The Megadrought Is Coming: Climate Scientists Predict Decade Long Droughts For Much of America
Don't shoot the messenger, folks.
A recent research article published in the online journal Science Advances by 2050 major portions of the Southwestern and Great Plains states will suffer from droughts much, much worse than the ones we have seen over the last 15 years. If you think things are at a crisis point, now, just wait. According to the researchers:
[A]n empirical drought reconstruction and three soil moisture metrics from 17 state-of-the-art general circulation models to show that these models project significantly drier conditions in the later half of the 21st century compared to the 20th century and earlier paleoclimatic intervals. This desiccation is consistent across most of the models and moisture balance variables, indicating a coherent and robust drying response to warming despite the diversity of models and metrics analyzed. Notably, future drought risk will likely exceed even the driest centuries of the Medieval Climate Anomaly (1100–1300 CE) in both moderate (RCP 4.5) and high (RCP 8.5) future emissions scenarios, leading to unprecedented drought conditions during the last millennium.
Let's put that in non-specialist terms, shall we.
The coming drought age – caused by higher temperatures under climate change – will make it nearly impossible to carry on with current life-as-normal conditions across a vast swathe of the country.
The droughts will be far worse than the one in California – or those seen in ancient times, such as the calamity that led to the decline of the Anasazi civilizations in the 13th century, the researchers said.
“The 21st-century projections make the [previous] mega-droughts seem like quaint walks through the garden of Eden,” said Jason Smerdon, a co-author and climate scientist at Columbia University’s Lamont-Doherty Earth Observatory.
When someone starts talking about mega droughts that would dwarf any ever experienced in the region in nearly a thousand years, I sit up and take notice. And just to be clear, the droughts in the region during the Medieval era were significant, and likely were a major contributor to the end of one of the longest lasting Pre-Columbian civilizations in the Americas, the "Ancient Pueblo peoples."
For those of you unfamiliar with the "Ancient Pueblo peoples," its civilization in what is now the Southwestern United States lasted for over a thousand years, from at least 100 B.C.E. (some scholars place them in the area as early as 1500 B.C.E.) until roughly 1300 C.E. Their pueblo communities extended throughout the mountains, mesas and grasslands of Southwestern Colorado, Southeastern Utah, Northern New Mexico and Arizona. The most famous of their cliff dwelling sites are ruins found in Mesa Verde National Park.
Their civilization, based on a mix of dry land farming, hunting and trade in pottery goods collapsed sometime around 1300 C.E. in part due to a series of severe droughts that hit the region following a large increase in their population between 700 B.C.E. and 1100 B.C.E. when rainfall patterns were above average for an extended period of time. The loss of water resources was a major factor in their abandonment of their pueblo communities, along with other stresses believed to include including competition from peoples migrating into their traditional range, and increased warfare among various groups of Ancient Pueblo peoples Anasazi themselves.
Nonetheless, there is little doubt of the severity of the droughts the region endured during that time.
New tree-ring records of ring-width from remnant preserved wood are analyzed to extend the record of reconstructed annual flows of the Colorado River at Lee Ferry into the Medieval Climate Anomaly, when epic droughts are hypothesized from other paleoclimatic evidence to have affected various parts of western North America. The most extreme low-frequency feature of the new reconstruction, covering A. D. 762-2005, is a hydrologic drought in the mid-1100s. The drought is characterized by a decrease of more than 15% in mean annual flow averaged over 25 years, and by the absence of high annual flows over a longer period of about six decades. The drought is consistent in timing with dry conditions inferred from tree-ring data in the Great Basin and Colorado Plateau
So, how extreme will be these mega droughts that are being predicted for much of the Western United States, including the regions that provide most of the crops we produce? Pretty damn severe, in the nature of apocalyptic severity. That is not hyperbole from me. It's what the scientists are saying about our future prospects:
Eugene Wahl, a paleoclimatologist at the National Oceanic and Atmospheric Administration in Boulder, Co., called the results "stunning."
"It is clear that they are seeing drought, especially in the Southwest, as being greater than any time in the past," Wahl said. "It is also clear that it is the higher temperatures in the future that is driving it." [...]
According to the new research, droughts in the Southwest and Central Plains will only worsen during the second half of this century. The closest comparison is to the 1930s Dust Bowl or 1950s drought, but lasting 35 years instead of just a few.
"Our results point to a markedly drier future that falls far outside the contemporary experience of natural and human systems in Western North America, conditions that may present a substantial challenge to adaptation," the authors write.
We are talking about extreme drought conditions that will extend from the Mississippi River to California that will last for thirty, forty or more years, literally leave our highly populated, water dependent society in uncharted territory, threatening our civilization's ability to adapt to what will be a radically altered future environment.
No one knows what megadroughts, which can last from 30-50 years, look like. So researchers from NASA and Columbia and Cornell Universities went back 1,000 years to peer confidently into our drier future.
“Our results show it’s very likely, if we continue on our current trajectory of greenhouse gas emission and warming, that regions in the west will be drier at the end of the 21st century than the driest centuries during the Medieval era,” Cook told Quartz.
But just how likely is very likely? The study puts the chances of a megadrought in the central plains and southwest sometime between 2050-2099 at above 80%. That’s compared with just a 5-10% risk from 1950-2000. Even the milder emissions scenario predicts drying comparable to a Medieval-style megadrought in many locations. “This really represents a fundamental shift in the climate in western North America forced by these greenhouse gases—it’s a shift towards a much drier baseline than anything that anyone alive today has experienced,” said Cook. [...]
When asked how a megadrought, if it started today, would affect in the West, Famiglietti said that public water, aquifers, agriculture, rangelands, wildlife and forests would all be at risk. He added: “In California, we’re already in deep trouble. Imagine what the water situation will look like in 2075? Depleted groundwater, decimated agriculture, irreparable damage to ecological habitat. Think apocalypse.”
He’s recently written about the water crisis in California, where he imagined the state as a “disaster movie waiting to happen.” After reading the new study, he told Quartz that it “presents a real doomsday scenario and a situation that is far worse than anything that I had been thinking about.”
That is a very frightening thought, particularly since our political and business leaders seemed to be doing their best to ignore or deny the existence of this threat. If we want our children and grandchildren to have any kind of hope for a sustainable future, one that does not risk total societal collapse, we need to change the way in which our nation currently functions at all levels. Political goals, economic policy and cultural valuers all must change, and that change cannot come soon enough. The current devastation and economic disruption caused by the droughts out West are just a taste of what is to come.
“We need to be thinking about intensifying drought and bringing it into our planning, but I think there are also a lot of opportunities, but it’s going to take more cooperation and more coordination to face the uncertainty of the future,” he told Quartz. “We can’t continue the status quo.”