
Governments and nonprofits are stepping up their efforts to provide tools and resources for both calculating and making the public aware of the risks of extreme heat.
Heat stress is the No. 1 weather-related cause of death, according to the World Health Organization — killing more people in the U.S. most years than hurricanes, floods, and tornadoes combined. But compared to flooding and storm surges from hurricanes or the danger from wildfires, the health risks from extreme heat are not nearly as well understood.
That’s partly because extreme heat lacks obvious physical markers — like excessive rainfall or smoke — that signal danger. “When a hurricane hits or a wildfire comes through, there’s no doubt about what just happened, but heat is more difficult because we don’t have those same context clues in our environment until it gets so extreme,” Ashley Ward, director of the Heat Policy Innovation Hub at Duke University’s Nicholas Institute for Energy, Environment & Sustainability, told NBC News’ Denise Chow earlier this year.
Heat-related risks also are complicated to assess, because multiple factors in addition to outdoor temperature play a role in the threat heat poses, including humidity, wind, and cloud cover. And due to such factors as tree cover and areas covered by concrete, temperatures can range widely within just a few city blocks.
For event planners, calculating and communicating heat risks to their meeting attendees will increasingly factor into their risk management plans: In 2023, which was the planet’s hottest year on record, the number of deaths related to excessive heat were the highest recorded in 45 years, according to an analysis by Associated Press. August 2024 was the Earth’s hottest August since the National Oceanic and Atmospheric Administration began keeping records 175 years ago.
As temperatures rise, governments and nonprofits around the globe have stepped up their efforts to provide tools and resources for both calculating and making the public aware of the risks of extreme heat, many of which can be useful for communicating the risks to meeting attendees, before and during events.
Among them are:
Chief Heat Officers: In 2020, the city of Miami hired a chief heat officer, the first position of its kind in the world, and at last count, nine more municipal and state governments around the world have followed suit, including Los Angeles, Phoenix, Athens, Melbourne, and the state of Arizona. Their primary role is to work with other agencies to create and implement long-range plans to help cities and states adapt to rising temperature, but their departments also work to raise awareness of the risks of extreme heat, according to the Climate Resilience Center, which piloted the world’s first chief heat officer positions. Many of their websites are linked to numerous local fact sheets and other resources.
Named heat waves: In July 2022, Seville, Spain, became the first city to name a heat wave — Heatwave Zoe — using a system to forecast and classify heat into categories ranging from “no risk” to “very high risk.” When a heat wave rises to the top category, it receives an official name to signify the elevated health risks, according to the Climate Resilience Center. A heat-wave ranking program launched in 2021 in Athens, Greece, has now expanded to six cities in that country and in California, the state Environmental Protection Agency is developing a heat-wave ranking system that is expected to launch in 2025.
Naming heat waves has both supporters and detractors, but a study published in Nature last April, which looked at how the name “Heatwave Zoe” affected how people behaved in 2022, found that people who remembered the name had been more likely to take protective measures against extreme heat.
A new U.S. heat risk index: The U.S. National Weather Service and the Centers for Disease Control and Prevention have developed a new index, now in an experimental phase, designed to make it easier for decision makers to calculate the risk that heat poses to the general population. The NWS HeatRisk index, which is searchable by ZIP code, combines multiple factors that contribute to heat stress to gauge the risk of heat-related health impacts, and provides heat-protection recommendations.
Barbara Palmer is deputy editor of Convene.