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Investigating climate change and the military heat crisis Date: 11/18/19

By David Hasemyer

Case No. 20160614001 was among the decade’s worth of data the military had gathered that showed a steady increase in the number of military personnel harmed by heat.

The story behind case No. 20160614001 was that of Sgt. Sylvester Cline, an Iraq veteran and father of five who collapsed and later died after enduring hours under a scorching sun during a field exercise at Fort Chaffee in Arkansas.

The death of Sgt. Cline became the lead for my InsideClimate News/NBC investigative story showing more U.S. troops are falling to heatstroke and heat exhaustion as the military struggles to balance training with rising temperatures.

Heat-related illnesses pose a significant threat to the health and operational effectiveness of military personnel in the United States. Soldiers are dying of heat stroke and thousands are falling ill every year.

Heat has become such an urgent issue that the Defense Health Agency issues an annual report that tracks the number of heat-illnesses in the military and identifies the bases where heat takes its greatest toll.

A 2019 report by the agency shows heat-related illnesses have been steadily increasing since 2014 across all branches of the service. That year, there were 1,751 heat illness – heat stroke and heat exhaustion – reported. In 2018, there were 2,792 heat illness reported.

During the same five-year period, 11,452 heat-related illnesses were diagnosed at more than 250 military installations and geographic locations worldwide with installations in the U.S. accounting for 95 percent of the illnesses. 

“Although numerous effective countermeasures are available, heat- related illness remains a significant threat to the health and operational effectiveness of military members and their units and accounts for considerable morbidity, particularly during recruit training in the U.S. military,” according to the study.

The report lists the top 19 bases for heat illness, but the health agency’s public affairs people can assist with a more detailed breakdown of every base reporting a heat-related illness. 

How do you tackle a story like this for your part of the country?

You can review heat casualties at individual bases across the country. Take Fort Hood in Texas, for example, where 272 heat illnesses were reported between 2014 and 2018.

In the case of Fort Hood, the heath agency would be queried for the back-up information on each of those 272 incidents. The agency will not release names, and may release only the limited statistical information provided by the base. But ask for the date of each incident and any case number specific to investigations conducted at Fort Hood.

That information then leads to Fort Hood where requests can be made for information on each of the incidents. The base public affairs people probably will have bare-bones news releases on a few of the incidents. The dates also provide a starting point for a Nexis search for any news coverage of the incidents.

But it’s most likely that a Freedom of Information Act request will need to be made for the detailed investigative reports. When a death is involved, often times local medical examiners have a case.

For a breakdown of information in the Defense Health Agency report, contact

Military Health System Communications

A deeper dive into heat illness was done through analysis of data supplied by the safety centers of the various military branches. Information teased from that data included the estimated costs associated with heat-related deaths and illness, the length of hospital stays and how long the illness kept personnel out of duty. 

A minimum story could be based on the Defense Health Agency data to identify and locate bases. The maximum story could be based on analysis of the data supplied by the various Combat Readiness Centers and through material obtained via FOIA.

The story of Sgt. Cline, Case No. 20160614001, was developed from data supplied by the Army’s Combat Readiness Center. (also at
The Combat Readiness Center’s PIO is Michael J. Negard. 

The other safety centers that provided data:

The Air Force Safety Center
Joshua Acock, Air Force Safety Center PIO 
505 846 2098

The Navy/Marine Corps Safety Center
April Phillips, Navy Safety Center PIO
Norfolk, Va.

Drilling down on specific cases required filing FOIAs with the resulting delays caused by processing the requests that ranged from six weeks to six months. Be specific when filing FOIAs seeking reports associated with the military’s investigations into heat cases. 

A recent study by the Union of Concerned Scientists shows military personnel at bases across the country could face an extra month of life-threatening heat every year by mid-century. The analysis features an interactive map that highlights the potential increase in heat at 169 bases in the United States.

How does heat kill and devastate the armed forces?

Heat exhaustion is the most common heat illness in the military. It’s caused by the inability of the heart to pump strongly enough because of strenuous physical exertion, ambient heat and dehydration. Heat exhaustion is diagnosed when the core body temperature is between 100.5 degrees and less than 104 degrees. It’s usually overcome with rest and cooling that includes removing unnecessary clothing, relocation to a cooler environment, and drinking cool fluids.

The most dangerous heat illness is heatstroke. It is characterized by a core body temperature of 104 degrees or greater. It can produce central nervous system dysfunction such as delirium, seizures, coma, and organ and tissue damage. The onset of heat stroke requires aggressive clinical treatments, including rapid cooling and supportive therapies such as fluid resuscitation to stabilize organ function.

Although rare, heat can also lead to hyponatremia, a condition that occurs when soldiers drink too much. This causes an imbalance to the body chemistry that can lead to debilitating convulsions and even death.

At Fort Chaffee, heat stroke incapacitated Sgt. Cline after a few hours in the sweltering sun and humidity under the weight of heavy gear and the exertion of war games. Cline became exhausted. His head throbbed with a blinding headache. He was twisted by back spasm and his extremities went numb. His legs cramped so badly he needed assistance walking. He began to vomit and breathing slowed and then stopped.

It quickly became a full blown emergency to save Cline’s life. Medical personnel started CPR and forced air into his lungs using a respirator mask and bag. He was injected with epinephrine and atropine to offset cardiac arrest. Defibrillator pads were applied in case his heart needed a shock. A helicopter was ultimately ordered to evacuate to a hospital. But it was too late. Emergency room doctors pronounced him dead. The heat had killed him.

Global warming forms the backdrop for the military heat crisis.

Climate change – with heat as its most harsh element – “will have wide-ranging implications for U.S. national security interests over the foreseeable future,” according to a 2015 Department of Defense report. Heat becomes a threat multiplier – a peril called out in another DOD report published in 2014 - because it has the potential to exacerbate many of the challenges the military is already facing in some of the world’s most destabilized regions. 

Heat has been responsible for more deaths in the United States over the past 30 years than any other natural hazard – more than floods, hurricanes, or tornadoes. Climate change is making the heat worse.

Average annual temperatures are now about 1.8 degrees Fahrenheit higher than they were over the period 1895-2016, and the past three years have been the warmest years on record for the globe, according to the Fourth National Climate Assessment. 

If greenhouse gas emissions continue on the current path, global average temperatures could rise 8.5 degrees Fahrenheit by the end of the century, the assessment found. The resulting extreme heat could lead to tens of thousands of premature deaths every year across the United States.

Combating heat illness is taking on urgency with the military. Specialized medical units are being established to develop new preventive measures to mitigate heat stress. Guidelines for assessing heat risks are being revised, and treatment protocols refined.

The Army’s Research Institute of Environmental Medicine has teamed with doctors at Ft. Benning’s Heat Center to launch a study of soldiers engaged in intense physical training in the heat and humidity.

Institute doctors and engineers wanted to identify the threshold at which the body begins to succumb to heat, a project the Army hopes will ultimately lead to the most definitive policies designed to reduce heat illnesses ever published.

They are developing a device to monitor recorded soldiers’ heart rate, and skin and core body temperatures while they train. 

For information on the monitor and other medical issues involving heat, contact Mallory Roussel, Research Institute of Environmental Medicine PIO at 508-233-5601 or

The device is being tested at Fort Benning in conjunction with the base Heat Center. The center at the Martin Army Community Hospital seeks to improve and regiment the approach to handling heat illnesses beginning with leaders and medics in the field; at the hospital, and with follow-up medical care; and by better prevention protocols and research into the factors contributing to heat illness.

Connect with Terry Beckwith, hospital/heat center PIO

The military’s research and development arms are working on lighter weight uniforms, cooling vests and personal heat monitors. Its medical people are focused on studying heat stress and the effectiveness of the new uniforms and equipment.

The Natick Solider Research Development and Engineering Center is the Army’s research and development agency.
Debra Dawson (She goes by Debi.)

Jeff Sisto

David Hasemyer has been a reporter for InsideClimate News since 2013. He is co-author of the “Dilbit Disaster: Inside the Biggest Oil Spill You've Never Heard Of,” which won the 2013 Pulitzer Prize for National Reporting, and co-authored the 2016 Pulitzer Prize finalist series “Exxon: The Road Not Taken.” Prior to joining ICN, Hasemyer had an award-wining career at The San Diego Union-Tribune as an investigative reporter. Hasemyer's work has been recognized by the Associated Press, the Society for Professional Journalists, the Society of American Business Editors and Writers. He also has been a finalist for the Gerald Loeb Award and the Robert F. Kennedy Award for Social Justice and Human Rights.