A scorching heatwave that has gripped North America, claiming at least 125 lives in Mexico alone, was made significantly worse by climate change, according to a new study. The research, conducted by World Weather Attribution, a group of scientists specializing in rapid climate attribution studies, found that human-caused climate change increased the intensity of the heatwave by a substantial margin.
The study revealed that the sizzling daytime temperatures, which triggered cases of heat stroke in parts of the United States, were 1.4°C hotter due to the warming from burning coal, oil, and natural gas. The situation was even more severe at night, with climate change making nighttime temperatures 1.6°C warmer and unusual evening heat 200 times more likely. This lack of respite from the heat made the heatwave exceptionally dangerous, highlighting the critical role of cooler night temperatures in surviving such extreme events.
Mexico recorded its hottest ever temperature last week when temperatures in the Sonoran Desert hit 51.7°C, a stark reminder of the intensity of the heatwave. The study’s findings emphasize the growing threat of extreme heat events as global warming continues, with scientists warning that these events are becoming more frequent and intense. The alarming part is that this heatwave, which is still impacting the North American continent, is no longer considered a rare occurrence. Past studies by the group found that some heatwaves were impossible without climate change, but this heatwave was not so unusual from a weather perspective. However, the impacts were severe, highlighting the significant changes in climate experienced in recent years.
The study found that the likelihood of such a heatwave happening is now four times greater than it was in the year 2000. This stark comparison emphasizes the rapid acceleration of climate change, making the issue even more pressing. The analysis examined a large swath of the continent, including southern California, Arizona, New Mexico, Texas, Oklahoma, Mexico, Guatemala, El Salvador, Belize, and Honduras, focusing on the five consecutive days and hottest five consecutive nights. The attribution team used both current and past temperature measurements, comparing them to past heatwaves to determine the extent to which global warming factored into the 2024 heatwave.
The immediate meteorological cause was a high-pressure system parked over central North America, blocking cooling storms and clouds. This system then moved to the US Southwest and is now bringing the heat to the US East. While some respite may come in the form of Tropical Storm Alberto, which is heading towards northern Mexico and southern Texas, the heatwave has already had a devastating impact. Mexico and other regions have been struggling for months with drought, water shortages, and brutal heat. The heat has even caused trees to drop their leaves in Mexico, a testament to the extreme conditions.
The study highlights the exacerbating effect of the heatwave on existing inequalities between the rich and poor in the Americas. The lack of access to air conditioning and other cooling measures disproportionately affects vulnerable populations, making them more susceptible to the dangers of extreme heat. As the planet continues to warm, the frequency and intensity of these heatwaves will likely increase, demanding urgent action to mitigate the effects of climate change and protect vulnerable populations.
