It’s been ridiculously hot along the unstoppable shrinking shoreline at Lake Mead. Over the past four days, highs have peaked at a scorching 109 to 111 F (42 to 44 C). Similar heat blasted all up and down the Colorado River Basin, squeezing moisture out of a key water supply for 25 million people in California, Arizona, and Nevada.

(NASA predicts that 20-30 year droughts in the US West will become 80 percent more likely due to human-forced warming. For Lake Mead, the reality of mega-drought appears to already be settling in.)

But these record hot days are just the most recent of many for the river and its water. For over the past 16 years the Colorado River has been assailed by drought. A new kind of mega-drought that has almost certainly been spurred by a human-forced warming of the world. A condition of endemic drying that will…