The study is one of several to address the "carbon budget", which - among other things - determines how much CO2 the planet can emit and still reach a given limit for global warming.
It indicates the 2015 target, perceived by some as tough, could be met with very stringent emissions cuts.
It used computer models that project climate behaviour into the future.
The aim of the Paris deal was "holding the increase in global average temperature to well below 2C above pre-industrial levels and pursuing efforts to limit temperature increase to 1.5C."
