A conversation with President Joe Biden’s climate czar, John Kerry took off when it turn to the use of private flights, a sore topic for jet-setting world leaders pushing the fight against global warming.

Ben Adler, senior climate editor at Yahoo News, broached the issue during an interview posted online on Friday, saying he read that Kerry “recently switched” from flying private to flying commercial.

“No, I didn’t fly private while I was in this job,” Kerry said, flatly rejecting the assertion. “It’s just a misnomer.”

Kerry, who became the nation’s first special presidential envoy for climate at the start of the Biden administration, said he has had “one, maybe two private flights, which were military flights in order to get to China during COVID.”

“We were forced into that,” he insisted before adding, “I fly commercially.”

Fox News reported last month that Kerry’s family sold their private jet, a Gulfstream GIV-SP, to a New York based-hedge fund after it made headlines for how many trips it took and its estimated hundreds of metric tons of carbon dioxide emissions since the start of the Biden administration.

Adler also pressed Kerry to respond to critics who say there is hypocrisy in world leaders at the forefront of the climate agenda who also fly private jets to major climate events in places such as Davos.

“I’ve talked to them about it,” he replied, in reference to his contemporaries. “They offset — they buy offsets, they offset, and they are working harder than most people I know to be able to try to effect this transition.”

The Republican National Committee, which shared clips of the interview on Twitter, highlighted these remarks as Kerry defending “global elites” who fly private while advocating for climate action.

Carbon offsets are “tradable ‘rights’ or certificates linked to activities that lower the amount of carbon dioxide (CO2) in the atmosphere,” according to the Massachusetts Institute of Technology’s Climate Portal website. “By buying these certificates, a person or group can fund projects that fight climate change, instead of taking actions to lower their own carbon emissions. In this way, the certificates ‘offset’ the buyer’s CO2 emissions with an equal amount of CO2 reductions somewhere else.”

Kerry further argued that even as there is a push for climate-friendly changes, including the toward the increased use of what the Energy Department describes as low-carbon sustainable aviation fuels, people should be “thoughtful” about how impractical it would be to suddenly wipe out every aircraft in the world that relies on fossil fuels.

Kerry, the Democrats’ failed 2004 presidential nominee, previously served as U.S. senator and as secretary of state under former President Barack Obama. Kerry helped negotiate the Paris climate agreement and in 2019, when he faced criticism for his use of a private jet for a trip to Iceland to receive an award for climate leadership, defended himself by saying, “If you offset your carbon, it’s the only choice for somebody like me who is traveling the world to win this battle.”