The megadrought that has devastated the southwestern United States and parts of Mexico over the past two decades is the worst drought the region has seen in at least 1,200 years, according to a study released Monday.
Researchers at Nature Climate Change analyzed tree rings, which determine soil moisture levels over a period of time, and concluded that the current megadrought is worse than the one that hit the region in the late 1500s and is the worst since 800 year of our era.
The study, which analyzed a region stretching from southern Montana to northern Mexico and from the Pacific to the Rocky Mountains, found that human-induced global warming accounts for more than 40% of drought severity.
“A drought at the turn of the 21st century would not have been a megadrought trajectory without anthropogenic climate change,” according to a study by Pak Williams, an assistant professor at the University of California, Los Angeles.
The megadrought ravaging the US southwest and parts of Mexico is the worst drought the region has seen in at least 1,200 years, researchers said Monday.
The above map shows the intensity of the drought in the western United States.
Over the past decade, California and other Western states have experienced severe water shortages, leading to occasional restrictions on water use and forcing some communities to import bottled water for drinking.
The occasional heavy snow or rain was not enough to make up for this.
Last year was especially dry. As of Feb. 10, 95% of the western US was suffering from drought, according to government agency Drought Monitor.
Last summer, North America’s two largest reservoirs, Lake Mead and Lake Powell, reached their lowest levels on record in more than a century.
According to the data received, the current drought is likely to last at least a couple of years, and possibly longer.
Running simulations based on 1,200 years of soil moisture data, the researchers calculated a 94 percent chance that the drought would last until 2022.
There is a three out of four chance that it will last until the end of the decade.
Tree-ring analysis shows that the area west of the Rocky Mountains from southern Montana to northern Mexico was repeatedly subjected to so-called megadroughts lasting at least 19 years between 800 and 1600.
Earlier research has shown that the period 2000-2018 was likely the second worst drought since 800, giving way to a drought in the late 1500s.
The chart above shows the monthly change in the world’s land area affected by severe drought since 1950.
Data from 2019-2021, backed up by new climate models released last year, showed the current drought is worse than any medieval drought.
But without climate change, it “will not compare to the mega-droughts of the 1500s, 1200s or 1100s,” Williams said in a statement.
“Basically, half of the severity of the ongoing megadrought is just warming temperatures, and without that warming, the drought might not have been a megadrought at all,” UCLA climate scientist Daniel Swain told ABC News in June.
Western North America is not the only region suffering from increasingly severe dry spells.
Climate change exacerbated the El Niño-induced drought of 2015-2016, leading to widespread crop failures, livestock deaths, outbreaks of Rift Valley fever, and increased rates of malnutrition.
Between 800 million and three billion people worldwide are projected to experience chronic water stress due to drought caused by warming two degrees Celsius above pre-industrial levels, according to a draft 4,000-page Intergovernmental Panel on Climate Change (IPCC) report on climate impact observed by AFP. .
In a 4C world, that figure reaches four billion people.
The Earth’s surface has already warmed by an average of 1.1 degrees Celsius and will almost certainly exceed the 1.5 degrees Celsius limit of the Paris Agreement within two decades.
Other natural extreme weather events exacerbated by global warming include deadly heatwaves, flooding rains and hurricanes.