Former Vice President Al Gore met with President-elect Donald Trump for what he described as “an extremely interesting conversation” at Trump Tower on Monday.

Gore, who campaigned for Hillary Clinton, declined to say what exactly he and Trump spoke about during the meeting. But he said he met with both the president-elect and Ivanka Trump, who reportedly wants to make climate change one of her signature issues.

"I had a lengthy and very productive session with the president-elect. It was a sincere search for areas of common ground... I found it an extremely interesting conversation, and to be continued, and I'm just going to leave it at that," Gore told reporters after the meeting.

Later Monday, Gore spoke to MNSBC's Chris Hayes and reiterated that he felt good about the meeting, adding "we're in this wait and see period, but I was happy to have the opportunity and to have the exchange of views."

Although he was reluctant to go into detail about his conversation with the President-elect, Gore also praised Ivanka Trump's commitment to the issue, saying her passion was "certainly evident" during the brief conversation they had before his meeting with Trump.

Ultimately, Gore said he believes the momentum and international support built up around climate change will continue no matter the policies of the next administration.

"I think the momentum is unstoppable now, we're winning this — we're going to win it — but there is a serious question as to how fast we will win and that's crucial," he said.

Since leaving public life following his unsuccessful 2000 presidential run, Gore has become one of the best known crusaders in the fight against human-caused climate change.

He hit the campaign trail for Clinton in the final months of the presidential contest, calling her both the best candidate to combat global warming and reminding supporters “every single vote counts.”

Clinton, like Gore in 2000, won the popular vote but lost the electoral college.

Before running for office, Trump called climate change a hoax “created by and for the Chinese.” However, Trump said he has an “open mind” on the issue in an interview with the New York Times last month.