Katarzyna Tokarska, a researcher at the University of Victoria in British Columbia, Canada, led the new modeling in an effort to address a key question left unanswered by the Intergovernmental Panel on Climate Change (IPCC) in its consensus reports. The IPCC's worst-case scenario only charts warming up to two trillion metric tons of cumulative added carbon in 2100. In the new study, Tokarska and her colleagues asked what would happen if all known and recoverable fossil fuel resources were used.