Americans are more at risk than ever from the deadly effects of heat, according to a new study.

Researchers at the Journal of the American Medical Association estimate that between 1999 and 2023 there were 21,518 deaths in which heat was either the underlying or contributing cause of death. This may be an underestimate, they say. Overall, heat-related deaths have increased by 117% since 1999.

The authors of the study published on Monday used data from the Centers for Disease Control and Prevention to calculate death rates.

While the number of heat-related deaths has fluctuated from year to year, there has been a sharp increase over the past seven years. According to the data, heat-related deaths increased by 16.8% annually from 2016 to 2023 – and researchers expect the numbers to continue to rise.

“As temperatures continue to rise due to climate change, the recent upward trend is likely to continue,” the authors write.

Last year was not only the hottest year since weather records began but also the deadliest: A total of 2,325 people died from heat, the study found. From January to December 2023, around 120,000 people were admitted to the emergency room for heat-related illnesses, according to CDC data. Over 90% of these visits occurred in the peak summer months of May to September.

Rising temperatures due to climate change have led to record-breaking heatwaves across the country in recent years. According to the record of warmest July ever The National Oceanic and Atmospheric Administration said in a phone call this month that there is a 77% chance that 2024 will be the hottest year on record in 175 years.

The international community is also struggling with the deadly effects of the heat. A study recently published in Nature Medicine It is estimated that 47,000 people died from heat in Europe last year.

Experts believe that the number of heat-related deaths in the United States and worldwide is likely underestimated. This is due to the way heat-related deaths are recorded.

“People often come to the emergency room or hospital with a heart attack, stroke, asthma attack or kidney failure, and heat is often not noted as an underlying cause in medical records,” said Dr. Céline Gounder, medical editor at CBS News. CBS News said earlier this month.

As temperatures rise every year, states desperate efforts to take life-saving measuresThe authors of the Journal of the American Medical Association recommend that local governments invest in cooling centers, air conditioning and hydration stations to help people beat the heat.

Other ways to protect yourself from extreme heat, Dr. Gounder said, include taking advantage of state and federal tax credits for residential renewable energy projects and ensuring your home is adequately insulated.

On an individual basis, Dr. Gounder recommends cold showers and breaks in the shade when you are outdoors.