November 1, 2017
In Biblical Land, Searching for Droughts Past and Future
Posted by larryohanlon
Perched on a cliff face in Israel’s Negev Desert, close to where the book of Genesis says the wicked cities of Sodom and Gomorrah were burned with divine fire, geologist Steven Goldstein was excitedly uncovering evidence of events even more ancient. Jackknife in hand, Goldstein carved into soft sediments making up the cliff, exposing layers left year by year going back 70,000 years by a now long-gone lake. Cleaning the face, he pointed out neatly alternating dark and light bands–primarily mud and light-colored minerals, respectively. The dark layers marked wet times, the light ones dry, that he could read and learn from–in essence a book much older than the Bible.
Earlier this year, Goldstein and his colleagues at Columbia University’s Lamont-Doherty Earth Observatory published a study based on similar sediments showing that droughts far worse than any recorded by humans have struck this region. Drilling a core of sediment from below the floor of the nearby Dead Sea, they extracted a record going back 200,000 years. Here they found thick sequences of salt precipitated out during the hottest, driest times, when rainfall in this already sere region apparently plummeted to as little as a fifth of modern levels. This was 120,000 years ago, and again 10,000 years ago, both before the time of the ancient Hebrews and other early civilizations.
The study has modern implications. In recent years, human-influenced climate warming has already measurably reduced rainfall and increased evaporation in the Mideast. At the same time, populations are multiplying. The result: worsening water shortages. According to the United Nations, the world’s 10 water-poorest countries are all in this region–and continued warming is on track to re-create the high temperatures associated with the past megadroughts by the year 2100. According to another recent study out of Lamont, the ongoing civil war in nearby Syria may have been sparked in part by a record 1998-2012 drought probably stoked by global warming.
Israel and its neighbor Jordan, who sit on opposite sides of an uneasy border formed in part by the Dead Sea, already consume practically all available water in the sea’s watershed. As a result, the Dead Sea’s level is dropping fast. Land along its shores, and the infrastructure there, are collapsing. It could be a symptom of what is facing the wider region. Up to now, climate scientists had projected that rainfall could decline another 20 percent by 2100. But the Dead Sea cores suggest that things could become much worse, much faster.
Surrounded by badlands and sand deserts, the landlocked Dead Sea region is the setting for many Biblical narratives, and other more recent historic events. It is also earth’s lowest point on land. Its current shoreline lies about 1,400 feet below sea level; the deepest part of its floor lies another 900 feet down. Fed mainly by the Jordan River drainage, it is a literal dead end for water. It is hot here, and much water that reaches the sea evaporates, leaving behind salt; it is nearly 10 times saltier than the ocean. Precipitated-out salt has built up on its bed and shores for eons–more in drier times, less in wetter ones.
The Jordan River watershed also includes Syria, Lebanon and the Palestinian territories. and due to warming-induced changes in storm patterns, the region has seen about a 10 percent decline in rainfall since 1950. Now, the growing populations of the surrounding countries are sucking out practically all the Jordan’s declining flow before it reaches the Dead Sea. To make up the deficit, they are tapping the region’s declining deep groundwater. Starved of inflow and evaporating faster with mounting heat, the sea’s level is now dropping three to four feet a year–a total of about 130 feet since 1950.
Driving south along the shoreline to the foot of Mount Sodom, we disembarked along a barren slope, where past water action had excavated a narrow cave. Following in on foot, we ended up in a stupendous chimney-like chamber that opened to the sky far above. The walls were made of countless alternating layers of mud and salt. The team estimated these to be 6 million to 7 million years old–remnants of the bed of some pre-Dead Sea water body. Standing on tiptoe, Kiro hammered out samples from as high as she could reach, hoping to find clues to these truly ancient climates. A more thorough investigation would probably have to wait, said Goldstein, until someone comfortable hanging from a rope could rappel from the top of the chimney to sample more layers.
Jutting from the top of a cliff just down the road was a big natural column of similar-looking sediment, pointing into the sky like a giant finger. A sign along the road below said it was “Lot’s Wife”–alleged remnants of the Biblical character who looked back on the burning remnants of Sodom and was turned to a pillar of salt. Stein was skeptical. “Actually, look, you can see it’s a pillar of salt and mud,” he pointed out. At another point, we passed the great fortress promontory of Masada, where 1,000 Jewish defenders committed suicide in the year 72, rather than be taken by a besieging Roman legion. “Those sediments in front of it are 14,000 years old,” said Goldstein helpfully.
The scientists came to a tornado-shaped, seemingly bottomless sinkhole along which the remains of a building foundation teetered. Edging up cautiously, they peered into the blackness. “It’s a manmade environmental disaster,” said Kiro. “It used to be so nice. Coming here now just makes me sad.” She hiked down to the newly formed beach, waded into the shallows and fished out some salt chunks forming on the rocks, to compare with ancient samples.
Following a preplanned route, we presently found a turnoff onto a dirt road leading to a wadi, a narrow canyon carved deep into the ancient rock. On foot just beyond its mouth, we could hear water gurgling, and came upon the startling sight of flowering trees and tall reeds swaying in the breeze. Scattered hidden springs like this have been used for millennia by farmers and nomadic livestock herders who still roam the area.
The following day in the capital city of Amman, we met Marwan Al-Raggad, a 37-year-old hydrologist at the University of Jordan. Al-Raggad, full of facts and figures, gave us a detailed rundown of Jordan’s water woes. Prosperous Israel, he pointed out, is water hungry too, but copes in part through expensive desalination of water from the Mediterranean. Poor, landlocked Jordan, population now 9.4 million, has had no such option.
Amman began pumping groundwater in the 1980s, but its aquifers are dropping; he predicts they will run out in 20 or 30 years. A decade ago, Amman residents could turn on the tap any day of the week; now, it is down to just a day or two a week in many neighborhoods. “Except the ones where rich people and diplomats live–they get water 8 to 10 days a week,” Al-Raggad joked. People fill rooftop tanks for bathing and washing, he said, but don’t dare drink the stuff, because it often looks and smells bad. He estimated that 70 to 90 percent of city residents now drink only bottled water. About 15 percent of the national electricity supply now goes to pumping water, he estimated. Shortages have been exacerbated because Jordan has generously taken in some 1.3 million refugees from the next-door war in Syria–a nearly 20 percent population increase in just a few years.
With international help, in 2018, Jordan hopes to break ground on a canal to bring water from the Red Sea for desalination. Brine left over from the process would be dumped into the Dead Sea, possibly helping prop up its level. But the project is controversial, because it might cause ecological damage to both the Red Sea and Dead Sea, and will not by itself fill the country’s needs. Al-Raggad thinks Jordan will have to buy groundwater from Saudi Arabia, which has bigger, but not endless, reserves.
We drove to the suburbs near the Dead Sea. Here, too, the plunging water table is reshaping the surface. Extensive deep gullies are forming as seasonal rains send surface water rushing over sediments a mile or two from the receding shore. Al- Raggad led us down a path into one gully, but backed off when we heard a pack of wild dogs snarling around the corner.
We drove down nearer to the shore, and Al-Raggad talked his way past a couple of policemen on guard there. Here, our gully reached the sea. To get to the water’s edge, we had to descend a dozen giant stair steps, each about three feet high–each one a beach line formed over a year or so, marking the severe annual drops of the sea’s level. At the bottom, waves lapped up on this year’s temporary beach. Plenty of plastic trash–mostly water bottles–had washed onto shore.