The 2015 Paris agreement's ambitious goal of limiting global warming to 1.5C remains within reach, a study suggests.

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."

But scientists admit they were taken by surprise by the ambition of this aim in the agreement.

The results of the work with computer models have been published in Nature Geoscience. This type of work, which involves projecting the behaviour of the climate into the future, necessarily contains uncertainties.

But the study authors say: "Pursuing 'efforts to limit the temperature increase to 1.5C' is not chasing a geophysical impossibility".

Co-author Michael Grubb, from University College London, said: "This paper shows that the Paris goals are within reach, but clarifies what the commitment to 'pursue efforts to limit the temperature increase to 1.5C' really implies."

Those commitments would require strengthening the nationally determined contributions (NDCs) - the pledges to cut emissions contained in the Paris agreement.