In 2023, Earth experienced its warmest year on record; temperatures rose 2.12 degrees Fahrenheit above the 20th century average, surpassing the previous record set in 2016. The hottest ten years occurred in the last decade. With 2024 already experiencing the hottest summer and one of the hottest days ever, it’s on track to break another alarming record.

excessive localized heat

While the steady increase in global average temperatures is no surprise to everyone, a striking new phenomenon is emerging: Some regions are experiencing extreme heat waves far beyond what any global warming model could predict or explain.

In a new study, researchers have created the first global map of regions experiencing unprecedented temperatures, appearing as huge, alarming hotspots on every continent except Antarctica. Heat waves in recent years have killed tens of thousands of people, devastated crops and forests, and sparked devastating fires.

“The large and unexpected extent to which recent extreme events at the regional scale have broken previous records has raised questions about the extent to which climate models can provide adequate predictions of the links between global mean temperature changes and regional climate risks,” the authors explain. .

ten years of heat

“These are extreme trends that are the result of physical interactions that we don’t fully understand,” said lead author Kai Kornhuber, a scientist at the Lamont-Dougherty Earth Observatory at Columbia Climate School. “These areas become temporary greenhouses.”

Researchers have studied heat waves over the past 65 years. It describes areas where extreme heat accelerates much faster than moderate temperatures, often resulting in record maximum temperatures of extraordinary magnitude. For example, a nine-day heat wave that hit the Pacific Northwest of the United States and southwestern Canada in June 2021 set daily records of as much as 30 degrees Celsius (54 degrees Fahrenheit) in some places.

This included the hottest temperature ever recorded in Canada, 121.3 F, in Lytton, British Columbia. Unfortunately, the next day the town was destroyed by a forest fire, caused mostly by vegetation wilted from the intense heat.

Regions affected by unprecedented heat

Hundreds of people died from heatstroke and other illnesses in Oregon and Washington states. These extreme heat waves have mostly occurred in the last five years, but some occurred in the early 2000s or earlier. The most affected areas include densely populated areas of Central China, Japan, Korea, the Arabian Peninsula, Eastern Australia and scattered parts of Africa.

Other areas affected include Canada’s Northwest Territories and High Arctic Islands, northern Greenland, the southern tip of South America, and scattered areas of Siberia. Parts of Texas and New Mexico also appear on the map, but they are not among the extreme areas.

Europe’s vulnerability to unprecedented temperatures

The most intense and consistent signals come from northwestern Europe, where successive heat waves are causing an estimated 60,000 deaths in 2022 and 47,000 in 2023, according to the report.

These events took place in Germany, France, England, the Netherlands and other countries. In recent years, the hottest days in the region have warmed at twice the rate of average summer temperatures. Europe is particularly vulnerable because, unlike places like the United States, few people have air conditioning due to its traditionally mild climate. Heat waves continue; As recently as this September, new maximum temperature records were set in Austria, France, Hungary, Slovenia, Norway and Sweden.

Researchers call these statistical trends “tail extension”; an unusual occurrence of temperatures at or even beyond the extreme upper limits that would be expected from simple fluctuations in average summer temperatures. However, this phenomenon is not universal; The study shows that maximum temperatures in many other regions are actually lower than models predict.

These areas include much of the north-central United States and south-central Canada, the interior of South America, much of Siberia, northern Africa, and northern Australia. As temperatures increase in these regions, extreme values ​​also increase at the same or lower rates than the average temperature changes would predict.

Causes of extreme temperature

A general increase in temperatures makes heat waves more likely in many cases, but the exact causes of these extreme heat events are not entirely clear. In Europe and Russia, previous research led by Kornhuber linked heat waves and droughts to fluctuations in the jet stream, a fast-moving airflow that orbits the northern hemisphere.

The jet stream, traditionally limited to a narrow band due to the temperature difference between the cold Arctic and warmer southern regions, is destabilizing as the Arctic warms faster than other parts of the world. This instability leads to the formation of Rossby waves, which draw warm air from the south and trap it in temperate regions unaccustomed to extreme heat for long periods of time.

However, this hypothesis does not explain all extreme events. A study of a deadly heat wave in the Pacific Northwest and Canada’s southwest in 2021 by Lamont-Doherty graduate student Samuel Bartusek (who also co-authored the final paper) found a combination of factors. Some were linked to long-term climate change, while others appeared to have occurred by chance. The study noted a jet stream disturbance similar to Rossby waves affecting Europe and Russia.

Ten years of warming

The researchers also found that gradually rising temperatures over decades dried out vegetation in the region, so when extreme temperatures hit, plants had less water to evaporate into the air, a process that helped lower temperatures. Another factor was a series of smaller atmospheric waves that carried heat eastward from the Pacific Ocean surface onto land. As in Europe, very few people in this region have air conditioning, possibly increasing the number of deaths.

“The heat wave was so extreme that it’s tempting to call it a black swan event, which is impossible to predict,” Bartusek said. “But there is a line between completely unpredictable, believable and completely expected that is difficult to classify. “I prefer to call it the gray swan.”

Increase in human casualties due to unprecedented heat

Even in wealthy countries like the United States, extreme heat remains the leading cause of weather-related deaths, surpassing tornadoes, tornadoes and floods. A study published last August found that the annual death rate has more than doubled since 1999, with the number of heat-related deaths reaching 2,325 in 2023. The worrying trend has led to calls for heatwaves to be labeled as hurricane-like to raise public awareness and encourage government preparedness.

“Due to their unprecedented nature, these heatwaves are often associated with very serious health consequences and can be disastrous for agriculture, vegetation and infrastructure. We are not built for them and may not be able to adapt quickly enough,” Kornhuber concluded. The study was published in the journal Proceedings of the National Academy of Sciences.