The authors of the study used climate models and soil moisture to predict the “likelihood of dryness” over the next century under various scenarios (e.g. continued increase in greenhouse gas emissions). The 17 computer models used showed a high degree of correlation and so the authors then used data from tree rings to determine weather patterns from the present-day back to the year 1000 AD. One of the study co-authors said in a statement that even the worst megadrought from the past would pale in comparison to 21st-century projections. In particular, the authors used their collected data to determine that continued increases in global temperature would increase the chances of a 35-year of longer “megadrought,” which would affect the Southwest and central Great Plains area of the United States by 2100.
What is the likelihood that such a drought occurs? The scientists believe the chances are above 80 percent if the world continues its “current trajectory of greenhouse gas emissions.” However, the likelihood of such an occurrence does depend on future levels of gas emissions. For example, the chance of a megadrought might drop to between 60 and 70 percent in the Great Plains if countries reduce their emissions to “middle of the road” targets, as described by National Geographic. Unfortunately, even such reductions would not reduce the chance that a megadrought would arrive in the Southwest. As the study’s lead author, Benjamin Cook, said in a statement, “Even at the middle-of-the-road scenario, we see enough warming and drying to push us past the worst droughts experienced in the region since the medieval era.”
Sadly, the effects of such a prolonged dry spell would be catastrophic, affecting everything from agriculture, the economy, ecosystems, health and city water supplies. Already, California has been impacted by many changes in its agriculture and water supply, for example, as it suffers through an ongoing drought that’s the worst in the state’s recorded history. In conditions of severe drought, as clean water becomes scarce, public sanitation and personal hygiene would also decrease, whereas wildfires would become more prevalent, leading to extensive property damages; these are only some potential consequences. The cost to both the economy and individuals could be huge.
According to National Geographic, this present study is only the most recent in a group of studies that has predicted significant challenges for those who make their homes in the American West. As Cook continued in his statement, “The real challenge is whether we can take strategies we have now and apply them to the more severe droughts that are likely in the future.”
(Photo courtesy of Kecko)