The Internet has buzzed with the bold projections on the future of Lake Mead. In 2008 scientists from San Diego’s Scripps Institute based their predictions on “one million-acre feet a year deficit of the Colorado River, massive amounts of evaporation from the lake and the viscous effects of a warming world from climate change.”
Lake Mead is receding to a level not seen since it was first being filled in the 1930s. In 2000, Lake Mead’s level was 1,215 feet above sea level. The lake now is at 1,083 feet. Quiz time: if the level continues to dropping 10 feet a year, how long before the turbines stop spinning when the level reaches 1,050 feet?
The Scripp’s scientists also predicted a 50 percent chance that Lake Mead would run dry by 2021. Still people could reassure themselves that this seemed rather far-fetched. We’re talking the Hoover Dam, the Colorado River, the Rockies. Let’s get back to reality, shall we?
Except UCLA researchers now warn that the next couple years could be even drier. This is a NAGT (Not A Good Thing) for California farmers and for the nation that it helps to feed. While observers have talked about food scarcity from water shortages (for them, not us), increasingly there’s talk about our top agricultural states no longer able to sustain the previous level of agriculture.
There has been news reports that Texas and California have suffered from unprecedented heat and drought, and Professor Joe has noted the irony in that adamant climate denial comes from ‘elected representatives’ of those areas likely to suffer most from Dust Bowl conditions. “Welcome to a drier world,” intones Dr. Reese Halter.
History teaches us that prolonged droughts decimated the Pueblo people of the American southwest and the Angkor of Southeast Asia. Repeated drought cycles annihilated millions of Mayans in Middle America.
Over the last decade, the Southwest has suffered the sharpest temperature increase on the continent, declining late season snowpack, loss of vegetation, billions of bark beetles and rampant wildfires; all the while growing faster than any other region in the United States.
Global warming is predicted to heavily reduce snowfall along the Southern Rocky Mountains by as much as 45 percent over the next four decades.
Winter snowfall accumulates as a snow pack and the high elevation Engelmann spruce, subalpine fir and limber pine forests provide an essential cover so that the snow melts slowly in the springtime and feeds the headwaters of the mighty Colorado River which drains one tenth of the land base in the lower 48 states.
Global warming has not only significantly reduced the Southern Rockies snowpack but it’s melting it three weeks earlier in the springtime. And the result over the past decade has been a startling increase in the number and size of hot-burning wildfires.
Professor Gumption repeated the warning, as did atmospheric scientist Susan Solomon of the National Oceanic and Atmospheric Administration:
The average temperature of the planet for the next several thousand years will be determined this century—by those of us living today, according to a new National Research Council report which lays out the impact of every degree of warming on outcomes ranging from sea-level rise to reduced crop yields.“Because carbon dioxide is so long-lived in the atmosphere, it could effectively lock Earth and future generations into warming not just for decades and centuries, but literally for thousands of years.”
Three climate patterns are all set to collide and produce a major drought. And, this concurrence will mean more food shortages.
Does it mean the end of civilization? Perhaps, it is too soon to tell. It, also, is worth noting the decline in food from our oceans. Oh, and then we have those committed emissions, about which it is very difficult to do anything since there already are there.
Ancient tree rings from pinyon pines have been used as sensitive “listening posts” to determine climate variability and in particular drought. And, what the tree rings are telling us, say the UCLA researchers, is this: When Pacific Ocean sea-surface temperatures plummet as much as 18F La Nina’s occur, lasting for up to 18 months and the Southwest experiences a drought. There’s a 30-year Pacific Decadal Oscillation pattern that also affects climate, when its negative it extends the La Nina and prolongs droughts. There’s a third climate pattern that lasts 60 years called the Atlantic Multidecadal Oscillation, which changes the surface temperature of the North Atlantic. If it’s positive it has little effect on California but when it’s linked up with a negative Pacific Decadal Oscillation, snowpacks in the west decline on average 10 percent and the Colorado River decreases discharge by as much as 18 percent. Incidentally, a positive Atlantic Multidecadal Oscillation also strongly correlates to major droughts in the Midwest, Southwest and the 1930s Dust Bowl.