Finally, we have a top administration official telling it like it is. Energy Secretary and Nobelist Steven Chu told a Los Angeles Times reporter:
In a worst case, Chu said, up to 90% of the Sierra snowpack could disappear, all but eliminating a natural storage system for water vital to agriculture.
“I don’t think the American public has gripped in its gut what could happen,” he said.
Precisely. [You can listen to an interview with the LAT reporter and me on "To the Point" here.]
We face desertification of perhaps a third of the earth that is “largely irreversible for 1000 years” — if homo sapiens are not sapiens enough to sharply and quickly reverse emissions trends. Part 1 looked at the canary-in-the-coal mine for desertification: “Australia faces collapse as climate change kicks in.”
But the Southwest from Kansas and Oklahoma to California are right behind Australia, according to a 2007 Science (subs. req’d) paper:
Here we show that there is a broad consensus among climate models that this region will dry in the 21st century and that the transition to a more arid climate should already be under way. If these models are correct, the levels of aridity of the recent multiyear drought or the Dust Bowl and the 1950s droughts will become the new climatology of the American Southwest within a time frame of years to decades.
[Note: That study "only" modeled the A1B emissions scenario, which leads to 720 ppm by 2100. We are currently on track to 1000 ppm (see here).]
A December US Geological Survey report also warned that the SW faces “permanent drying” by 2050.
Before the permanent drying — aka a desert — sets in, you’d expect to see more and longer record-breaking droughts. In fact, Lester Snow, Director of California’s Department of Water Resources said Friday
Fundamentally, California and the SW face one of the gravest dangers predicted by climate science, the expansion of the subtropics, the dry regions of the planet getting drier and getting bigger. As New Scientist explains: