2023 Declared Hottest Year in Recorded History: Impact on Military Heat Risk and Illness
The World Meteorological Organization has recently declared that 2023 was the hottest year in recorded history. This announcement comes as no surprise to Lisa Polyak, an environmental engineer at Defense Health Agency Public Health, who has been closely monitoring heat data and reporting the results annually for the U.S. Army’s Health of the Force report. The report, published by Defense Centers for Public Health – Aberdeen, highlights the increasing heat risks faced by Army bases worldwide.
Polyak notes that the trends indicate that 2023 being the hottest year is not an outlier. The 5-year average of annual heat risk days exceeded the 15-year average at 84% of the 44 bases tracked, showing a steady increase in heat risk as we move forward. Heat risk hours are counted when the National Weather Service heat index is above 90 degrees Fahrenheit, and many locations in the U.S. experience 25 or more heat risk days during the summer months.
In July 2023, 720 service members were diagnosed with heat illness, with the U.S. Army and Marines having the highest burden and rate of heat illness among the services. The Wet Bulb Globe Temperature index is used to measure heat stress in military training settings, taking into account temperature, humidity, wind speed, sun angle, and cloud cover. It is essential for leaders to monitor not only ambient heat but also mission-related and individual risk factors when assessing heat risk.
The 2023 Heat Illness Report to Congress revealed that 84% of heat illness cases occurred on days that did not experience black flag conditions, indicating a need for better heat illness prevention measures in moderate conditions. Seven U.S. Army training installations experienced a significant number of heat risk hours in July and August 2023, highlighting the need for intervention and prioritization of locations facing the worst conditions.
Military leaders can take various steps to prevent heat illness, such as providing resources on hydration strategies, proper cooling techniques, acclimatization to heat, and risk mitigation strategies. Monitoring heat risk and implementing adaptive measures like ‘reverse-cycle’ training or shifting training away from summer months may be necessary in the future. It is crucial to consider motivation in preventing heat illness, as excess motivation in hot conditions can increase the risk.
Overall, resources are available to help military leaders and service members reduce exertional heat illness. The Defense Health Agency is committed to improving health and building readiness, ensuring exceptional outcomes in the face of increasing heat risks.