The four countries bordering Lake Chad on Friday launched a fund aimed at collecting $100 million to help counter climate change and a devastating jihadist insurgency.
West Africa's largest lake -- whose shoreline is shared by Cameroon, Chad, Niger and Nigeria -- has shrunk by 90 percent since the 1960s, a fall blamed on global warming and poor water management.
The area is a stronghold for Nigerian-based Boko Haram militants, whose decade-old revolt has left thousands of dead and displaced more than two million.
The Lake Chad Basin Commission (LCBC) said the "stabilisation funds" would initially have a proposed budget of around $100 million (around 90 million euros).
The money "will serve as a rapid response mechanism" to help local authorities counter Boko Haram by beefing up basic services and support, it said in a statement.
The two-year project, which will start to unfold in eight regions from September, will rely heavily on external donors.
The fund and the appeal for money were launched on Friday in the Nigerien capital Niamey, on the sidelines of a forum of governors from the eight regions.
Sweden pledged around $8 million (around 7 million euros), the LCBC said, while the European Union (EU), Britain and Germany promised "assistance".
Lake Chad's decline has impoverished many families, prompting young people to join the jihadists.
The UN estimates that 10.7 million people in the region depend on food aid.