FORT WAINWRIGHT, Alaska — Vice presidential candidate Sarah Palin’s assertion that she believes humans play a role in climate change — made in her first major interview since joining the Republican ticket — is at odds with her previous statements.

Mrs. Palin said she didn’t disagree with scientists that “man’s activities” can be attributed to the problem.

“Show me where I have ever said that there’s absolute proof that nothing that man has ever conducted or engaged in has had any effect or no effect on climate change. I have not said that,” Mrs. Palin told ABC News in an interview broadcast yesterday and today.

However, in the past Mrs. Palin has said she does not believe global warming is caused by human activity. She has told the Internet news site Newsmax, “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.”

In an interview with a Fairbanks newspaper within the last year, Mrs. Palin said: “I’m not an Al Gore, doom-and-gloom environmentalist blaming the changes in our climate on human activity.” ABC cited the interview as being at odds with her statement.

Senator McCain has said humans have caused climate change.

In the ABC interview, Palin said she believes that “man’s activities certainly can be contributing to the issue of global warming, climate change. … Regardless, though, of the reason for climate change, whether it’s entirely, wholly caused by man’s activities or is part of the cyclical nature of our planet — the warming and the cooling trends — regardless of that, John McCain and I agree that we gotta do something about it.”

Questions about Mrs. Palin’s knowledge of foreign policy dominated the interview with ABC’s Charles Gibson. Mrs. Palin repeated her earlier assertions that she’s ready to be president if called upon, yet she sidestepped questions on whether she had the national security credentials needed to be commander in chief.

Senator McCain has defended his running mate’s qualifications, citing her command of the Alaska National Guard and Alaska’s proximity to Russia.

Pressed about what insights into recent Russian actions she gained by living in Alaska, Mrs. Palin told Mr. Gibson, “They’re our next-door neighbors and you can actually see Russia from land here in Alaska, from an island in Alaska.”

Mrs. Palin, 44, has been Alaska’s governor for less than two years and before that was a small-town mayor. Asked whether those were sufficient credentials, Mrs. Palin said: “It is about reform of government and it’s about putting government back on the side of the people, and that has much to do with foreign policy and national security issues.”

She said she brings expertise in making the country energy independent as a former chairman of the Alaska Oil and Gas Conservation Commission.

Mrs. Palin said that other than a trip to visit soldiers in Kuwait and Germany last year, her only other foreign travel was to Mexico and Canada. She also:

—Appeared unsure of the Bush doctrine — essentially that America must help spread democracy to stop terrorism and that the nation will act pre-emptively to stop potential foes.

Asked whether she agreed with that, Mrs. Palin said: “In what respect, Charlie?” Gibson pressed her for an interpretation of it. She said: “His world view.” That prompted Gibson to say “no, the Bush doctrine, enunciated September 2002, before the Iraq war” and describe it to her.

“I believe that what President Bush has attempted to do is rid this world of Islamic extremism, terrorists who are hell bent on destroying our nation,” Mrs. Palin said, though she added “there have been mistakes made.”

Pressed repeatedly on whether America could attack terrorist hideouts in Pakistan without the country’s permission, she said: “If there is legitimate and enough intelligence that tells us that a strike is imminent against American people, we have every right to defend our country. In fact, the president has the obligation, the duty to defend.”

—Said nuclear weapons in Iran’s hands are dangerous, and said “we’ve got to put the pressure on Iran.” Asked three times what her position would be if Israel felt threatened enough to attack Iranian nuclear facilities, Mrs. Palin repeatedly said America shouldn’t “second guess” Israel’s steps to secure itself.

—Called for Georgia and the Ukraine to be included in NATO, a treaty that requires America to defend them militarily. She also said Russia’s attack into Georgia last month was “unprovoked.” Asked to clarify that she’d support going to war over Georgia, she said: “Perhaps so.”

On the environment, Mrs. Palin said she disagreed with McCain’s position against oil drilling in the Arctic National Wildlife Refuge in Alaska.

“We’ll agree to disagree,” she said, “but I’m gonna keep pushing that and I think eventually we’re all gonna come together on that one.”