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?"

Democratic veep pick Biden, like running mate Barack Obama, agrees with most scientists that humans are the major cause of global warming. "I think it's clearly manmade," he said. "If you don't understand what the cause is, it's virtually impossible to come up with a solution."

Palin and McCain disagree on at least one other key environmental matter: whether to open the Arctic National Wildlife Refuge (ANWR) to oil exploration. Palin is for it, McCain is against it; when asked how they'd handle their differences, Palin said she would try to persuade McCain to change course.
"What do you expect? A team of mavericks, of course we're not going to agree on 100 percent of everything," Palin said. "As we discuss ANWR there, at least we can agree to disagree on that one. I will keep pushing him on ANWR. I have so appreciated he has never asked me to check my opinions at the door and he wants a deliberative debate and healthy debate so we can make good policy."

Obama opposes ANWR oil searches, but backs limited offshore drilling as part of a broader plan that includes alternative energy sources. Biden did not discuss ANWR last night.

Like their running mates, both veep candidates endorsed caps on Earth-warming carbon emissions (they didn't get into details about whether they should be voluntary or mandatory, or what those caps should be) and clean-coal technology.

For more on where McCain and Obama stand on the environment and energy, check out our chart.

(Image of Sarah Palin/Tricia Ward)