Heatwaves around the world in recent years have been so intense that they cannot be explained by global warming alone, a new study claims.
Scientists in New York say unexplained heatwave ‘hotspots’ are popping up on every continent except Antarctica like ‘giant, angry skin blotches’.
Marked out on a new map, these 10 distinct heatwave regions are so extreme, they fall far beyond what any model of global warming can predict or explain.
They are located in central China, Japan and Korea, the Arabian peninsula, eastern Australia and north 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.
There’s even a heatwave ‘hotspot’ over the UK and northwest Europe, leading to lethal summer temperatures in 2022 and 2023.
‘These regions become temporary hothouses,’ said lead study author Kai Kornhuber, a research scientist at Columbia Climate School.
‘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. We’re not built for them, and we might not be able to adapt fast enough.’
Unexplained heatwave ‘hotspots’ are popping up across the globe, so extreme, they cannot be explained by global warming models
The UK and northwest Europe had a heatwave hotspot in June-July 2022. Europe also suffered a heatwave the following year
These ‘hotspots’ see repeated heatwaves cropping up in multiple summers – so even though temperatures cool down after the summer ends, they reappear in the same region again. Pictured, raging wildfires north of Bly, Oregon on July 17, 2021
The researchers do not argue against global warming as a concept, as evidence shows that it’s the cause of soaring temperatures.
Rather, their study identifies a new phenomenon – unexplained heatwave hotspots – that global warming can’t explain, meaning other factors are surely at play too.
‘This is about extreme trends that are the outcome of physical interactions we might not completely understand,’ added Kornhuber.
The study identifies areas of extreme heat over the past 65 years, where temperatures are accelerating considerably faster than anywhere else, leading to increasingly wild weather events, infrastructure damage and death.
These hotspots see repeated heatwaves cropping up in multiple summers.
So, even though temperatures cool down after the summer ends, they reappear in the same region again.
One hotspot is the US Pacific Northwest and southwestern Canada, which saw a nine-day heatwave starting in June 2021.
During this astonishing heat event, temperatures broke daily records in some locales by 54°F (30°C), while Canada’s highest ever temperature (121.3°F/49.6°C) was recorded in Lytton, British Columbia.
A nine-day heatwave hammered the US Pacific Northwest and southwestern Canada in June 2021 – described by researchers as a heat anomaly
The extreme 2021 heatwave struck the North American Pacific Northwest. Pictured, hot conditions in Portland, Oregon, June 26, 2021
The town burned to the ground the next day in a wildfire driven in large part by the drying of vegetation in the extraordinary heat.
Meanwhile, in Oregon and Washington state, hundreds of people died from heat stroke and other health conditions.
Another unexplained heatwave hotspot is an area in northwestern Europe covering several countries including Germany, France, the Netherlands and the UK.
In this hotspot, abnormally high temperatures caused 60,000 deaths in 2022 and 47,000 deaths in 2023.
In northern Europe, few people in this region have air conditioning because it is generally not needed, and this probably upped the death toll, the team say.
While the cause of heatwave hotspots is yet to be identified, one potential explanation involves the jet stream – the fast, narrow current of air flowing from west to east that encircles the globe.
As the Arctic is warming on average far more quickly than most other parts of the Earth, this appears to be destabilizing the jet stream.
This is causing the jet stream 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.
The heatwave hotspots are located in central China, Japan, Korea, the Arabian peninsula, eastern Australia and north Africa. Others include Canada’s Northwest Territories and its High Arctic islands, northern Greenland, the southern end of South America and Siberia
European nations including France, Italy, Spain, Germany and the UK faced one of the most dangerous periods of heat in the summer of 2022. Pictured, Hackney, east London on July 18, 2022
Jet streams are fast flowing, narrow currents of air that carry warm and cold air across the planet, much like the currents of a river
However, this is only one hypothesis, and it does not seem to explain all the extreme heatwave events of recent years.
The researchers conclude that extreme heat is increasing significantly and faster in magnitude than what state-of-the-art climate models have predicted.
Unprecedented climate impacts can cause huge damage infrastructure and ecosystems while threatening human life.
According to another recent study, there were at least 2,325 heat-related deaths in the US – more than double since 1999.
There’s now calls for heatwaves to be given names in the same way as hurricanes, to heighten public awareness and motivate governments to prepare.
‘Our findings highlight the need to better understand and model extreme heat and to rapidly mitigate greenhouse gas emissions to avoid further harm,’ the team say in their paper, published in Proceedings of the National Academy of Sciences.
Researchers have already named 2023 as Earth’s hottest recorded year ever, at 2.12°F (1.18°C) above the 20th-century average.
Last year’s global average temperature was 58.96°F (14.98°C), around 0.3°F (0.17°C) higher than the result in 2016, the previous hottest year.
2023 is confirmed as the warmest calendar year in global temperature data records going back to 1850. The global average air temperature was 58.96°F (14.98°C), around 0.3°F (0.17°C) higher than the result in 2016
The 10 hottest years on record have occurred in the past 15 years, according to the EU’s Copernicus Climate Change Service (C3S).
At the top of the list is 2023, followed by 2016 and then 2020, 2019, 2017, 2022, 2021, 2018, 2015 and 2010.
2024 has already recorded the hottest summer and hottest single day (July 21), but the records are not expected to stop there.
Experts have warned that 2024 is almost certainly going to be Earth’s warmest year on record, beating the record set by 2023.
‘After 10 months of 2024 it is now virtually certain that 2024 will be the warmest year on record and the first year of more than 1.5ºC above pre-industrial levels,’ said Samantha Burgess, deputy director of C3S.
