Former CNN host Piers Morgan was among those in the trust camp, for instance, tweeting, "Don't agree with President Trump's decision re #ParisAccord but sounds to me like he's just trying to cut a better deal."
Others were clearly sceptical.
"In a dramatic announcement from the White House Rose Garden," New Yorker satirist Andy Borowitz wrote, "Donald J. Trump pronounced the planet Earth a 'loser' and vowed to make a better deal with a new planet."
And then there was John Kerry, who helped negotiate the accord when he was Secretary of State under President Barack Obama.
NBC's Chuck Todd was grilling Kerry on whether, in hindsight, he wishes he'd made the deal a little less vulnerable to reversal by future presidents.
"We presumed that common sense, that basic economics, that science would ultimately prevail," Kerry said.
So how about that new deal that Trump wants, Todd asked.
More like no deal, Kerry said.
"He's going to go out and find a better deal?" he said. "That's like, I mean, that's like OJ Simpson saying he's going to go out and find the real killer."
Kerry meant the former football star's infamous statement after his acquittal on murder charges in the 1990s - that "when things have settled a bit, I will pursue as my primary goal in life the killer or killers who slaughtered" his ex-wife and her friend.
"Everybody knows he's not going to do that because he doesn't believe it," Kerry told Todd. "Because if he did believe in it, you wouldn't pull out of Paris."
Just as no one knows the fate of the Paris accord or its potential replacement, it's unclear how much Simpson actually did to find new suspects for crimes that many people still think he committed.
A few years after his acquittal, a civil jury ordered Simpson to pay millions in a wrongful-death lawsuit. He is in prison for armed robbery, kidnapping and assault, among other charges, after an altercation over sports memorabilia.
Last year, a friend and former manager of Simpson's told a radio station that they did, in fact, track down the real killer - and even tried to take their information to police. But nothing apparently came of it, and the friend would not reveal the real killer's name.