Republican vice presidential nominee Sarah Palin said Tuesday that global warming is "real," but stressed that it "kind of doesn't matter" whether or not humans are to blame for climate change.

Human activity has "contributed to the issues that we're dealing with now with these impacts" on the earth's climate, Palin, who is Republican standardbearer John McCain's running mate, said in an interview aired Tuesday with CBS News' Katie Couric.

"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 history we have seen changes there.

"But it kind of doesn't matter at this point in the debate what caused it. The point is it's real, we need do something about it."

Palin, who is governor of the vast and remote northern state of Alaska, said communities in her state "feel the impacts more than any other state up there with the changes in the climate and certainly it is apparent."

The 44-year-old mother of five was little known nationally until she burst onto the political scene when Republican presidential candidate John McCain chose her as his shock running in late August.

In interviews prior to McCain tapping her to be on the ticket, Palin has said she does not believe global warming is a man-made problem, putting her at odds with McCain.

Her state is one of the country's largest energy producers and she supports opening a protected Alaskan wildlife refuge to oil drilling -- a position pilloried by environmentalists and some Democratic leaders.

As Alaska governor she has also filed a lawsuit seeking to overturn the current administration's decision to list the polar bear as threatened under the Endangered Species Act.

Climate change has been a contentious issue in US politics since President George W. Bush took office nearly eight years ago. Bush remains the only leader of a major industrialized nation to have refused to ratify the Kyoto Protocol, the most far-reaching international treaty on climate change.

A devout Christian who is fiercely anti-abortion and a paid-up member of the National Rifle Association, Palin electrified McCain's campaign after being plucked from the obscurity of the far north.

But in the past week she has faced widespread ridicule for the few interviews she has given, including a previous sit-down with Couric in which Palin cited Alaska's proximity to Canada and Russia as giving her a solid grounding in foreign policy.