"It's very dangerous. The U.N. estimates it's 12 years before we deal with much deeper problems," de Blasio, the Democratic mayor of New York City, said during an interview on "Hannity."
"It's very dangerous. The U.N. estimates it's 12 years before we deal with much deeper problems."
"Then what the hell are we arguing for? Let's throw a big party if it's only 12 years," Hannity responded, dismissive of the U.N. report.
"Let's get to work. The Green New Deal gives us that opportunity," de Blasio responded. (New York City has proposed its own local Green New Deal initiative, in addition to the nationwide proposal pitched by Rep. Alexandria Ocasio-Cortez, D-N.Y., and Sen. Ed Markey, D-Mass.)
De Blasio and Hannity sparred, going back and forth over the climate-change proposal's impact on the coal, oil and natural gas industries, with Hannity telling the candidate that it would impact the country negatively.
"I'm recognizing a truth that you fail to recognize, that every economy in this world is run on oil, gas, and coal. And if America gets off it ... in ten years you will watch the greatest depression in the quickest period of time," Hannity told de Blasio, who responded by citing Germany's move to "renewables."
"Every economy in this world is run on oil, gas, and coal. And if America gets off it ... in ten years you will watch the greatest depression in the quickest period of time."
The New York City mayor also defended his call for energy-efficient skyscrapers as part of the city's Green New Deal, citing what he said was the buildings' impact on climate change.
"We cannot go on this way. We need a Green New Deal and one of the key things is to make sure buildings don't omit what they used to," de Blasio said.
In May, de Blasio faced a crowd of angry protesters during a rally to promote the city’s Green New Deal plan. The event was held inside the lobby of Trump Tower, where the Democrat threatened President Trump’s family company with millions of dollars in fines if its buildings don’t comply with new environmental standards.
Fox News' Andrew O'Reilly contributed to this report.