Parched Californians think they have it bad. But people in the eastern’s Mediterranean Levant region — which includes Cyprus, Jordan, Lebanon, Syria, Turkey, Israel and the West Bank and the Gaza Strip areas governed by the Palestinian Authority — have been enduring a drought that began back in 1998.

Now, a new study by NASA, Columbia University and University of Arizona researchers confirms that the drought most likely is the worst that the Mediterranean Levant has suffered in the past nine centuries.

The scientists studied tree rings and historical documents in an effort to reconstruct the region’s water history. They found that the most recent drought is not only longer but about 50 percent drier than the worst period in the past 500 years, and 10 to 20 percent drier than any drought since the 1100s A.D.

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The results were accepted for publication in the Journal of Geophysical Research-Atmospheres, a publication of the American Geophysical Union.

The researchers also studied how drought in the region related to water conditions elsewhere. In most cases, for example, they found that droughts in the Levant corresponded to similarly dry conditions in Western Europe. Historically, that may have been a factor in international conflicts.

“Both for modern society and certainly ancient civilizations, it means that if one region was suffering the consequences of the drought, those conditions are likely to exist throughout the Mediterranean basin,” Kevin Anchukaitis, a co-author of the study and a climate scientist at the University of Arizona in Tucson, said in a press release.

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“It’s not necessarily possible to rely on finding better climate conditions in one region than another, so you have the potential for large-scale disruption of food systems as well as potential conflict over water resources.”

Even if the drought eventually eases, a 2013 study by German scientists concluded that the region’s growing population and its water use may lead to chronic shortages.

Israeli, Jordanian and Palestinian water officials recently met in London to discuss improving their cooperation in coping with the region’s water situation. As this 2015 New York Times article details, Israel for years has invested in desalination plants and recycling waste water, and more than 50 percent of Israeli water needs are now filled by those sources.