Global heat wave hot spots outpace climate change trends
Add Axios as your preferred source to
see more of our stories on Google.
Illustration: Aïda Amer/Axios
Emerging research points out how much scientists have yet to learn about human-caused climate change — and raises the possibility that they, along with policymakers, are underestimating some risks lurking ahead.
Why it matters: The studies and media comments from scientists illustrate that the Earth's climate system — made up of the oceans, land and atmosphere — may no longer be behaving as it used to.
Driving the news: One recent study found emerging "hot spots" where heat waves are far outpacing global temperature trends.
- These places are defying predictions and can be found on each continent except Antarctica.
- Because of quirks of the jet stream and other reasons, the regional hot spots are seeing extreme heat events that have killed tens of thousands of people in recent years.
- Those events also have primed the environment for devastating wildfires and harmed crops.
The study, published in the journal Proceedings of the National Academy of Sciences, focuses on a newly identified known-unknown in climate science.
What they're saying: "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 and a researcher in Austria.
- "These regions become temporary hothouses," he said in a statement.
Zoom in: Kornhuber and his colleagues produced the first global map of these hothouse regions, showing how they emerged from records of heat waves stretching back to 1958.
- The areas on which they focused have seen maximum temperatures during heat waves far exceed previous records. One example occurred in Lytton, British Columbia, during the Pacific Northwest heat wave of 2021.
- The town set the record for the highest temperature on record in Canada that June, at 121.3°F. Most of the town then burned to the ground in a wildfire the next day.
Threat level: The study found extreme heat waves have become more common in about the past five years, particularly in parts of Asia, the Arabian peninsula, eastern Australia, Canada's far northern regions, northern Greenland and parts of Siberia.
- The strongest signal, though, comes from northwestern Europe, where the hottest days are warming twice as fast as the summer mean temperatures, the study found.
Between the lines: One hypothesis, which comes from Kornhuber's past work, is that the shifting temperature balance between the equator and the poles (the poles are warming at about three times the global rate) is altering the shape and persistence of jet stream patterns.
- This may be transporting hotter air further north and keeping it there for unusually long periods, trapped under slow-moving ridges of high pressure.
- But alterations in the jet stream are only one of several factors that may be at work. The study points out that such "extreme-extremes" aren't seen in research using the mean results from multiple climate models.
- The coauthors' clearest conclusion was to call for cuts to burning fossil fuels to reduce overall global warming and lower the likelihood of more severe hot spots emerging.
Other researchers are trying to account for the record global heat seen this year, which will eclipse 2023 as the hottest year on record.
- Writing on the Substack "The Climate Brink," climate scientist Zeke Hausfather shows that global average surface temperatures during the run-up to, during and post-period of the 2023-2024 El Niño event have departed from previous El Niño events.
- Such climate events, which feature unusually hot ocean temperatures in the eastern tropical Pacific Ocean, tend to elevate global average temperatures.
- However, the past few years — with two consecutive years of record-breaking global temperatures — have been exceptional.
- "Even looking at the longer record, the evolution of global surface temperatures both before and after the El Niño is unprecedented," Hausfather wrote last week.
"Temperatures rose earlier than we've seen before, and temperatures have remained at elevated levels for a longer period of time."
Yes, but: He did find that one El Niño event in 1958 showed a spike in global temperatures well after the El Niño conditions had dissipated, lending at least a bit of credibility to the possibility that natural climate variability is at play now.
Zoom out: Global efforts to limit warming to the Paris Agreement's temperature targets are faltering.
- There are increasing concerns that countries or wealthy individuals will turn to geoengineering, which would involve deliberately altering the planet's climate to hold warming at bay temporarily, as a risky stopgap.
- According to recent reporting in the New York Times, NOAA and the Energy Department are working on a detection system to be able to discern if any country or nongovernmental actor is pursuing such a plan.
The bottom line: All of these developments add up to a portrait of humanity entering a new, more turbulent stage of the era of climate consequences, where it may be getting more difficult to anticipate what may happen next.
