Monday, April 15, 2024


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The Grand Canyon’s High Temperatures Could Pose an Increased Risk

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Each year, countless individuals travel to U.S. national parks. They engage in hiking activities at Yosemite, witness geysers erupting at Yellowstone, and appreciate the famous views of the Grand Canyon. However, the number of park visitors experiencing heat-related health concerns is increasing.

According to a recent research, experts predict that the prevalence of heat-induced illnesses in visitors to Grand Canyon National Park could increase by over two times in the future due to the ongoing effects of climate change.

This research offers a practical demonstration of the dangers that arise from climate change for the well-being of the general population.

Jennifer Marlon, a researcher at Yale School of the Environment and the Yale Program on Climate Change Communication, who was not part of the study, stated that the study serves as a valuable demonstration of the dangers that climate change presents to public health.

In 2022, over 4.7 million individuals visited the Grand Canyon, making it one of the top national parks in the United States. While many enjoy hiking or taking in the breathtaking scenery, hot weather can pose a risk for heat-related illnesses when spending time outdoors and engaging in physical activity.

Elevated temperatures may lead to overheating in individuals. This may result in mild symptoms such as temporary cramps, nausea, or fatigue. However, in severe situations, these symptoms can become life-threatening. Pregnant individuals, the elderly, and those with preexisting heart or respiratory issues are at a particularly high risk for serious illness.

In the southwest region of the United States, there is a growing number of heat waves and droughts caused by climate change. These events are expected to become more severe in the future. According to Marlon, there has been an increase in the frequency and duration of heat waves, which used to only happen for about two weeks during the summer but now occur for more than two months each summer.

As the region is home to many of the country’s top national parks, a large number of individuals will engage in outdoor activities in areas that are predicted to experience increasingly hot and dry weather. These conditions could potentially lead to areas of intense heat, increasing the risk of heat-related illnesses.

The importance of temperature and humidity is significant, but timing also plays a crucial role.

In the recent research, scientists estimated the potential impact of climate change on the likelihood of heat-related sickness in Grand Canyon National Park. They analyzed information on park attendance, incidents of heat-related illness, as well as temperature and humidity levels from 2004 to 2009 in order to establish a starting point for risk assessment. Within this timeframe, there were a total of 483 cases of heat-related illness, resulting in six fatalities, according to records from the National Park Service.

The scientists utilized 14 different climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5) to predict changes in temperature and humidity during the peak visitation season for each year until the end of the century. They considered two potential scenarios: one where greenhouse gas emissions reach their highest point in 2040 and then decline, and another where emissions continue to increase. Based on this, they calculated the potential increase in heat-related illnesses under each scenario.

Based on the findings, there could be a 29% to 137% rise in the number of cases by 2100. However, this prediction does not take into account the expected increase in annual visitors to the park. Taking into account recent visitor numbers, the most severe model predicts over 250 cases of heat-related illness per year by the end of the century, compared to the average of 81 cases annually from 2004 to 2009.

The scientists discovered that the timing, not just the temperature, is crucial. While July and August are the hottest months at Grand Canyon National Park, the data indicated that the likelihood of heat-induced illnesses is greatest in the “shoulder season” of April and May, when visitors may not be adequately prepared for high temperatures.

According to Marlon, a significant number of individuals visiting national parks are not adequately equipped for the physical demands and heightened exposure to natural elements. As global warming leads to more frequent heat waves during off-peak seasons, hikers who are unprepared for high temperatures will face greater danger.

Fighting the Heat

The recent research could inform strategies for boosting patrols in the off-season.

The NPS has implemented strategies at the Grand Canyon to supervise and address heat-related sickness, such as proactively conducting search and rescue patrols during the busiest time of year. According to Danielle Buttke, an epidemiologist and health coordinator for the NPS and primary author of the research, this recent study could inform decisions to intensify patrols during less busy times. Additionally, the expected rise in heat-related illness may assist the NPS in preparing for the future by constructing additional shade structures and water stations along popular trails.

Ensuring that visitors are prepared is essential in preventing heat-related sickness. However, in order to be prepared, visitors must first understand the dangers of extreme heat. According to Larry Perez, the communications coordinator for the NPS’s Climate Change Response Program, effectively communicating with various audiences is a crucial step in addressing this issue. The study’s findings indicate that informing visitors about extreme heat during the shoulder season, when temperatures are usually cooler, could help reduce the increasing risk caused by climate change.

The National Park Service (NPS) reaches out to educate visitors about the dangers of heat and the possible impacts on their health. To avoid heat-related illnesses, park visitors should stay hydrated, limit their time outside, and pay attention to their body’s reactions to heat. If they experience symptoms recommended by the U.S. Centers for Disease Control and Prevention (CDC), they should find shade and take a break. If the symptoms continue or worsen, it is advised to seek medical assistance, as recommended by the CDC.

—Caroline Hasler (@carbonbasedcary), Science Writer

This article is part of our ENGAGE resource, which provides science news for teachers to use in their classroom instruction. Take a look at all the ENGAGE articles and let other educators know how you incorporated this article into a lesson by leaving a comment below.

Hasler (2023) states that the extreme heat at the Grand Canyon could potentially pose a greater threat in the future. This information was published in Eos on September 15, 2023, and can be accessed at

Text © 2023. The authors. CC BY-NC-ND 3.0

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