Across the Arctic, more than 100 wildfires are releasing clouds of carbon dioxide and other harmful emissions into the atmosphere.

The fires have been burning across the Arctic Circle in Siberia and Alaska for weeks. Though fire is a natural part of some Arctic ecosystems, scientists are calling the wildfires “unprecedented” for the month of June based on their size and carbon dioxide emissions.

“These are some of the biggest fires on the planet, with a few appearing to be larger than 100,000 hectares,” Thomas Smith, professor of geography at the London School of Economics, said in an email. “The amount of CO2 emitted from Arctic Circle fires in June 2019 is larger than all of the CO2 released from Arctic Circle fires in the same month from 2010 through to 2018 put together.”