You never know dept.: a reluctant poster girl.(The Talk of the Town)(Dana Fisher)

Contrary to what riders waiting for the crosstown bus at Amsterdam Avenue and Eighty-sixth Street have been led to believe, Dana Fisher would not, if she had a million dollars, "buy a car and a cute driver to go with it." That is the quote attributed to her on the New York Lotto ad that dominates the bus shelter. And that is Fisher's smiling face and, alongside it, her first name. But it is not her sentiment. It is, in fact, the opposite of her sentiment. And it has created some controversy among Fisher's colleagues at Columbia University's environmental-policy-studies program.

Fisher is a visiting scholar at Columbia's School of International and Public Affairs, and she studies global climate change. "It's relatively dry and boring," she said the other day. An energetic young woman with wavy dark hair and a quick laugh, she will be presenting a paper this summer at the American Sociological Association's meeting in Chicago, demonstrating, she says, that "vehicle travel per capita is the strongest predictor of CO2 emissions per capita." In other words, individuals driving cars are the biggest culprits in global warming. "I don't have a car or want a car in this city," Fisher said. "I use my dad's car when I need a car."

Fisher's involuntary journey across the ideological spectrum began in December, while she was shopping in Herald Square. "There was a stand set up and they kept playing that 'If I Had a Million Dollars' song" -- the Barenaked Ladies hit that inspired the new Lotto commercials. "The people at the stand said, 'Would you like a drink' -- I think it was a Snapple -- 'and a lottery ticket? Let us take your picture so you can be eligible for our ad campaign.' I'm, like, 'Sure, I'm thirsty.' " In answer to the question "What would you do if you had a million dollars?" Fisher wrote on a sheet of paper, "Establish a foundation that would deal with global environmental issues." "I remember thinking, Maybe they'll pick me, just because I had this very altruistic, socially responsible answer."

Two weeks ago, a student raised her hand in a seminar on climate-change policy that Fisher is teaching, and said, "You know, there's a model who looks just like you in this ad I saw." Since Fisher had never heard back from the Lottery people, who had promised to pay her two hundred ...