Updated: August 25, 2014, 3:57 PM

Former Sen. Scott Brown (R), now running for Senate in New Hampshire, over the weekend was pretty clear: science has not proven that climate change is real. But back in 2012, when Brown was running for re-election in Massachusetts, he said that he “absolutely” believed climate change is real and that it is a result of both man-made and natural causes.

Brown and the other candidates in the Republican primary for U.S. Senate in New Hampshire were asked on Saturday “do you believe that the theory of man-made climate change has been scientifically proven?”

Former Sen. Bob Smith, another former senator running to replace Sen. Jeanne Shaheen (D-NH), was first asked if he believed “that the theory of man-made climate change has been scientifically proven?” Smith responded “no.” Then the same question was posed to Brown. Brown said “no” too. The question and answer were flagged by the opposition research organization American Bridge 21st Century.

Brown’s comments strongly conflict with an answer he gave on climate change when he was running against now-Sen. Elizabeth Warren (D-MA) in 2012. Brown was asked if he believed climate change is real, and if so what would should the federal government be doing about it?

“Yes, yes I do,” Brown said. “I absolutely believe that climate change is real and I believe there’s a combination between man-made and natural. That being said one of the biggest things we could do is get an energy policy and we don’t have one.”

In 2009, when Brown was running against Democrat Martha Coakley for U.S. Senate in Massachusetts, Brown also weighed in on climate change with a blurry answer. Coakley said “if you believe there is a climate change issue, then you have to take action.”

Brown responded: “I [have] said the climate is always changing.” He added “The question I have is, is it man-made, or does it just happen naturally?”

TPM has reached out to the Brown campaign for comment.

Listen to Brown’s response at the Saturday event here:

You can see Brown’s answer to the question in 2012 at around 48:00 in the video below: