Scientists have discovered evidence deep below the Dead Sea bed of severe droughts that took place 10,000 years ago and more than 100,000 years ago, according to a new report. They believe that their findings are a warning of what could happen in the region if climate change predictions come true.
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The report, published this week in the journal Earth and Planetary Science Letters, is based on research by scientists in six countries, including Israel. It involved the extraction about six years ago of sediment cores from a depth of 450 meters under the Dead Sea bed (almost 1,150 meters from the lake’s surface). Long salt cores were also extracted.
“The cores were sent to Germany for testing, and using radioactive methods we were able to date the period of each section of the core,” said Prof. Mordechai Stein of the Geological Survey of Israel and the Hebrew University of Jerusalem, one of the leaders of the Dead Sea scientific drilling project. The researchers discovered that significant parts of the core are made of salt, which represent periods when the level of the Dead Sea dropped, and that reflects periods of drought in the Dead Sea drainage basin, Stein said.
“These are like time capsules. Chemical analysis allows us to analyze the changes that have taken pace in the sea,” he added.
Analysis of the cores showed that in certain eras, ranging from 115,000 to 130,000 years ago, during the time known as the “last interglacial period” (the period between two ice ages), the level of the Dead Sea plummeted. This attests to previously undocumented severe and long-lasting droughts. During those periods, temperatures rose more than 4 degrees above the average in the 20th century. This is a spike similar to what is predicted due to climate change until the end of this century.
The Dead Sea level rose again when a colder, wetter period began, and declined once more after another drought 10,000 years ago. By analyzing the salt cores, the researchers were also able to estimate how much water reached the sea during the drought. It is believed to have been only 70 percent to 80 percent of the water that flowed to the sea before Israel and Jordan began exploiting the sources of the Jordan and Lake Kinneret.
The decline sometimes persisted for decades or longer. In some periods, the level went down to nearly 500 meters below sea level. In recent years, it has dropped below 430 meters below sea level. Rainfall during the droughts was at least 40 percent less than it is now.
“The observations show that this region is one of the most influenced by climate changes today,” according to Dr. Yael Kiro, an Israeli researcher at Columbia University in the United States and the Hebrew University, one of the report’s authors.
Because what happened in the past can happen again, the new findings can have major implications for the future of water resources and population density in the Middle East, the report concludes.
The Dead Sea level has declined in recent years as a result of human activity, but it is expected to decline even more sharply due to climate change. Israel and Jordan are working on a project to bring remnants of desalinated water from the Gulf of Eilat to the Dead Sea, but the extent of the project is such that it will do no more than slow the decline.