Trump's buildings don’t meet New York's new environmental regulations. The Trump Organization might have to pay a heavy price.

President Trump has long mocked the idea of climate change, but his refusal to take it seriously might cost him.

Eight of the Trump Organization's largest properties — including the renowned Trump International Hotel & Tower — in New York do not comply with the city's new greenhouse gas emissions-slashing regulations, The Guardian reports. That means the company would have to pay $2.1 million in fines every year from 2030, unless it revamps the buildings to make them more environmentally friendly.

New York passed new climate legislation in April, requiring all businesses larger than 25,000 feet to cut emissions by 40 percent or face annual fines. New York City Mayor Bill de Blasio hasn't signed the bill yet, though he plans to. Trump's buildings are far from the only culprits in the city, but they are certainly the most attention-grabbing.

de Blasio even hosted a rally on Monday inside of Trump Tower to directly challenge the president. Trump's supporters crashed the party.

"President Trump, you're on notice," de Blasio said. "Your polluting buildings are part of the problem. Cut your emissions or pay the price."

The Trump Organization does have time to get in line with the new rules, but it'll reportedly take quite a bit of work, including improving insulation, upgrading window glass, and replacing boilers.