The Fifth Assessment Report (AR5) by the United Nations’ Intergovernmental Panel on Climate Change (IPCC) is scheduled to be released in Stockholm on Friday.

But a draft of the report has been leaked to the media, and some climate scientists are already scoffing at its finding that “warming of the climate system is unequivocal,” and that “globally, CO2 is the strongest driver of climate change.”

Patrick Michaels, former climate professor at the University of Virginia and current director of the Cato Institute’s Center for the Study of Science, called the new report a “charade,” adding that it is already “obsolete.”