Exxon Mobil Corp. shareholders on Wednesday approved a proposal calling for the oil company to disclose the impact on its business of compliance with global climate change guidelines, an issue at the heart of a probe by two state attorneys general. A preliminary tally showed the nonbinding proposal passed with 62.3 percent of ballots cast, the world's largest publicly traded oil company said. The sizable increase over last year's 38 percent support for a similar report signaled the nonbinding proposal was backed by at least some of Exxon's top institutional shareholders.