More Illness, Greater Cost Spotlight Brief: Heat Emergencies 

Published with the Common Health Coalition and conducted by researchers at the Johns Hopkins Bloomberg School of Public Health

Executive Summary

Building upon the Common Health Coalition’s series of “More Illness, Greater Cost” reports, this Spotlight Brief demonstrates the health and economic impacts of heat emergencies, using a summer heat wave as a case study. A modeling analysis conducted by the Johns Hopkins Bloomberg School of Public Health finds that:

• State Impact: Under a scenario representing today’s levels of public health preparedness, a significant heat wave – a period of unusually hot weather lasting five days – in one state could cause 300 deaths and 4,000 heat-related emergency department (ED) visits and preventable hospitalizations. Those impacts may generate approximately $870 million in total costs, including $48 million in medical costs, $810 million in disrupted livelihoods, lost wages, and diminished well-being and $19 million in other social costs. If two large outdoor events took place during the heat wave, those impacts could be even greater – reaching approximately $920 million in total costs.
  
• National Impact: Given that the United States Environmental Protection Agency (EPA) estimates that the U.S. can expect roughly six heat waves each year across its largest metropolitan areas, findings from the modeling analysis suggest total costs for these heat waves could approach more than $5 billion annually nationwide.

Extreme heat, which is becoming increasingly common, is already the deadliest weather event in the United States, responsible for more deaths each year than hurricanes, floods, and tornadoes combined. At the same time, federal and state policy changes are eroding public health preparedness staffing and programs. When public health infrastructure is weakened, the consequences are more likely to be felt downstream. The greatest financial damage is an invisible tax on daily life, borne by parents forced to miss work, hourly employees losing vital income, and local employers facing sudden operational paralysis. Hospitals and health systems face financial and operational strain from surges in emergency department visits and hospitalizations, payers absorb increased health care expenditures, and public health agencies deploy emergency resources to mitigate harm to affected communities. 

But these impacts are not inevitable. Past emergencies have shown that investments in preparedness and response capabilities can be both life-saving and cost-saving. Investments that yield reductions in adverse health outcomes by 10-30% during a heat event have the potential to save a state an estimated $210 million in overall costs, according to the model.

Achieving meaningful reductions in deaths, hospitalizations, and other preventable harms requires coordinated action across public health, health care, employers, payers, and policymakers. This brief outlines the evidence and actionable steps to reduce the impacts of extreme heat, from immediate interventions that blunt the effects of heat waves (e.g., cancelling large spectator events) to long-term structural investments that address upstream risk factors and strengthen resilience.