Researchers at the Universities of Washington and California have warned that there is less than a 5% chance that global warming will be less than 2 °C above pre-industrial levels in the period to 2100.
In a letter published in Nature Climate Change, the researchers predict that the likely range of global temperature increase to 2100 is 2.0–4.9 °C, with median 3.2 °C.
The projection is based on their statistical analysis of data for 1960–2010, including the UN’s population projections for all countries.
Their findings, which take into account the effect of current mitigation policies, suggest that there is only a 1% chance that global warming will be limited to 1.5°C by 2100, the aspirational target of the Paris accord currently signed by 195 countries.
“Achieving the goal of less than 1.5 °C warming will require carbon intensity to decline much faster than in the recent past,” the study concludes.
Authors of the study are: Adrian E. Raftery and Peiran Liu of the Department of Statistics, University of Washington; Alec Zimmer of Upstart; Dargan M. W. Frierson of the Department of Atmospheric Sciences, University of Washington; and Richard Startz of the Department of Economics, University of California.