While 14 candidates have thrown their support behind the idea, according to 350 Action's 2020 Climate Test, California Senator Kamala Harris was the first to endorse it on the debate stage, The Atlantic reported.

When asked about her climate change plans, Harris corrected moderator Chuck Todd, saying the proper term was "climate crisis" because "it's an existential threat to us as a species."

"That's why I support a Green New Deal," she said. "It's why on day one as president, I will reenter us into the Paris agreement."

.@KamalaHarris: "I don’t call it climate change. It’s a climate crisis.

"That is why I support a Green New Deal."

Us: 🙌🙌🙌🙌🙌🙌🙌🙌🙌🙌🙌🙌 pic.twitter.com/mMtPsYzYSc

— Sunrise Movement 🌅 (@sunrisemvmt) June 28, 2019

However, Atlantic writer Robinson Meyer noted that she offered no details on what a Green New Deal would look like before switching to a discussion of President Donald Trump's handling of North Korea.

"There's a marked difference in the fluidity of the way moderators and candidates talk about climate change versus how they talk about other issues," Time writer Justin Worland responded in a Tweet.

There's a marked difference in the fluidity of the way moderators and candidates talk about climate change versus how they talk about other issues https://t.co/bjZdlYzybU

— Justin Worland (@JustinWorland) June 28, 2019

Overall, the second half of the Democratic debate was another disappointment for climate action advocates, who have called on the Democratic National Committee (DNC) to hold a climate-focused debate. So far more than 200,000 people have signed a petition demanding such a debate, as HuffPost reported, but DNC Chair Tom Perez has refused.

The first debate on Wednesday, which saw half of the crowded primary field face off, only dedicated around seven minutes to the issue. The second half of candidates discussed it for around eight minutes Thursday, according to climate-focused candidate and Washington Governor Jay Inslee.

"Fifteen minutes in four hours. The DNC will not address the climate crisis with the urgency it requires. We must hold a climate debate. Now," he tweeted.

Eight minutes tonight. Seven minutes last night. Fifteen minutes in four hours. The @DNC will not address the climate crisis with the urgency it requires. We must hold a #ClimateDebate. Now. #DemDebate2

— Jay Inslee (@JayInslee) June 28, 2019

The climate-focused part of Thursday's debate also saw South Bend, Indiana Mayor Pete Buttigieg, former Vice President Joe Biden and former Colorado Governor John Hickenlooper offer ideas.

Buttigieg promised a carbon price and emphasized the role that rural America could play by instituting carbon-trapping farming practices, HuffPost reported.

"This is not just happening in the Arctic ice caps. This is happening in the middle of our country," he said, according to The Washington Post.

Biden said that even if Congress would not back him, he would add 500,000 electric vehicle charging stations across the U.S. and earmark billions towards scientific research. He also emphasized his international experience as vice president, saying he would return the U.S. to the Paris agreement and encourage other countries to increase their commitments.

"We have to have someone who knows how to corral the rest of the world," Biden said, according to The Washington Post.

Hickenlooper was actually the first candidate to mention the Green New Deal, according to The Atlantic, but he dismissed the idea as socialism, HuffPost reported. He said he would work with the oil and gas industry to reduce emissions as quickly as possible.

Independent Vermont Senator Bernie Sanders took the opposite approach to the fossil fuel industry.

"Scientists tells us we have 12 years before irreversible damage. We have to come together against this common enemy, and transition the world off fossil fuels," he said, according to the Sunrise Movement.

"Scientists tells us we have 12 years before irreversible damage. We have to comer together against this common enemy, and transition the world off fossil fuels." —@BernieSanders

yes boi #DemDebate2 #ClimateDebate pic.twitter.com/8yrONbmHYA

— Sunrise Movement 🌅 (@sunrisemvmt) June 28, 2019

Candidates also had a chance to show how much they prioritized climate when Todd asked them what they would seek to accomplish if they could do only one thing, The Guardian reported.

Colorado Senator Michael Bennet and Hickenlooper both said climate change, while author Marianne Williamson said she would call the prime minister of New Zealand to get her advice on dealing with the climate crisis. Businessman Andrew Yang said he would institute a universal basic income, which would help address climate change.

Climate Change Is So Much More Than a 'Single Issue' https://t.co/5MlfJQes4N #Climatechange #Climatecrisis #2020election pic.twitter.com/s0pLLtBS9k

— Renewable Search (@RenewableSearch) June 11, 2019