I've heard a number of people suggesting that Nye made a mistake in debating Ham because people can't be persuaded. I confess I sometimes feel this way, but this has gotten me reflecting on a formative moment in my own intellectual development. As an adolescent I remember adoring any form of debate but also being very open minded as I really just a) didn't have fully formed positions on many things yet, and b) just had never thought about many issues. I just loved the exploration of ideas, any ideas. For example, I would eagerly turn to the editorial section of the newspaper every day when it arrived. I still love ideas, though I'm more set in my positions these days. This was a crucial time in my life where I really could be swayed by evidence on a number of issues. In this connection, I'll never forget a sociology course I took in High School. As a middle class white Jewish boy, I pretty much accepted the standard theory of poverty that held that poor people are just lazy. I had never really thought about poverty, I just assumed the poor had some sort of moral failing.
I'll never forget my sociology teacher, who also happened to be the baseball coach, outlining all the factors that lead to poverty in impoverished areas and how it's a vicious cycle: Underfunded schools, parents who aren't around because they work too much, families with substance abuse policies, lack of economic opportunity in the area, linguistic discrimination, malnutrition that effects cognitive development, staggering debt that prevents one from getting higher education to increase opportunity, lacking the right clothing for job interviews, etc., etc., etc. For me that lecture-- and it was a single lecture! --was a "road to Damascus" moment. The scales fell from my eyes and I saw the world in an entirely different way. My economic politics, such as it was, changed entirely as well.
My point is that a lot of people just don't think much about things, take things for granted because that's all they've ever heard, and that evidence and alternative explanations can have a real impact. This is why what Nye did was valuable. There's a portion of that audience that's just never heard the things he said-- for example about snow accumulation. These things will make sense to them and will potentially be seeds changing their entire worldview. As others have said in this thread, it's not about the person you're debating but the audience and many members of the onlooking audience are more open than we might suspect.
Us secularists are often pessimistic about these things because we spend our time railing against the dogmatists who are already set in their ways. We forget that a lot of people just aren't that reflective or committed to any particular position, that they believe what they believe because that's just what they've always heard, and that when they hear something that makes sense their susceptible to change and persuasion. It's important to me, at least, not to forget this experience and to remember that it's possible for others as well. Remembering this is what keeps me going and articulating things rather than assuming everyone's already heard it or that beliefs can't be changed.