Hillary Clinton’s presidential campaign will go carbon neutral, a campaign aide said Tuesday in response to video from a Republican opposition research firm that showed the Democratic frontrunner boarding a private plane after outlining part of her climate change platform in Iowa.

“This campaign will be carbon neutral,” the aide said Tuesday morning. “We’ll be offsetting the carbon footprint of the campaign and that includes travel.”

The aide would not specify how the campaign would achieve carbon neutrality, but said the campaign would roll out specifics as they unveil the rest of their climate change plan in the coming weeks.