Extreme Heat Continues to Alter Our Planet

Extreme heat has prompted countless warnings across the United States and Europe this past week. With climate change, heat waves will become more severe, frequent, and last longer, resulting in more substantial public health impacts. 

Monthly global temperature. Source: National Center for Environmental Information.

Residents throughout much of the Central and Western United States experienced unsafe levels of heat this past Monday, July 18. Almost 56 million people, 17% of the population of the Lower 48 States, live in areas with dangerous levels of heat. Regions of Kansas, Oklahoma, and Texas reached temperatures as high as 110 degrees. Austin, Texas just recorded its hottest seven-day period in history. Tulsa, Oklahoma averages 10 triple-digit days a year and just experienced its 11th triple-digit day last week. Parts of the Southwest as well as Southern California are also experiencing record-breaking heat levels. South Central California, including The San Joaquin Valley, recorded temperatures ranging from 102 to 107oF.  

Across the pond, regions of Western Europe are simultaneously experiencing unprecedented heat levels. Many monthly and all-time temperature records have not only been broken, but completely shattered. The United Kingdom experienced its third hottest day on record and its hottest day of the year on Monday and recorded its highest temperature ever (104oF) on Tuesday.  

Italy is experiencing dual threats: extreme heat and drought. There, drought has curbed agricultural output and caused two hydro-electrical plants to close from lack of water to cool them. In Madrid, Spain, residents experienced their fifth night in a row during which temperatures did not go below 77oF.  

This extreme heat has resulted in widespread wildfires across parts of Spain, France, and Portugal. Wildfires have burned over 35,000 acres in France and have caused the evacuation of at least 28,000 people. In Portugal, wildfires are running rampant through the country’s central and northern regions, causing over 421 heat-related fatalities between July 14 and July 17. The number of deaths caused by exposure to heat will likely be larger than what is currently being reported. 

Incessant heat is a major public health threat resulting in a range of impacts to the body. Heat-related illnesses occur when the body is incapable of cooling down or when an individual’s core body temperature exceeds 106oF. Sweating is a cooling mechanism used to remove heat from the body, but when the air is humid, sweat cannot evaporate and cool the body down, leaving individuals vulnerable to heat exhaustion. Heat exhaustion, which can include symptoms such as headaches, fast breathing or pulse, excessive sweating, and dizziness and confusion, can progress to heatstroke, which can be deadly. Extreme heat events can also exacerbate many chronic conditions, including cardiovascular disease and respiratory disease.  

While anthropogenic climate change affects the extent and severity of heat waves, a variety of other factors contribute to an individual’s risk for acquiring a heat-related illness. The social determinants of health, including income and education levels, are significant influencers. For example, neighborhoods with hotter temperatures and less energy-efficient housing tend to be in redlined communities and contain mostly communities of color. Older adults and individuals with pre-existing conditions are also particularly vulnerable to heat-related health impacts. The ability to regulate one’s bodily temperature typically declines with age, and many adults also take medications, such as those for epilepsy and Parkinson’s disease, that hinder the body’s ability to regulate temperature.  

Agricultural workers are also at an elevated risk of adverse health outcomes resulting from heat stress. Hotter temperatures resulting from climate change combined with lack of autonomy and workplace protections, payment for productivity practices, and lower socioeconomic status add to the likelihood of these workers acquiring a heat-related illness.  

Some countries are less prepared than others to cope with a warming global climate. Unlike the United States, air conditioning is not ubiquitous across Europe. In The United Kingdom, many houses have brick walls that absorb heat during the day and hold on to it at night. Furthermore, high energy prices resulting from the war in Ukraine have made many residents that do have air conditioning hesitant to use it, leaving people more vulnerable to heat-related illnesses. 

At the federal level, the Occupational Health and Safety Administration (OSHA) has already established new guidance for agricultural workers who are forced to work in extremely hot conditions. Additionally, many local health departments are developing extreme heat plans that target at-risk communities in their area. But as heat waves become more frequent and intense, public health officials need to continue to expand current prevention efforts. Building awareness is part of that effort, and greater public outreach is necessary to inform communities about the health risks of heat. 

The Los Angeles County Department of Public Health has partnered with the Los Angeles Regional Collaborative for Climate Action and Sustainability to create a social media campaign designed to reach people most at risk for heat-related illnesses. At the individual level, people should familiarize themselves with some of the most important ways to avoid dangerous overheating, such as drinking plenty of water, consuming electrolytes, and staying out of the sun. Even simple actions like adding ice cubes to a water bottle, covering home windows with a dark cloth to keep the sun out, taking a cold shower, and spritzing skin with cool water can help cool down the body.