Sarah Palin's position about the causes of global warming continues to evolve.
Last September, she told Newsmax magazine that she doesn't think human behavior is one of the causes of climate change:
A changing environment will affect Alaska more than any other state, because of our location. I'm not one though who would attribute it to being man-made.
More recently, she hinted that manmade activities may play a role in global warming, telling CBS News' Katie Couric:
You know, there are man's activities that can be contributed to the issues that we're dealing with now, with these impacts. I'm not going to solely blame all of man's activities on changes in climate because the world's weather patterns are cyclical and over our history we have seen changes there.
But yesterday, Palin was stumped when asked to name a single manmade cause of climate change by reporter Steve Crupi of NBC affiliate News 3 in Las Vegas.
Q: I've also heard you hint that you do think there might be some man-made causes that are contributing to this. Can you describe what those are?
PALIN: Right, well what I have said about this is really the debate at some point, had better shift to, no matter the cause, whether it all be attributed to man's activities or just the natural cycle of climate changes in our earth's history. We have seen this before.