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Within the lifetime of a teenager living today, there will be massive changes from climate change. California offers a clear example.
Rain is rare in California’s Central Valley from April to October. Spring’s melting snowpack has been a critical element of California’s extensive irrigation projects.
A “growing body of research” demonstrates that in coming decades the Sierra Nevada mountains will experience DRAMATICALLY reduced snowpacks. Reduced snowpacks will radically impact the water supplies for thirsty California garden crops marketed nationally, including almonds, fruits and vegetables.
Tom Philpott of ‘Mother Jones’ reports. Jim

“So far, this winter has brought ample snows to the Sierra Nevada, the spine of mountains that runs along California’s eastern flank. That’s good news for Californians, because the range’s melted snow provides 60 percent of the state’s water supply. Anyone in the United States who likes fruit, vegetables, and nuts should rejoice, too, because water flowing from the Sierra’s streams and rivers is the main irrigation source for farms in the arid Central Valley, which churns out nearly a quarter of the food consumed here.

“But the Sierra snowpack has shown an overall declining trend for decades —most dramatically during the great California drought of 2012-2016 — and will dwindle further over the next several decades, a growing body of research suggests. In the latest, published in the peer-reviewed Geophysical Research Letters journal, Lawrence Berkeley National Laboratory researchers lay out what they call a ‘future of consistent low-to-no snowpack.’ In other words, a new normal in which the robust snowpack developing this year would be an almost unthinkable anomaly…

“The results: By mid-century (2039–2059), the average annual snowpack will fall by 54.4 percent compared to the late-20th century baseline. By the time today’s teens are in their 70s, it will be 79.3 percent beneath the old standard. To analyze massive amounts of water, planners think in acre-feet—the amount needed to submerge an acre of land by one foot. At the end of the last century, the Sierra Nevada captured an average of 8.76 million acre-feet. By mid-century, they project, the average will fall to 4 million acre-feet, and by century’s end, 1.81 million acre-feet.

“The Central Valley Project — a federally run network of dams, reservoirs, and canals that waters about a third of California’s irrigated farmland and provides water and electricity to millions of urban users, all from snowmelt — could become what economists called a ‘stranded asset’ in such a scenario: a multi-billion-dollar public investment that lacks sufficient water to perform its tasks.”