The nation's top scientists and spies are collaborating on an effort to use the federal government's intelligence assets - including spy satellites and other classified sensors - to assess the hidden complexities of environmental change. The collaboration ... has the strong backing of the director of the Central Intelligence Agency. Secrecy cloaks the monitoring effort ... because the United States wants to keep foes and potential enemies in the dark about the abilities of its spy satellites and other sensors. Controversy has often dogged the use of federal intelligence gear for environmental monitoring. About 60 scientists - mainly from academia but including some from industry and federal agencies - run the effort's scientific side. All have secret clearances. The C.I.A. runs the program and arranges for the scientists to draw on federal surveillance equipment, including highly classified satellites of the National Reconnaissance Office. Officials said the effort to restart the program originated on Capitol Hill in 2008 after former Vice President Al Gore argued for its importance with Senator Dianne Feinstein, Democrat of California, who was then a member of the Senate Intelligence Committee; she became its chairwoman in early 2009.