Story highlights The CNN town hall aired at 9 p.m. ET

Gore says he tried to sway Trump on the Paris Agreement

Washington (CNN) Former Vice President Al Gore said he regrets President Donald Trump's decision to begin withdrawing the United States from a landmark accord on climate change.

"I actually did feel there was a real chance that he might come to his senses and stay in the Paris Agreement," said Gore, who has spent years in pursuit of action on climate change and on Tuesday joined CNN for a town hall, moderated by Anderson Cooper.

Gore met with Trump after the 2016 election at the invitation of Ivanka Trump, and he spoke again with the President by phone in early May. But Gore's -- and Ivanka's -- influence clearly was not enough. After some delay, Trump announced in the Rose Garden in June that he intended to pull the United States out of the climate agreement.

Gore declined to get into the details of his private conversations with Trump, but said those conversations had left him with "reason to believe" Trump would keep the United States in the agreement, but added that thankfully his worst fears about the withdrawal were not realized.

"I was worried that other countries might use it as an excuse to pull out themselves," Gore said. "But I was gratified when the next day the entire rest of the world doubled down on the commitment to meet the terms of the Paris Agreement, and then in this country, so many governors and mayors and business leaders said, 'We're still in.'"

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