Extreme heat is the No. 1 weather-related cause of death in the United States, killing more people most years than hurricanes, floods and tornadoes combined. A new report shows that extreme heat will generate approximately $1 billion in health care costs in the U.S. every summer.
However, unlike other natural disasters, many people are uncertain about how to, or simply unable to, protect themselves from extreme heat — or don’t perceive heat as a personal threat.
Heat risks to human health are not prioritized at the policy level compared to other climate-change impacts like flooding or wildfires. As we swelter through the hottest summer in modern history, it’s clear that this needs to change.
The body adapts to extreme heat through sweating and evaporative cooling. Natural systems for thermoregulation can fail when the body experiences prolonged heat exposure, or high humidity levels interfere with evaporation. Excessive sweating can lead to dehydration and salt depletion, which reduces blood pressure and causes electrolyte imbalance.
Extreme heat can aggravate chronic conditions such as migraine, arthritis, asthma, kidney disease, hypertension, Type 2 diabetes and cardiovascular disease. It can also increase the chances of having a heart attack. Infants and toddlers, pregnant women, and the elderly are also disproportionately affected by extreme heat, as they have more difficulty regulating their body temperature. But even healthy individuals without any risk factors are vulnerable to adverse health outcomes from extreme heat exposure.
All levels of government and the private sector need to begin addressing the threat of extreme heat. A recent report by the Center for American Progress and Virginia Commonwealth University makes several recommendations to systematically address these challenges.
1. Reduce greenhouse gas emissions: A new analysis has confirmed that the recent heat waves in parts of China, Europe and North America topping 113 degrees would have been virtually impossible to reach absent the burning of fossil fuels and the emission of greenhouse gases. Unless decisive action is taken to address climate change by transitioning from fossil fuel use to clean, renewable energy sources, temperatures will continue to rise, and heat waves will become more common.
2. Improve data surveillance and risk communication: To effectively monitor and anticipate heat events and their impact on public health, communities must have access to better data and enhanced modeling techniques. Prior to and during heat emergencies, it is crucial for the public to receive accurate and timely information about the risks associated with extreme heat and the necessary precautions to prevent heat-related illnesses.
The Biden administration recently announced plans to spend $7 million to develop more detailed weather predictions to anticipate extreme weather like heat waves, but this needs consistent and sustained funding.
3. Increase community resilience to extreme heat: People in dense urban environments experience the most severe impacts of extreme heat. Urban centers tend to have a high density of buildings, paved roads and parking lots that absorb and retain heat. They also tend to have fewer green spaces like parks, which reduce heat levels in neighborhoods by lowering surface and air temperatures through evapotranspiration. They also have less mature trees and other natural features that provide shade, deflect the sun’s radiation and release moisture into the atmosphere. This is known as the “heat island” effect.
In cities such as New York, Detroit and Baltimore, central air-conditioning may not be an available or affordable solution. Many older buildings have never been retrofitted to accommodate central air, leaving people reliant on smaller, portable window units and fans that are less efficient and drive up electricity costs. A 2020 report found that low-income households in America spend 8.1 percent of their income on energy, compared with 2.3 percent for non-low-income households. The ability to reduce energy costs is largely out of the control of renters and may be unaffordable for lower-income homeowners.
According to the United Nations Population Division, 68 percent of the planet’s population will live in urban areas by 2050, up from 55 percent in 2018. We cannot afford to ignore the heat island effect in urban areas, and need to better integrate it into urban planning and residential building codes. We also need comprehensive local community action plans to deal with heat emergencies in real time.
4. Establish and strengthen governmental responsibilities for extreme heat protections: From 2011 to 2021, 436 workers died from heat exposure, according to the Bureau of Labor Statistics; this number is likely an undercount, as heat-related deaths are often attributed to other accidents or health conditions. Public officials should embrace a comprehensive, collaborative approach to addressing extreme heat and the broader challenges of climate change. This will enable coordinated efforts aimed at effectively mitigating the effect of extreme heat on communities. One example is Phoenix, Arizona’s publicly funded Office of Heat Response and Mitigation.
5. Strengthen health care services and early detection of heat-related illness: The public needs to be educated about the warning signs of heat-related illness and have access to appropriate care. Health care systems should also prioritize training providers on treatment protocols and reinforcing their infrastructure to ensure uninterrupted services during heat waves and power outages.
As temperatures continue to soar, we need to take extreme heat as seriously as other natural disasters. The cost to our health and economy is too steep to ignore.
Dr. William Haseltine is a former Harvard Medical School professor and founder of the university’s cancer and HIV/AIDS research departments. He serves as Chair and CEO of the think tank ACCESS Health International.