NOV 29, 2024 5:58 AM PST

Heat Wave Hotspots are Emerging in Unpredictable Ways

WRITTEN BY: Carmen Leitch

Scientists have already said that 2024 will be the hottest recorded year, and 2023 had already set a record for being 2.12°F above the 20th-century average. But there are also certain places on Earth that are experiencing expcetional warming that is outpacing averages and predictions significantly. Current climate models also do not offer any explanation for the anomalous warmth at these locations.

Burned trees along the trail into Hummingbird Saddle, Gila National Forest, New Mexico, where USGS scientists installed a rain gauge. / Credit: USGS / Photographer: Mike Sanders

Reporting in the Proceedings of the National Academy of Sciences (PNAS), scientists created a map of these regions, and there are places that fit the bill on every continent but Antarctica. In these areas in recent years, wildfires have devastated infrastructure and homes, forests and crops have perished, and tens of thousands of people have been killed as a consequence of this heat.

The study noted that this work has highlighted the limited ability of models to reliably estimate temperature changes and climate risks.

Regions where observed heat waves exceed trends from climate models. Boxed areas with the darkest red colors are the most extreme; lesser reds and oranges exceed models, but not by as much. Yellows roughly match models, while greens and blues are below what models would project.   Credit  Adapted from Kornhuber et al., PNAS 2024

"This is about extreme trends that are the outcome of physical interactions we might not completely understand," said lead study author Kai Kornhuber, an adjunct scientist at the Columbia Climate School, among other appointments. "These regions become temporary hothouses."

The study focused on places where extreme heat has led to repeated incidents of extreme temperatures that are breaking records by wide and sometimes shocking margins.

 

One example is the June 2021 heat wave that hammered the Pacific Northwest. Some temperature records were smashed by an astonishing 30°C, or 54°F. In Lytton, British Columbia, the highest recorded temperature in Canadian history was set, at 121.3°F (49.6°C). Lytton was destroyed by a wildfire the following day. Heat stroke and other health issues also killed hundreds of residents of Oregon and Washington.

Some other areas of exceptional warming include parts of Siberia, northern Greenland, the Arctic islands and Northwest Territories of Canada, portions of the Arabian Peninsula, parts of China, Japan, Korea, eastern Australia, and scattered areas in Africa.

But some of the most intense heating is consistently appearing in northwestern Europe. Sequences of heat waves there contributed in part to an estimated 60,000 deaths in 2022 and 47,000 deaths in 2023. The hottest temperatures are increasing twice as fast as summer mean temperatures there. Not many people have air conditioning in these areas either, because it has not been hot enough to justify it until now.

In contrast to this extreme warming are areas that are cooler than what some models predict. These include parts of northern Africa and Australia, some interior areas in South America, north-central United States and south-central Canada, and large parts of of Siberia.

Some climate scientists have suggested that wobbles in the jet stream could lead to heat waves and droughts, but that is only one potential explanation, and it does not account for all of these extremes.

This study also determined that jet stream wobbles may be contributing to this phenomenon. But questions remain.

"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."

Sources: Columbia Climate School, Proceedings of the National Academy of Sciences (PNAS)

About the Author
Bachelor's (BA/BS/Other)
Experienced research scientist and technical expert with authorships on over 30 peer-reviewed publications, traveler to over 70 countries, published photographer and internationally-exhibited painter, volunteer trained in disaster-response, CPR and DV counseling.
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