Researchers have discovered a pattern of extreme heat waves that defy current climate models, occurring globally except in Antarctica, causing widespread fatalities and environmental damage.
The year 2023 was Earth’s warmest year on record, with an average temperature 2.12 degrees F above the 20th-century average. This surpassed the previous record set in 2016. Notably, the ten hottest yearly average temperatures have all occurred in the past decade. Furthermore, with the hottest summer and hottest single day, 2024 is on track to set yet another record.
Emergence of Extreme Heat Waves
While the continuous rise in global temperatures may not come as breaking news to some, an alarming phenomenon is emerging: certain regions are experiencing repeated heat waves that are so extreme they exceed the predictions and explanations provided by any existing models of global warming.
A recent study provides the first worldwide map of such regions, which appear on every continent except Antarctica like giant, angry skin blotches. In recent years, these heat waves have killed tens of thousands of people, withered crops and forests, and sparked devastating wildfires.
Analysis of Regional Heat Extremes
“The large and unexpected margins by which recent regional-scale extremes have broken earlier records have raised questions about the degree to which climate models can provide adequate estimates of relations between global mean temperature changes and regional climate risks,” says the study.
“This is about extreme trends that are the outcome of physical interactions we might not completely understand,” said lead author Kai Kornhuber, an adjunct scientist at the Columbia Climate School’s Lamont-Doherty Earth Observatory. “These regions become temporary hothouses.” Kornhuber is also a senior research scholar at the International Institute for Applied Systems Analysis in Austria.
A Global Survey of Accelerating Heat Waves
The study, recently published in Proceedings of the National Academy of Sciences, looks at heat waves over the past 65 years, identifying areas where extreme heat is accelerating considerably faster than more moderate temperatures. This often results in maximum temperatures that have been repeatedly broken by outsize, sometimes astonishing, amounts. For instance, a nine-day wave that hammered the U.S. Pacific Northwest and southwestern Canada in June 2021 broke daily records in some locales by 30 degrees C, or 54 F. This included the highest ever temperature recorded in Canada, 121.3 F, in Lytton, British Columbia. The town burned to the ground the next day in a wildfire driven largely by the drying of vegetation in the extraordinary heat. In Oregon and Washington state, hundreds of people died from heat stroke and other health conditions.
Extreme Heat Impact Across Continents
These extreme heat waves have been hitting predominantly in the last five years or so, though some occurred in the early 2000s or before. The most hard-hit regions include populous central China, Japan, Korea, the Arabian peninsula, eastern Australia, and scattered parts of Africa. Others include Canada’s Northwest Territories and its High Arctic islands, northern Greenland, the southern end of South America, and scattered patches of Siberia. Areas of Texas and New Mexico appear on the map, though they are not at the most extreme end.
Vulnerable Regions in Europe
According to the report, the most intense and consistent signal comes from northwestern Europe, where sequences of heat waves contributed to some 60,000 deaths in 2022 and 47,000 deaths in 2023. These occurred across Germany, France, the United Kingdom, the Netherlands, and other countries. Here, in recent years, the hottest days of the year are warming twice as fast as the summer mean temperatures. The region is especially vulnerable in part because, unlike places like the United States, few people have air conditioning because traditionally, it was almost never needed. The outbreaks have continued; as recently as this September, new maximum temperature records were set in Austria, France, Hungary, Slovenia, Norway, and Sweden.
Contrasting Regional Temperature Trends
The researchers call the statistical trends “tail-widening”―that is, the anomalous occurrence of temperatures at the far upper end, or beyond, anything that would be expected with simple upward shifts in mean summer temperatures. However, the phenomenon is not happening everywhere; the study shows that maximum temperatures across many other regions are actually lower than what models would predict. These include wide areas of the north-central United States and south-central Canada, interior parts of South America, much of Siberia, northern Africa, and northern Australia. Heat is also increasing in these regions, but the extremes are increasing at a similar or lower speed than what changes in average would suggest.
Potential Causes of Extreme Heat Events
Climbing overall temperatures make heat waves more likely in many cases, but the causes of the extreme heat outbreaks are not entirely clear. In Europe and Russia, an earlier study led by Kornhuber blamed heat waves and droughts on wobbles in the jet stream, a fast-moving river of air that continuously circles the northern hemisphere. Hemmed in by historically frigid temperatures in the far north and much warmer ones further south, the jet stream generally confines itself to a narrow band. But the Arctic is warming on average far more quickly than most other parts of the Earth, and this appears to be destabilizing the jet stream, causing it to develop so-called Rossby waves, which suck hot air from the south and park it in temperate regions that normally do not see extreme heat for days or weeks at a time.
Investigating the 2021 Pacific Northwest Heat Wave
This is only one hypothesis, and it does not seem to explain all the extremes. A study of the fatal 2021 Pacific Northwest/southwestern Canada heat wave led by Lamont-Doherty graduate student Samuel Bartusek (also a coauthor on the latest paper) identified a confluence of factors. Some seemed connected to long-term climate change, others to chance. The study identified a disruption in the jet stream similar to the Rossby waves that were thought to affect Europe and Russia. It also found that decades of slowly rising temperatures had been drying out regional vegetation so that when a spell of hot weather came along, plants had fewer reserves of water to evaporate into the air, a process that helps moderate heat. A third factor: a series of smaller-scale atmospheric waves that gathered heat from the Pacific Ocean surface and transported it eastward onto land. Like Europe, few people in this region have air conditioning because it is generally not needed, and this probably upped the death toll.
The heat wave “was so extreme, it’s tempting to apply the label of a ‘black swan’ event, one that can’t be predicted,” said Bartusek. “But there’s a boundary between the totally unpredictable, the plausible and the totally expected that’s hard to categorize. I would call this more of a grey swan.”
The Need for Increased Awareness and Preparedness
While the wealthy United States is better prepared than many other places, excessive heat nevertheless kills more people than all other weather-related causes combined, including hurricanes, tornadoes, and floods. According to a study out this past August, the yearly death rate has more than doubled since 1999, with 2,325 heat-related deaths in 2023. This has recently led to calls for heat waves to be named, similar to hurricanes, in order to heighten public awareness and motivate governments to prepare.
“Due to their unprecedented nature, these heat waves are usually linked to very severe health impacts, and can be disastrous for agriculture, vegetation and infrastructure,” said Kornhuber. “We’re not built for them, and we might not be able to adapt fast enough.”
Reference: “Global emergence of regional heatwave hotspots outpaces climate model simulations” by Kai Kornhuber, Samuel Bartusek, Richard Seager, Hans Joachim Schellnhuber and Mingfang Ting, 26 November 2024, Proceedings of the National Academy of Sciences.
DOI: 10.1073/pnas.2411258121
Never miss a breakthrough: Join the SciTechDaily newsletter.
Follow us on Google and Google News.
13 Comments
“Researchers have discovered a pattern of extreme heat waves that defy current climate models, …”
In other words, the climate models are unreliable.
As modelling climate and its future includes a great many variables, no doubt many of which are interdepedent ,of course climate modelling is imprecise ( so termed unreliable) in detail. However, if CO2 and water vapour and cow farts are “greenhouse gases” and reliable measurements show that these are an increasing component of our atmosphere, something is gunna happen somewhere as overall the Earth warms up a tad. And if that warming and its less predictable consequences happen too quickly, then global civilisation is not going to be able to cope with those changes in an equable manner particularly so that there are 8.6 billion of us around, rather than 750 million of the early period of the industrial revolution when there was room for mass movement.
Quite when and how it all happens is one question, but it will be in a non-geological time-frame, and when the tough gets going, the tough generally drop bombs on others. And that is what we need to avoid; we need to adapt our global civilisation to impending changes, irrespective of whether specific predictions are 10, 25, 50 or 100 years in error. I doubt if good sense will prevail; generally it does not and that is the most frightening prediction of them all.
“However, if … reliable measurements show that these are an increasing component of our atmosphere, something is gunna happen somewhere as overall the Earth warms up a tad.”
Your unstated assumption is that there are no negative feedback loops — such as the (bi)carbonate buffering in the oceans — that counteract the increasing GH gases.
“…, of course climate modelling is imprecise (so termed unreliable) in detail.”
It is more than a matter of being imprecise, which implies a small error in the quantitative predictions. Sometimes the models predict the exact opposite for regional predictions, as in one model predicting drought and another model predicting flooding. I would say that is more than just imprecision when the predictions are contradictory. While the models predict warming, it might be a “spurious correlation” and the cause and effect might be reversed. One of the worst ‘sins’ in science is to be right for the wrong reason because inevitably one will be surprised by a Black Swan event.
Would you so cavalierly claim “of course doors will sometimes unpredictably fall off commercial aircraft,” or would you acknowledge manufacturing problems and demand efforts to eliminate such things?
Even the relatively straight forward predictions of temperatures from ensembles tend to run warm by an order of magnitude more than the uncertainty of the prediction.
As is often the case with ‘Climate Change,’ there are differences in opinion on the effects. This article, and NOAA, suggest that one should be concerned about heat-related deaths. Apparently, the CDC, which tracks US deaths based on death certificates, comes to a different conclusion. Should you be interested, you might find this linked article in Forbes to be of interest:
https://www.forbes.com/sites/joshuacohen/2023/07/19/excessive-summer-heat-can-kill-but-extreme-cold-causes-more-fatalities/
If anthropogenic global heating is leading to changes in patterns of atmospheric circulation, which might dump lots of snow on New York and Iowa, dead is dead whether one has died of either hypo-or hyperthermia.
Come on, Rob. You can do better than that! The article is about heat-deaths with no mention of cold. I’m pointing out that the one-sided presentation is giving the wrong impression to readers. Besides, your point about atmospheric circulation is unsupported speculation, NOT observed, measurable effects.
The magic non-scientfic word is “if”. If atmospheric circulation changes, then other things will change with it, or is that too naive a concept? One reads about jet streams doing interesting things that are common these days, and there is even a nice picture of jet stream doing high-amplitude meanders in a sinusoidal fashion (probably not precisely accurate but illustrative of the notion) which seem to have been unusual in most of our lifetimes but that affect local weather at various times of the year, some places getting flooded severely, some places getting overly hot and other places getting overly cold. A crude and imprecise generalisation, but dead is still precisely dead.
Yes, focusing on hyperthermia alone is indeed one-sided, but SciTech Daily generally prepares summary articles about what is a fairly narrow piece of research in a topic; in this case heat-waves. What’s the problem with commenting on the broader possible ramifications of that topic?
And back to the old canard. A vital part of scientific thought is underpinned by the words “if”, “might” , “could” and “would”. Those then lead to experimentation, modelling, further ifs mights coulds and woulds and yet more experimentation etc until at last we have probably undeniable truth that the Earth is not flat, does not rest on the back of a giant turtle and that Hubble’s observation of the red-shift defines the inconceivable notion that the entire universe must have expanded from a singularity of infinite density some many years ago, none of which could have existed previously.
“Those then lead to experimentation, modelling, …”
In an ideal world that is true. However, the media and some politicians are quick to use those ‘possibilities’ to justify major social changes without any good grasp of the probabilities. Those changes should wait until we have “undeniable truth” for the probabilities.
“One reads about jet streams doing interesting things that are common these days, …”
And you naively accept the claims as being valid because you read it on the internet?
Consider that with a common Gaussian probability distribution, events with low probability (tails on the distribution) happen randomly but infrequently. Over a long period of time, in order to fill in the tail populations, events that have not been observed before, become more probable. Assuming that the jet stream actually is behaving differently than in the recent past, it does not prove that warming is necessarily responsible. Look up “Rossby waves.”
https://www.britannica.com/science/jet-stream
https://www.britannica.com/science/Rossby-wave
Reality in general defies climate models, one way or the other.