The Van Trump Report

Is the U.S. Sliding Toward a Water Scarcity Crisis?

A new report from the Intergovernmental Panel on Climate Change (IPCC), is a 3,675-page deep-dive into the latest climate change research and the potential impacts to human society. While floods, wildfires, and habitat destruction all play a part, IPCC says the biggest impact will be on agricultural systems.    

Water scarcity, not surprisingly, features prominently in the report’s findings regarding the impacts of climate change on agriculture. The report authors broadly describe water scarcity as “a mismatch between the demand for fresh water and its availability.” Currently, 4 billion out of 7.8 billion people are estimated to experience severe water scarcity for at least one month per year due to climatic and non-climatic factors. Nearly half of these people live in India and China. Although regions with high water scarcity are already naturally dry, the report says climate change is leading to further reductions in water availability in many regions.

Although research does indicate that climate change is likely to bring increasing precipitation in many areas of the contiguous 48 United States, especially in northern regions, other areas are expected to receive less. Furthermore, increasing temperatures, which are expected everywhere in the U.S., will tend to lower streamflow via the effect of temperature on evaporative demand. In some areas, this is expected to completely negate the positive effects of increasing precipitation and lead to decreasing streamflow.

The U.S. Southwest is among the regions that the IPCC says will soon be profoundly different. The Colorado River, which provides water to 40 million people from Denver to Los Angeles, is approaching what the authors call a “tipping point” at which long-term water scarcity conflicts with high water use and farming.

Farmers in California and other parts of the West may already be getting a taste of what’s to come if water scarcity continues to intensify across the U.S. In late February, the United States federal government said it would not deliver water to farmers in California’s Central Valley Project, a network of dams, reservoirs, and canals that irrigates much of the state’s farmland. That follows the first-ever water shortage on the Colorado River declared by the Bureau of Reclamation late last year. It’s the fourth time in the past decade that Central Valley Project’s water resources have been closed to farmers.

Seven states in the U.S. and millions of acres of irrigated farmland depend on the Colorado River for water. Over the past 20 years, the flows of the Colorado River have shrunk by almost -20%, thanks largely to a “megadrought” that is now in its 21st year. Studies predict flows will fall by another -35% or more by 2050. Water supplies in the West’s two most important reservoirs also continue to shrink. At the end of the 2021 water year, Lake Mead, the nation’s largest reservoir, was just 35% full. Lake Powell, the second-largest U.S. reservoir, was less than 30% full. While a wet December helped relieve some of the dryness in the West, more than 95% of the region is nonetheless in some form of drought.

In California, the drought reduced surface water deliveries in 2021 by -5.5 million acre-feet, compared to predrought conditions. As a result, farmers in California’s agricultural belt, which produces roughly a quarter of the nation’s food, fallowed nearly -400,000 acres of additional cropland in 2021. The ongoing water deficit also caused about 1,000 domestic wells to go dry statewide last year. The costs of groundwater pumping have also continued to increase due to a combination of increased demand for well development and lower depth to groundwater levels. The California Department of Food and Agriculture estimates crop revenue losses at $962 million for 2021. Once the spillover effects are considered, region-wide gross revenue losses of $1.7 billion, 14,364 full and part-time jobs, and nearly $1.1 billion in value added are expected.

California depends on winter storms to refill its reservoirs and produce a strong snowpack, which serve as essential water savings accounts relied on through the rest of the year. But so far, the first two months in 2022 have offered little reprieve. If the state doesn’t get more precipitation in March, it is likely that water agencies will be forced to enact even more severe cutbacks to agriculture this year.  

Within as little as 50 years, many regions of the United States could see their freshwater supply reduced by as much as a third, according to a U.S. government-backed study released in 2020. Of all the freshwater basins that channel rain and snow into the rivers from which we draw the water, nearly half may be unable to meet consumers’ monthly demands by 2071. With as many as 96 out of 204 basins in trouble, water shortages would impact not just California and the Southwest, but most of the U.S. That includes the central and southern Great Plains, central Rocky Mountain states, as well as parts of the South and the Midwest. (Sources: National Geographic, CDFA, IPCC, Population and Climate Change Point to Future Water Shortages)

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