It was an unusual litmus test for a Republican primary debate, one that quickly descended into personal attacks and obfuscation: The candidates were asked whether humans had contributed to climate change.
There is no scientific dispute that the answer is yes, but hardly any of the Republican candidates gave a straight answer.
Before they could raise their hands, Gov. Ron DeSantis of Florida broke in.
“Look, we’re not schoolchildren,” he said, rejecting the idea of a show-of-hands response. “Let’s have the debate.”
The line of questioning from the moderators, Bret Baier and Martha MacCallum, was about the devastating wildfires in Maui and a recent tropical storm that caused flooding in Southern California. They mentioned rising ocean temperatures and played a clip from a young conservative, who asked how the Republicans running for president could assuage young people’s concerns about climate change.
Mr. DeSantis, a distant second in the polls to former President Donald J. Trump, who skipped the debate, deflected and criticized President Biden’s response to the wildfires in Hawaii.
Vivek Ramaswamy, the millionaire entrepreneur whose campaign has dabbled in conspiracy theories, seized on the moment to deny the scientific consensus on climate change.
“Let us be honest as Republicans — I’m the only person on the stage who isn’t bought and paid for, so I can say this — that climate change is a hoax,” he said.
Mr. Ramaswamy added, “And so the reality is more people are dying of bad climate change policies than they are of actual climate change.”
Chris Christie, the former New Jersey governor, admonished Mr. Ramaswamy, whom he sparred with frequently throughout the night.
“I’ve had enough already tonight of a guy who sounds like ChatGPT,” Mr. Christie said, referring to the artificial intelligence chatbot.
He then compared Mr. Ramaswamy’s frequent mentions of his skinny frame and his “odd” last name to the rhetoric former President Barack Obama used when he first vaulted onto the national political stage.
“And I’m afraid we’re dealing with the same type of amateur,” he said.
Nikki Haley, the former South Carolina governor and United Nations ambassador under Mr. Trump, sought to reset the conversation.
“Is climate change real?” she said. “Yes, it is. But if you want to go and really change the environment, then we need to start telling China and India that they have to lower their emissions.”