WASHINGTON, Dec. 23 — In a novel legal action, the City Councils of Oakland, Calif., and Boulder, Colo., have voted to join Friends of the Earth and Greenpeace in a lawsuit charging two federal agencies with failing to conduct environmental reviews before financing projects that the cities say contribute to global warming. The lawsuit contends that the agencies — the Export-Import Bank and the Overseas Private Investment Corporation — have provided $32 billion in financing and insurance over the last 10 years for fossil-fuel extraction projects overseas like oil fields, pipelines and coal-fired power plants without assessing the contribution those...