

Sen. Marco Rubio (R-Fla.) in January 2014 (J. Scott Applewhite/AP)

Florida Sen. Marco Rubio (R) acknowledged that the climate is changing, but said that there is no legislative proposal currently on the table that would put a stop to it, while speaking Tuesday at the National Press Club.

"Headlines notwithstanding, of course the climate is changing. The climate is always changing and that is a measurable that you can see. There is climate change." Rubio said. "The issue is whether there is legislative proposals before us that can do anything about it, what I have said and what I disagree with is the notion that if we pass cap and trade it will stop this from happening."

Rubio made headlines over the weekend when he told ABC News that the impact of man-made climate change is being overstated.

"I do not believe that human activity is causing these dramatic changes to our climate the way these scientists are portraying it," Rubio said.

Rubio was asked three times by the National Press Club audience about those climate change comments.

"There are things that we can do to become more efficient in our use of energy, there are things we can do to develop alternative forms of energy, there are things we can do to become better stewards of the energy resources that we have," Rubio said. "But for people to go out and say 'if you pass this bill that I am proposing this will somehow led us to have less tornado and less hurricanes' that's just not an accurate statement and that's what I take issue with."

Rubio's expansion Tuesday on his previous climate change remarks, as well as responses about the 2016 presidential election and immigration reform, came after Rubio delivered a speech on social security during a luncheon at the National Press Club.

The Florida senator, who drew scorn from some of the most conservative members of his party by backing comprehensive immigration reform, doubled down on the sentiment that the immigration system is broken.

"I regret that we didn't get more support for it because it's an important issue that we've got to tackle," Rubio said. "For this country to move forward in the 21st century it needs to solve this...as a sovereign country and for our national security we need to have immigration laws we can enforce. And we need to address that we have 12 million people living in this country illegally. And we have to address it in a way that's responsible and reasonable."

In the speech, Rubio called for overhauls to both the social security and Medicare systems -- including an elimination of the Social Security payroll tax, allowing public enrollment in the same government savings plan provided to members of Congress, and gradually raising the retirement age.

"The answer is to gradually increase the retirement age for future retirees to account for the rise in life expectancy," Rubio said. "And if we act soon, we can do this without changing the retirement age for people who are currently over the age of 55."

The speech was the latest in a series of policy addresses by Rubio, who is attempting to strengthen his policy credentials as he ponders a 2016 presidential run.

Asked about his presidential ambitions, Rubio said that if he seeks the GOP nomination, he will not simultaneously seek another office. He also said he will not base his decision on whether or not to run on the decision of former Florida governor Jeb Bush.