The study, in the journal Nature, also found the decline in oil and gas production required globally by 2050 - to stick to that tight carbon budget - means many regions face peak production now or during the next decade.

A carbon budget is the cumulative amount of CO2 that can be released in a period of time while keeping within a temperature threshold - in this case 1.5C.

Many fossil-fuel extraction projects already planned or in operation are likely to hurt the world's chances of meeting internationally agreed target limits on global warming set out by the 2015 Paris Agreement.

And this "bleak picture", the scientists say, "is very probably an underestimate of what is required".

The carbon budget determined by the modelling would give the world a 50% chance of limiting warming to 1.5C.

But the study says: "That does not consider uncertainties around, for example, climate-system feedbacks