The latest climate modeling is raising big questions about the apparently Arctic-driven “new normal” weather that only a year ago and for years before looked to be transforming Anchorage into a version of Seattle north.
Some have theorized that warmer air over the Arctic is reshaping the polar jet stream in a way that increases its oscillations, pushing it deeper into the Pacific Ocean far to the west, and then driving it north across the Gulf of Alaska to push warm Pacific air into the 49th state’s underbelly to radically alter the nature of winter.
What has made big the news, however, is the next ripple in the flow that sees the push of warm air through Alaska chill out in the Arctic before swinging back into the North American midsection.
“Every time severe winter weather strikes the United States or Europe, reporters are fond of saying that global warming may be to blame,” Paul Voosen wrote last week at Science Magazine. “The paradox goes like this: As Arctic sea ice melts and the polar atmosphere warms, the swirling winds that confine cold Arctic air weaken, letting it spill farther south.”
In a story that started off mocking then-President Donald Trump for Tweeting, possibly in jest, that windchill temperatures of 60 degrees below zero left him wondering “What the hell is going on with Global warming? Please come back fast, we need you,” reporter Edward McClelland explained that the cold air could be traced back to global warming in the Arctic.
“Eastern North America is one of the few places getting colder in the winters. On the map for New Year’s Day, 2018, when the temperature in Chicago hit six below zero, there was a deep blue blotch above the United States, indicating temperatures up to ten degrees below normal,” he wrote.
“The reason can be traced to the Arctic, which is warming twice as quickly as the rest of the world. Warmer air weakens the jet stream, which ordinarily traps Arctic air at the top of the world.”
The winters have been colder in the Midwestern and Eastern years in recent years, and it was theorized that the warmer Arctic was to blame for the shifts in the jet stream that caused this.
But the latter connection is far from proven, and now the theory is the subject of new debate. This is how science works.
Science is seldom simple given that it is not a belief – like religion – but a method for figuring out how things work. Unfortunately, too, scientists are often left to try to sort out a jigsaw puzzle with a lot of missing pieces.
Yes, some science is simple. If you want to know if hitting yourself in the head with a hammer hurts, you can conduct an experiment.
You can take the two variables: The hammer and your head, and bang the latter with the former and record the results. Odds are it will hurt.
Still, you can make the experiment more interesting by adding some variables.
Say a wool hat underneath the helmet, and then maybe some bubble wrap over the hat underneath the helmet, and then a foam pad over the bubble wrap over the hat underneath the helmet, and etc.
String this out far enough, and you might even be able to get to the point where you can conclude that hitting yourself in the head with a hammer doesn’t hurt under certain circumstances.
Unless, of course, you’re one of those with a head so hard the first whack with the hammer on your bare noggin didn’t hurt. Then you can simply conclude, hitting yourself in the head with a hammer is painless, which is sure to fuel pushback.
Because that is how science works.
In real life, it invariably gets complicated. The problem scientists inevitably run into, especially when studying complicated natural phenomena like climate change, salmon survival, the spread of SARS-CoV-2, the dangers of obesity and more is that there are so many variables in play, a real and always lingering danger of confirmation bias, and a bad human inclination to look at the short term versus the long term.
Especially when it comes to studying natural global functions, a change that looks significant on a 10-year time scale can, for instance, disappear into the normal variations of change operating on a 100-year time scale.
Thus the climate can be seen to have been cooling in the Central Alaska city of Fairbanks as the 20th century was drawing to a close and the 21st century was beginning, as seen for the years 1979 to 2009 in the graphic below:
But when the timeline is changed from a 10-year-scale to a 100-year scale, the 30-year cooling becomes a 100-year warming as in this chart:
What the trend might look like over the past 500 years is unknown, but that best linear fit could prove to be something else again.
Note the dot for the year 1926, the warmest in Fairbanks history, that came only eight years after the coldest. This is the kind of variability that made the researchers at the University of Exeter pour cold water on the idea the so-called “Arctic amplification” has been powering those Lower 48 cold snaps that generally run counter to Alaska’s big thaws.
When the Exeter researchers pumped a lot of data into the university’s Polar Amplification Model Intercomparison Project, they found it showed little weakening of the polar jet stream as the Arctic warmed.
James Screen, a climate scientist there, last month told the annual meeting of the European Geosciences Union that even with far more of the Arctic Ocean ice-free than it is today, the model indicates the polar jet stream would still only weaken enough to allow a shift in swings of 10 percent or less.
In the view of Screen and colleague Russell Blackport, the loss of sea ice to date hasn’t been enough to do much of anything.
“To say the loss of sea ice has an effect over a particular extreme event, or even over the last 20 years, is a stretch,” Voosen quoted Screen as saying.
In a paper published in the Journal of Climate in February, Screen and Blackport wrote that the problem of normal climate variability in the Arctic makes it difficult to disentangle possible long-term changes from what has gone on in the past few decades.
When winter sea ice conditions in the Chukchi and Bering seas along Alaska’s western coast are compared to North American surface air temperatures, they wrote, the “the strength and sign of the connections both vary considerably between individual 35-year-long ensemble members, highlighting the need for large ensembles to separate robust connections from internal variability.
“(But) we conclude that the causal effects of sea ice variability on mid-latitude winter climate are much weaker than suggested by (current) statistical associations….”
But then again, science.
Screen and Blackport could be wrong, and the warming arctic could indeed be playing havoc with the weather all across the northern hemisphere. Time will tell.
A winding road
This is science. It seldom runs directly from point A to point Z.
What we are so sure of today can be changed significantly by what we learn tomorrow. It was “known” by the medical wizards of 1345 that the Black Death, a threat to human health that made today’s pandemic look like little, was caused by a “great pestilence in the air.”
This stemmed from the miasma theory, which held that a whole lot of diseases were caused simply by “bad air.”
We now know that the ancients were wrong while being a little bit right. The U.S. Centers for Disease Control earlier this month – after months of blaming SARS-CoV-2 infections primarily on human spittle ( can you say “droplets?”) – finally accepted that the virus that causes sometimes deadly COVID-19 can become a pestilent in the air.
The Black Death, however, is now generally believed to have been caused by a bacteria carried by rats – not anything in the air.
“Once a flea bites a rat infected with plague, the pathogen Y. pestis grows in its gut,” writes Wynne Parry at Live Science long before the new pandemic began. “After about two weeks, the bacteria block the valve that opens into the flea’s stomach. The starving flea then bites its host, by now probably a new, healthy rat or a person, more aggressively in an attempt to feed. All the while, the flea tries to clear out the bacterial obstruction and so regurgitates the pathogen onto the bite wounds.”
It was this pathogen that was thought to have claimed the lives of a third of the residents of Europe 660 years ago, and then faded but continued to hold on to this day, according to the World Health Organization (WHO).
“From 2010 to 2015, there were 3248 cases reported worldwide, including 584 deaths,” WHO reports, but the modern plague is nowhere near as deadly as the ancient plague.
That has led some scientists to question if the plague was really the only disease roaring through Europe in the 14th century and whether rats were truly to blame.
In a study published by the Proceedings of the National Academy of Sciences of the United States in 2017, scientists came to the defense of the rats, arguing the plague moved too rapidly and too widely to have been spread by rodents.
But some other scientists have questioned whether there was only a bacteria doing all the killing. Two epidemiologists from Liverpool University 20 years ago authored a book suggesting Europe might have been devasted by an unknown virus similar to Ebola.
“The most obvious problem with the plague theory is that, unlike bubonic plague, the Black Death obviously spread directly from person to person,” Debora Mackenzie wrote at New Scientist after the book was published. “People in the thick of the epidemic recognized this, and (Susan) Scott and (Christopher) Duncan proved they were right by tracing the anatomy of outbreaks, person by person, using English burial records from the 16th century. These records, which detail all deaths from the pestilence by order of Elizabeth I, clearly show the disease spreading from one person to their neighbors and relatives, separated by an incubation period of 20 to 30 days.
“The details tally perfectly with a disease that kills about 37 days after infection. For the first 10 to 12 days, you weren’t infectious. Then for 20 to 22 days, you were.
“You only knew you were infected when you fell ill, for the final five days or less, but by then you had been infecting people unknowingly for weeks. Europeans at the time clearly knew the disease had a long, infectious incubation period, because they rapidly imposed measures to isolate potential carriers. For example, they stopped anyone arriving on a ship from disembarking for 40 days, or quarantina in Italian – -the origin of the word quarantine.”
The theory put forth by Scott and Duncan didn’t gain much traction among scientists in 2001. But why would it?
Who would ever have thought a deadly disease spread widely by asymptomatic or presymptomatic individuals could get in the air and kill millions?