The drying up of Rio Grande, United States

Problems

• The Rio Grande ranks as the fourth longest river in the United States, the fifth longest in North America, and the twentieth longest in the world at 1,885 miles. This truly massive body of water begins atop the snowy San Juan mountain range of the Colorado Rockies, flows down through New Mexico, and traverses the southern edge of Texas before ultimately emptying into the Gulf of Mexico (Dillworth). However, the river has been drying up in recent years. 

• Loss of snow pack and global warming

  
  According to NASA Earth Observatory, a 5-mile stretch of the Rio Grande near Albuquerque, New Mexico, ran dry for the first time in 40 years in July 2022. Farther downstream, more sections of the river had also dried up. Despite the wettest winter in a decade, this raised hopes for a better water year.
  
  Two primary factors are responsible for the remarkable drying of the West. Firstly, the loss of snowpack, which has historically acted as a natural reservoir, storing and gradually releasing water supplies for the region during the spring and summer. The drought has significantly reduced snow and rainfall over the past two decades.
  
  The second dynamic is global warming. Recent changes are a megadrought and perhaps permanent aridification because the Earth’s temperatures are steadily increasing, especially in the U.S. Southwest. Warming leads to more precipitation falling as rain than snow, which means far less precipitation is stored in the mountains and gradually released.
  
  These climate change-driven phenomena have created a new and unpredictable era for water in the West. Natural systems usually function within a predictable range of variability. Water apportionment, on the Rio Grande and elsewhere, is based on that concept. But staying within these predictable ranges no longer applies because of the unprecedented warming and its impact on natural processes.
  
  These changes make it increasingly difficult to predict how much water will run off and be available as snow melts. In 2021, the snowpack in the Rockies was 85 percent of average, but only 25 percent of the water expected wound up in the streams and rivers — the result of increased sublimation and an arid landscape. In 2020 the snowpack was more than 100 percent of normal, but the flow was only 50 percent.
  
  The Rio Grande is a highly managed river system with multiple dams, diversions, and agreements that regulate its flow and allocation. However, the system is strained by warming, drought, and population growth, which reduce the river’s natural flow and increase its evaporation and consumption.