Sen. Marco Rubio of Florida, a GOP star and possible 2016 presidential contender, does not believe human activity is causing climate change, he said Sunday.
"I do not believe that human activity is causing these dramatic changes to our climate the way these scientists are portraying it," Rubio said on ABC's "This Week."
"I do not believe that the laws that they propose we pass will do anything about it, except it will destroy our economy," he added.
A National Climate Assessment released by the White House last week found that Rubio's home state of Florida is one of the most vulnerable to rising sea levels and changes in temperatures and storm patterns. President Obama has proposed several new regulatory programs to reduce emissions of carbon dioxide, which most scientists say are the chief cause of a warming global climate.
Rubio said he doesn't agree that actions humans take today could affect how the climate is changing.
"Our climate is always changing," Rubio said. "And what they have chosen to do is take a handful of decades of research and say that this is now evidence of a longer-term trend that's directly and almost solely attributable to manmade activities."
Rubio, who was swept into the Senate in 2010 on a wave of support from tea-party Republicans in Florida, just completed a swing through New Hampshire, the first state that will hold a presidential primary in the 2016 race for the White House. Although he has been a rising star in the GOP, his popularity among conservatives slipped last year after conservative commentators battered him for his role in the Senate's passage of immigration reform legislation last year. (The Republican-controlled House has refused to take up the bill.)
Rubio's denial that human activity is to blame for climate change could stand him in good stead with the conservatives who dominate some Republican nomination contests, although it puts him at odds with the views of most Americans.
About two-thirds of American adults said last fall that they believed there was "solid evidence the Earth is warming," according to a poll by the Pew Research Center. But among Republicans who said they identified with the tea party, only one in four agreed with that statement.
Asked about the cause of climate change, just over 40% of American adults in the Pew survey blamed human activity and one in five took the position that Rubio appears to have adopted -- that change in the climate results from natural patterns of climate variation. Another one in eight said that climate change was "just not happening," and the remaining 17% said they did not know.
But among tea-party Republicans, the largest share -- just over 40% -- said climate change was "just not happening," and fewer than one in 10 said that it was taking place and human activity was to blame. Meanwhile, 14% blamed natural patterns, and about one-third said they did not know.
The views of non-tea-party Republicans in the poll fairly closely resembled those of adults as a whole, although they were a little less likely to blame human causes. Democrats overwhelmingly said that they believed warming was a real problem and that human activities were the prime cause.
Rubio, who turns 43 this month, said he believes he is ready to be president. He said he would make a decision at the end of this year about whether to run.
He criticized Hillary Rodham Clinton, who is widely seen as the Democrats' most likely candidate for president. Rubio said he would give her an "F" for her performance as secretary of State "because if you look at the diplomacy that was pursued in her time in the State Department, it has failed everywhere in the world."
Clinton has been under fire from Republicans for how she handled the Sept. 11, 2012, attacks on the U.S. consulate in Benghazi, Libya that killed four Americans.