In a landmark piece of climate journalism, Reuters has just published a groundbreaking investigation arguing that the term “heat waves” no longer adequately captures what is happening on the planet. A better term is “heat storms,” wrote Maurice Tamman, a veteran investigative journalist who was the lead reporter on the “Age of Heat Storms” project.
“Supersized heatwaves used to be rare,” Tamman wrote. “No longer. Now they swarm the planet.” In a video accompanying the report, he explained that “whereas heat waves were once small and relatively self-contained, now we live in a world where these heat waves are massive.”
Drawing on interviews with dozens of scientists and researchers, Reuters defined a “heat storm” as an episode of “abnormally high temperatures” that lasts for at least five consecutive days and covers more than 1 percent of the earth’s surface, an area roughly the size of half of Canada. Whereas the planet averaged about five heat storms per year in the 1960s, the largest of which covered 6 percent of the planet and lasted for 46 days, the average today is 102 heat storms per year, the largest of which affected 85 percent of earth’s surface “and virtually every single human being living in 2023 and 2024.”
Heat storms, Tamman added in the video, are not only larger and stronger than heat waves, they “are also different in another way: They are cascading, where there is an endless series of storms, one after the other.” Indeed, for the last 18 years straight, “at least one heat storm has been roiling the planet, and often more than one,” according to a fresh analysis of global temperature data that Reuters conducted with the scientists.
Tamman, who won a Pulitzer Prize in 2025 for an exposé on the global fentanyl trade and has covered climate change for years, was drawn to this project after having long been “frustrated by a disconnect between scientists and the public,” he wrote. It can be useful for scientists and policymakers to talk about the need to limit global warming to two degrees Celsius (3.6 degrees Fahrenheit) above preindustrial levels, he acknowledged, but “what is an ordinary person to make of that? Not much.” Extreme heat, on the other hand, is something that ordinary people viscerally understand—and that nearly everyone on earth has now experienced. In recent months, global warming and the heat that follows has become even more visceral, bringing ever more extreme events like last summer’s glacier collapse in Nepal and the deaths of more than 35,000 people across Europe.
Like the best climate reporting, the Reuters investigation both humanized and localized the story. One installment told the story of Justice Trumpler, a 17-year-old high school football captain in Texas who invites college recruiters to watch him play, only to succumb to nonstop vomiting in the 100-degree heat and end up in the hospital. Another installment described how hundreds of the iconic pink dolphins that inhabit the Amazon river were literally cooked to death by extreme heat. In the Philippines, a math teacher saw a student face down on his desk, crying; when the teacher coaxed him to sit up, the boy’s face and chest were covered in blood from a spontaneous nosebleed, a common malady in extreme heat.
All this and more is happening, bear in mind, after average global temperatures have risen by “only” 1.4 C. And because emissions continue to increase, temperatures are projected to rise to at least 1.7 C by roughly 2050, the United Nations Environment Programme said in its annual “Emissions Gap” report, released October 13. A key reason emissions keep increasing, The New York Times reported, is that the U.S. under President Donald Trump has reversed its previous efforts to limit fossil fuel production. To limit the amount of “overshoot” of the Paris Agreement goal of 1.5 C of temperature rise, UNEP said, “a massive global scale-up” in emissions reductions will be needed, a goal certain to be discussed at the COP31 U.N. climate summit taking place in Turkey from November 9 to 20.
To help both the public and policymakers grasp how harshly even today’s 1.4 C of global warming is transforming life on earth, the Reuters project suggested that heat storms be given names, just as hurricanes routinely are. According to the report, “Naming events is ‘a powerful way for people to understand that something is happening,’ Anthony Leiserowitz, director of the Yale Program on Climate Change Communication, told Reuters. Yet ‘we don’t currently do that with heatwaves,’ he said, even though heat has been estimated to kill almost half a million people a year.”
In online discussions, some meteorologists have bristled at the term “heat storm.” David Dickson, Covering Climate Now’s resident meteorologist, noted that “storm” is a term “with a very distinct meteorological definition that is the opposite of what happens during extreme heat (storms occur with low pressure, heat with high pressure).” However, Dickson added, “I can’t think of a better name, and think it does the job in communicating impacts quite well—and we already have other things described as storms that aren’t, i.e., solar storms.”
For nearly a decade, thousands of climate scientists have been deliberately using the term “emergency” to describe how fast and dangerously global warming is intensifying. Activists picked up the “emergency” framing as well, but the Reuters findings underscore that that framing has always been fundamentally a matter of science, not politics.