Washington ? Scientists say evidence from around the globe clearly shows that human activity is changing the climate. Conservative Republican candidates in U.S. Senate races nationwide, however, don’t agree.

It’s a point that scores well with tea party activists, but contradicts what NASA, the National Academy of Sciences and other prominent science organizations have been telling readers on their websites.

Victories by these candidates Tuesday could make Senate action on reducing emissions of greenhouse gases — already stalled — even more unlikely to restart next year. Still, even with the complex energy and climate bill looking dead, Republicans have used it — especially the cap-and-trade part about reducing emissions — to bash Democrats. In doing so, they’ve also cultivated uncertainty about climate change.

Beyond that, some Republican candidates also are denying that man-made climate change is real.

John Raese, the Republican candidate in West Virginia, put it bluntly in a debate this month when he spoke of the “myth of global warming and the other myth that man is causing global warming.”

Some others:

• Florida: Republican Marco Rubio questions whether global warming is man-made.

• Missouri: Republican Roy Blunt, in a recent debate, said: “I think climate change is real. I don’t know how much of it is being instigated by people.”

• Alaska: Republican write-in candidate and incumbent Sen. Lisa Murkowski, in a debate Wednesday, said climate change is “one of the tough issues before us” that must be addressed with emissions reductions, but that she opposed the cap-and-trade bill the Senate was considering until this summer.

Tea party Republican Joe Miller, who beat her in the primary, doesn’t think global warming is real. “The science supporting man-made climate change is inconclusive,” Miller says on his website.

• Kentucky: Republican candidate Rand Paul, when asked whether human activity was making the planet warmer, replied: “I think it’s complicated, first of all. And I think anyone who makes an absolute conclusion is probably overstating their conclusion.”

• California: Republican Carly Fiorina was asked at a meeting with Sacramento Bee reporters in March, “Do you believe in man-made climate change?” She replied: “I don’t know. I don’t know. But I think we should have the courage always to examine the science.”

Some Democrats fight back by citing arguments from scientists. “The science is overwhelming,” said Rep. Baron Hill, D-Ind., an House Energy and Commerce Committee member in a close race in a conservative district. “There is no question about that.”