In 1978 the Dead Sea turned over for the first time in centuries. For millennia, this terminal lake at the lowest point on the Earth's surface had been receiving the sweet waters of the Jordan River, losing only pure water to relentless evaporation and collecting the salts left behind. The result had been an inhospitably briny lake eight times saltier than the sea, topped by a thin layer of the Jordan's relatively less-dense fresh water. The two salinity levels of the river and the lake kept the Dead Sea in a perpetually layered state even while the lake level remained fairly constant – evaporation from the lake surface occurs at roughly the rate of the natural flow of the Jordan and other tributaries and springs.

These delicate balances were disrupted as modern nations – with all of their human and economic needs tied inexorably to the local supply of fresh water – built up along the shores of the Jordan. In the past century, as both Jewish and Arab nationalism focused on this historic strip of land, the two peoples locked in a demographic race for numerical superiority. As more and more of the Jordan was diverted for the needs of these new nations, the lake began to drop, most recently by about one-half meter per year.