires has caused an air-quality alert to be posted in the mountains and foothills of central California, according to the National Weather Service.
Temperature records were shattered in Japan when readings reached 106 degrees Fahrenheit (41 Celsius); Waco, Texas, hit an all-time high of 114; and Finnish Lapland touched a new mark.
The situation in Scandinavia has been “pretty mind boggling,’’ with the Baltic Sea water rising to 15 degrees above average and Lapland north of the Arctic Circle reaching the 90s, Masters said. “That is really eye catching sort of heat.’’
Earlier in July, Ouargla, Algeria hit 124.3 degrees, which is the highest temperature recorded in Africa, said Kevin Trenberth, distinguished senior scientist at the National Center for Atmospheric Research in Boulder, Colorado. California and the U.S. Southwest have also had a string of temperatures at or near 120 this July.
“In very arid conditions, those sort of things are possible and we are seeing more of them in different places around the world,’’ Trenberth said.
Science will need time to study if this extra-hot summer is because of climate change or bad luck for those baking, soaking and choking, but this is what global warming would look like. The exact cause of why the blocking in the atmosphere got going this July might require a bit of study too, said Greg Carbin, branch chief at the U.S. Weather Prediction Center in College Park, Maryland.
“Everything is backed up,’’ Carbin said. “And it is global.’’
High on Carbin’s list of potential suspects, but not the only possible perpetrator, is a large high-pressure system lazily spinning clockwise in the western Atlantic Ocean, dominating the basin, and leaving weather patterns backed up like cars stuck in rush hour traffic. On top of that, there is a trough over the Bering Sea, a deep area of low pressure, that is helping keep the U.S. Southwest hot.
“It is really a chicken-and-egg thing,’’ Carbin said. “It is really hard in the atmosphere to know what came first because everything is so interconnected.’’
Climate scientists say they have high confidence that human-driven warming is a part of the heat waves, simply because the composition of the atmosphere has changed so dramatically in the last generation or two.
“It is important to know that any heat wave has both natural and now, human causes,” said Michael Wehner, a senior staff scientist at Lawrence Berkeley National Laboratory. “So in plain language, climate change simply makes these heat waves hotter than they would have been otherwise.”
Researchers today also need much less time than they did in previous years to determine the extent of any human influence on weird weather. The World Weather Attribution project, an international collaboration of scientists, expects to have its first analysis of the European heat wave published by the end of the week. Previous work -- on a 2014 European heat wave -- concluded that such an event was 35 times more likely than it would have been without warming.
Meanwhile, computer forecast models show few changes to the current weather. What this means is, if it is hot where you are, it will probably stay that way. If it is raining, get used to it.