Last night's debate between vice presidential candidates Joe Biden and Sarah Palin showcased their differences on energy policy and climate change, and also reminded us of some intra-ticket differences on those key scientific issues.

Palin, the Republican governor of Alaska, reiterated that she does not believe that global warming was solely caused by humans, a softer stance than that of running mate John McCain as well as that of the International Panel on Climate Change, which determined that it is "very likely" man-made. As Palin told Katie Couric on the CBS Evening News earlier in the week, climate change is a problem, but people are not the only culprits.

"I'm not one to attribute every man — activity of man -- to the changes in the climate. There is something to be said also for man's activities, but also for the cyclical temperature changes on our planet," she said last night. "But there are real changes going on in our climate. And I don't want to argue about the causes. What I want to argue about is, how are we going to get there to positively affect the impacts?"

Public fascination with Republican vice presidential nominee, Sarah Palin, extends to her views on the environment, evolution and abortion, and that curiosity has only grown since media access to her has tightened in the month since Sen. John McCain picked the Alaska governor as his running mate.

We have a bit more clarity now, after CBS Evening News anchor, Katie Couric, grilled Palin on last night's broadcast. Although Couric wasn't able to nail down Palin's positions as concretely as she (and voters) may have liked, she brought out some of the candidate's reasoning on controversial science topics.

Newly minted Republican vice presidential nominee Sarah Palin has made clear she's open to teaching creationism in public school science classes and to oil exploration in the Arctic National Wildlife Refuge (ANWR). While her running mate, John McCain, has spoken up on some science issues (pro-off shore drilling, anti-opening ANWR to oil exploration), less is known about his positions than those of his Democratic opponent Barack Obama, who recently answered a series of questions on everything from climate change and energy to stem-cell research.

Some highlights: Obama says he would lift a ban on federal funding of research on embryonic stem-cell lines created after Aug. 9, 2001 -- a measure signed into law by President Bush, who vetoed legislation designed to lift the limit. Obama also supports genetic engineering of plants and "water smart" landscaping over irrigated lawns to conserve H20, according to his responses to questions from Science Debate 2008, a consortium of Nobel laureates and business leaders.

Presumptive Republican presidential nominee John McCain today surprised the nation by picking first-term Alaska Gov. Sarah Palin to be his running mate. At 44, Palin is three years younger than Democratic presidential nominee Barack Obama; she is the mother of five, including a son who is in the Army and a baby born in April with Down syndrome.

By choosing Palin, McCain is clearly hoping to appeal to Hillary Clinton supporters, including women who have been slow to warm to Obama. But it's a big question mark whether they will cotton to Palin's conservative leanings: She is antiabortion and an advocate of drilling offshore as well as in the pristine Arctic National Wildlife Refuge (ANWR).