Thousands of migrants—many of whom are children—are suffering from deadly heat at the U.S.-Mexico border. As the effects of climate change worsen day by day, extreme weather conditions are putting migrants attempting to enter the United States through the Sonoran Desert at high risk of dehydration and death.

To identify the deadliest areas along the U.S.-Mexico border, scientists and researchers used a biophysical model of human dehydration. According to the report generated by this model, it was found that most of the deaths were primarily caused by severe dehydration. After organizing the dataset by region based on the number of casualties, the report established a link between severe dehydration leading to death, water loss, organ failure, disorientation, and physiological challenges in animal species.

“We provide the first empirical evidence that the physiological stresses experienced by humans attempting to cross the Sonoran Desert into the U.S. are sufficient to cause severe dehydration and associated conditions that can lead to death. A disproportionately large percentage of migrant deaths occur in areas where the predicted rates of water loss are highest,” says Ryan Long, an associate professor of wildlife sciences at the University of Idaho. Long also emphasizes the importance of access to drinking water supplies for mitigating risks during migration across the region’s borders, particularly in areas with the highest rates of water loss.

Models developed to address climate change and water scarcity unfortunately show that these types of border crossings will only become more dangerous over time, increasing the already high number of people who do not make it across. Immediate action must be taken to mitigate this crisis.