Israel and Jordan have signed a declaration of intent at the UN climate conference to conserve and protect their shared Jordan River — a sacred waterway nearly running dry because of climate change, pollution and other threats.

The agreement, struck at the Cop27 summit in Sharm El-Sheikh, Egypt, marks an important initial step in co-operation.

Water co-operation was a key element of the 1994 peace treaty between the two countries but chilly relations over recent decades have complicated efforts to increase water supply to the river.

The plan announced on Thursday is short on specifics. It says Israel and Jordan have promised to try to reduce river pollution by building up wastewater treatment facilities and upgrading sewer systems to prevent riverside cities from dumping raw sewage into the waters, according to a statement from the Israeli government.

The two countries also aim to promote sustainable agriculture, control run-off from farm fields and reduce use of pesticides, it added.

“Cleaning up the pollutants and hazards, restoring water flow and strengthening the natural ecosystems will help us prepare and adapt to the climate crisis,” said environmental protection minister Tamar Zandberg.

Jordan’s state-run Petra news agency said the plan aims to increase water supplies and create job opportunities “for those living on both sides of the Jordan River, including Palestinians”.

EcoPeace Middle East, a cross-border environmental group which has promoted Israeli-Jordanian-Palestinian co-operation on water issues, said the agreement to rehabilitate the river was “a critical climate adaptation measure that can help bring back 50% of the biodiversity lost because of decades of pollution and freshwater diversion”.

The waterway separates Jordan to the east from the Israeli-occupied West Bank, seized by Israel in the 1967 Middle East war and sought by the Palestinians for their future independent state.

The water basin is billed as the site where Jesus was baptised, drawing tourist revenue for both countries.

In recent years the once-rushing waters of the Jordan have been reduced to a trickle as population growth and climate change take their toll.

Jordan reported on Thursday that the river’s run-off has plummeted to 7% of what it once was.

Because its waters feed into the Dead Sea, the saltwater lake is now disappearing — its levels dropping by three feet per year.