So says a poll [PDF] done by Yale and George Mason Universities. Some highlights:

Nearly two out of three undecided voters say that the presidential candidates’ positions on global warming will influence their vote in the upcoming election, according to a new national survey released jointly today by researchers at the Yale School of Forestry & Environmental Studies and George Mason University.

Consistent with other recent polls, the survey found that 48 percent of registered voters said they will vote or are leaning toward voting for Barack Obama, while 39 percent say they will vote or are leaning toward voting for John McCain. Nine percent of registered voters were still undecided as of Oct. 14.

While few undecided voters rated global warming as the single most important issue that will determine their vote, 62 percent of undecided voters, 64 percent of voters leaning toward McCain and 75 percent of voters leaning toward Obama indicated that global warming is one of several important issues that will influence their vote."Even in the midst of the nation’s financial turmoil, global warming remains an important issue for large numbers of voters," said Anthony Leiserowitz, Director of the Project on Climate Change at the Yale School of Forestry & Environmental Studies.

In the race to earn undecided voters’ trust on the issue of global warming, the two candidates are in a dead heat. Fifty percent of undecided voters trust John McCain as a source of information about global warming and 51 percent trust Barack Obama. "In the closing days of this election, each of these candidates still has an opportunity to make their best case on global warming to these critical voters," said Edward Maibach of George Mason University.

Surprisingly, however, 45 percent of McCain voters and 64 percent of those who are leaning toward McCain distrust their own preferred candidate as a source of information about global warming. By contrast, only 15 percent of Obama voters and 36 percent of those who are leaning toward Obama distrust their preferred candidate on the issue.

The results come from a nationally representative survey of 2,189 American adults, aged 18 and older. The sample was weighted to correspond with US Census Bureau parameters for the United States. The margin of sampling error is plus or minus 2 percent, with 95 percent confidence. The survey was designed by Dr. Leiserowitz of Yale University and Dr. Maibach of George Mason University and fielded October 8 through October 14 by Knowledge Networks, using an online research panel of American adults.