The already perilous desert crossing from Mexico to the US will become more dangerous as the climate warms, new research says. The research, published in Science, finds that dehydration is already a leading driver of mortality in people crossing on foot from Nogales in Mexico to Three Points in Arizona. It explains how extreme heat and water scarcity have claimed the lives of thousands attempting to enter the US from Mexico and quotes undocumented migrants, who confirm that dehydration, disorientation and organ failure are “common elements” of the journey. To-referenced record of adult male and female deaths recorded over 1981-2019 – focusing on May-September, when the weather is the hottest and driest and the most migrant deaths occur. The authors go on to show that as the climate warms, water loss will become even more extreme. They conclude that in 30 years, even under an “intermediate mitigation” scenario, people would be expected to lose one-third more water on a journey across the US southern border than they would today. One expert, who was not involved in the study, tells Carbon Brief that the paper makes for “bleak” and “tragic” reading – but that it is “important” work. However, he emphasizes that political decisions also play a part adding: “Those specific locations of the desert are dangerous and that is determined by the weather and climate. But the reasons people are in those specific locations are the result of myriad political decisions.” The desert crossing......The US has been the main destination for migrants since 1970 and is currently home to an estimated 40 million people who were born abroad. However, migrating to the US through legal channels is a complex and expensive process, which can take years or even decades to complete, and completely bars many people from entering the country. As such, hundreds of thousands of people enter the US every year without official documentation – many travelling on foot from Mexico. However, this journey is dangerous. Over 1998-2015, more than 5,500 people died attempting to cross the US–Mexico border – the majority in the Arizona desert. This study focuses on a portion of the Tucson Sector, a US Border Patrol jurisdiction that runs from Yuma, Arizona, to the New Mexico border. According to the paper, the region “has been a primary crossing point for migrants for nearly two decades” and “is characterised by the highest number of known border-crossing fatalities”.       https://www.carbonbrief.org/global-warming-will-make-undocumented-migration-into-us-increasingly-dangerous