American West Megadrought Declared Worst in 1200 Years

As of June 3, 2021, Lake Oroville, California's second-largest reservoir, held only 39% of its full capacity water levels. The bleached exposed banks surrounding the lake show how drastically the water levels have fallen from normal. It is just one of many such catastrophes resulted from the 1200-year megadrought. Image by the Copernicus Sentinel2 Satellite. Photo: Copernicus EU, the European Union Earth Observation Programme, via Twitter

The two-decades-long drought happening now in the west is also one that will keep happening on a regular basis from now on, according to the scientists who carried out this study.

The paper, just published in the peer-reviewed journal Nature Climate Change, declared that the twenty-year period lasting from 2000-2021 in the U.S. western states, “was the driest 22-year period since at least [the year] 800.”

“From 2000 to 2021,” the paper explains in its abstract, “mean water-year (October– September) SWNA precipitation was 8.3% below the 1950–1999 average and temperature was 0.91 °C above average (Extended Data Fig. 1). No other 22-yr period since at least 1901 was as dry or as hot.”

The drought has caused record declines in water levels in Lake Mead and Lake Powell, two of the largest reservoirs in North America, caused in turn by rapid declines in the water flow from the Colorado River. It has also caused soil moisture, a critical measure of water balance which supports trees, natural vegetation, and agriculture, to be “below average in 18 of the of the 22 years from 2000-2021.”

The result of the drought has been massive crop loss, mandatory cutbacks of 20% of the normal allotment of water flowing into the state of Arizona and other regions, and in some regions as much as a 50% loss of freshwater available compared to previous years.

The National Drought Monitor map for the western United States as of February 8, 2022. Of note is that there has been virtually no rain in California for almost all of 2022 to date. Photo: National Drought Mitigiation Center

Even with the presence of an unusually-rich atmospheric river flow into the west near the end of 2021, the paper continues, “the United States Drought Monitor [a national drought tracking data center in the U.S.] classified >68% of the western United States as under extreme or exceptional drought for nearly all of July–October 2021, a record-high proportion of drought extent in the USDM’s 22-yr history.”

Behind the drought is, of course, global heating caused by the climate crisis and ever-increasing greenhouse gas emissions level in the atmosphere which trap solar energy close to the planet. That plus unusual atmospheric conditions and long-tight water supply constraints in the region has pushed the situation to a crisis level. That level may also not ease significantly anytime in the next decades.

It is, the paper declares, the “worse-case scenario [which] already appears to be coming to pass.”

“Anyone who has been paying attention knows that the west has been dry for most of the last couple decades,” explained paper lead author Park Williams, a climate scientist at the University of California, Los Angeles, in an interview about his team’s findings. “We now know from these studies that is dry not only from the context of recent memory but in the context of the last millennium.”

Jason Smerdon, a coauthor of the study and a climate scientist at the Lamont-Doherty Earth Observatory of Columbia University, said their conclusions showed that “these multi-decade periods of dryness will only increase with the rest of the century.”

Smerdon hoped the warning will cause people to realize that “There are pathways we can take that are more sustainable and involve much less risk than the ‘burn, baby, burn’ approach that we would take if we did not do anything.

Among those pathways are numerous advanced technologies to address everything from low-water-consumption farming techniques and, more important, a means of efficiently treating and recycling what is known in the water industry as greywater as well as blackwater.

Both such approaches involve capturing runoff water from everything from cleaning, showers, and even toilet flushing, then treating them and recycling the water back through the same water systems.

Though many approaches were touted in the past as the optimum means of accomplishing this, a new startup known as Climate Survival Solutions, Inc., may have just cracked the code for what it takes to process such water routinely and sustainably on a mass scale.

The key to the technology is the use of algae-based systems to help isolate and filter the water so that undesirable components are separated out while the rest can readily be recycled back. Even the toxic blackwater components are envisioned by the technologists as to be utilized as fuel in the company’s biodiesel reactors, to minimize further waste from the used water and to provide an alternative energy source as a bonus.

The company’s website has multiple white papers and technology briefs on these critical innovations.

With appropriate treatment, as much as 90 percent of the greywater could be recycled after use. In a world where 1200-year megadroughts are about to become ordinary events, reusing the water for everything from bathing to cooking and even drinking will become mandatory.