As scientific warnings of dire climate change-induced drought grow, many in Israel and Jordan cast worried eyes at the river running between them and the critical but limited resources they share.
This month the UN's Intergovernmental Panel on Climate Change showed unequivocally that the climate is changing faster than previously feared, heaping pressure on finite water supplies even as demands grow greater than ever before.
But experts say that instead of provoking argument, Israel and Jordan could be poised for an unprecedented boom in water cooperation amid technological advancements, climate pressures and stronger ties.
Warnings about looming "water wars," including in the Middle East, were often inflated, said Duke University professor Erika Weinthal.
"Water is a resource that allows for adversaries to actually find ways to cooperate," said Weinthal, a specialist in global environmental politics, who has worked extensively on Israel-Jordan issues.
Jordan is one of the world's most water-deficient countries, suffering from extreme droughts, and water cooperation with Israel long pre-dates a 1994 peace deal between them.
The issue came to prominence in 1921, when Pinhas Rutenberg, a Russian Jewish engineer who had moved to Palestine, convinced British authorities and Hashemite royals to approve a hydropower station where the Yarmuk tributary meets the Jordan River.
Solar power for water swap?
Water deals, like all bilateral ties, suffered in recent years under former Israeli prime minister Benjamin Netanyahu, whom critics have accused of neglecting Jordan as he pursued deeper ties with Iran's foes in the Gulf.
But there have been signs of progress since Prime Minister Naftali Bennett's government took office in June, with the countries agreeing to their largest-ever water transaction.
New technologies reducing costs have made seawater desalination "a profitable concern," with investors from Israel, Jordan and the UAE showing interest, said Gidon Bromberg, Israeli director at EcoPeace Middle East.
Multiple assessments show Israel does not have enough land to ramp up the necessary solar production, so will have to buy solar power from Jordan to hit its targets.
"For the very first time, all sides will have something to sell and something to buy," said Bromberg, whose organisation works in Israel, Jordan and the Palestinian territories.
This unprecedented alignment of interests could help repair semi-fractured diplomatic relations, he argued.
The July deal binds Israel to sell an additional 50 million cubic metres of water to Jordan.
