This is a very long, but a very recommended, article from the NY Times on the drying up of the west. While most of us think of global warming as the ice caps melting and our coastal cities being submerged underwater, it's really much more encompassing than that. Science isn't my forte, but I'll try to sum up the article. In the American West, mountain snowpack (winter snow that falls on the mountains at high altitudes and then melts and seeps down in the spring to provide water) is decreasing every year as a result of climate change. This is bad enough in and of itself, as there's less water to go around for people in California, Nevada and the other states, but the population in many of these states is growing rapidly. So there's going to be less water for more people.
The article discusses this as well as interviews several scientists and water treatment experts who are trying to find solutions to this problem. As places like the Sierra Nevada, the Colorado River and Lake Mead dry up, it becomes problematic in terms of litigation, as there are many contracts between states and localities for water rights.
This is very relevant, especially today, as both the California wildfires and Georgia declaring a state of emergency over its drought are top stories. It's funny how we thought global warming would be a problem for the future generation, but it's fast proving to be a major problem for us.