A Yale/George Mason poll released Monday found that a majority of undecided voters nationwide consider global warming to be “one of several important issues” influencing their vote in this year’s presidential election. Only 1 percent of undecided respondents ranked the issue as the “single most important” of the election, while 37 percent answered it was “not an important issue.” Roughly an equal number of undecideds told pollsters they trusted each of the two candidates, respectively, as sources of information on the topic. The poll, conducted between Oct. 8 and Oct. 14, surveyed 2,189 American adults and also found Obama to be leading McCain by a 46-36 margin.