A new study indicates that rising temperatures are leading to more heat-related fatalities in the U.S., based on federal data from 1999 onward.

According to findings released on Monday, 2023 saw the highest number of heat-related deaths recorded in over twenty years. Last year also marked the hottest year globally, underscoring the troubling trend linked to climate change.

The research, published in the JAMA journal of the American Medical Association, revealed that 2,325 individuals died from heat exposure in 2023. Researchers believe this number is likely an underrepresentation. Adjustments were made for population growth and aging, yet the death rates remained alarmingly high.

“The current path we’re on regarding warming and climate change is beginning to manifest in rising death rates,” stated Jeffrey Howard, the study’s lead author and an associate professor of public health at the University of Texas at San Antonio, in an interview with YSL News. “This is something we had not quantified before.”

Howard collaborated with researchers from the Uniformed Services University of the Health Sciences in Maryland and Pennsylvania State University to analyze death certificate records from 1999 to 2023. Deaths were counted if heat was indicated as a primary or contributing cause.

The number of reported heat-related deaths remained stable until around 2016, after which there was a noticeable increase, which Howard describes as a “hockey stick” pattern. This term also applies to the alarming rise in global temperatures linked to climate change.

The study indicates that the rate of heat-related deaths, adjusted for population size and age, has climbed significantly since the early 2000s across all demographics.

Notably, the recent trend has escalated sharply. In 2022, there were 1,722 deaths with an adjusted rate of 0.47 per 100,000, but in 2023, the adjusted rate rose to 0.63, with 603 additional deaths—marking the highest rate recorded.

Deaths were not evenly distributed across the nation. According to Howard, most fatalities occurred in regions typically associated with high heat, including Arizona, California, Nevada, and Texas.

The study has limitations regarding how local governments categorize heat-related deaths, potentially leading to underreporting. Additionally, as awareness of heat dangers grows, the data might not capture all vulnerable populations. Those at higher risk include individuals without air conditioning, outdoor workers, and those with existing health conditions.

Heat is often referred to as a silent killer, according to Sameed Khatana, an assistant professor of medicine at the University of Pennsylvania and a cardiologist at the Philadelphia VA Medical Center who has researched heat death statistics.

Khatana noted that authorities are increasingly aware of the importance of accurately completing death certificates regarding heat exposure. “There is a growing understanding of these nuances that have been highlighted in research over recent decades,” he added.

Experts like Khatana have previously advocated for better reporting practices for heat-related deaths.

Counties across the U.S. have varying methods for attributing heat-related fatalities, according to Ashley Ward, director of the Heat Policy Innovation Hub at Duke University’s Nicholas Institute for Energy, Environment and Sustainability. “There is a need for clear guidance and standards on how to classify heat as a contributing factor,” she explained.

Researchers involved in the study released on Monday urged local authorities to prioritize investments in hydration stations, public cooling centers, and more buildings with air conditioning.

This summer of 2024 has continued to see extreme heat conditions. While it’s unclear how this year’s death toll compares, several heat waves have swept the nation recently.

In Phoenix, for instance, a new record has been set for consecutive days exceeding 100 degrees, with Mark O’Malley, a meteorologist at the National Weather Service office in Phoenix, stating Sunday marked the 91st straight day of such temperatures recorded at Sky Harbor Airport.

July also broke records for the hottest month in California and New Hampshire, with 19 other states reporting one of their top 10 warmest Julys, as noted by the National Oceanic and Atmospheric Administration.

On a global scale, three consecutive days in late July were the hottest ever recorded, breaking previous July highs. The NOAA estimates a 77% chance that this year will be the hottest on record.

“Overall,” Howard concluded, “it appears that conditions are worsening instead of improving.”