Nearly 200 countries agreed in 2015 to put an end to temperatures not exceeding 2 ° C above pre-industrial levels, a threshold that is believed to be a watershed for the climate.
But the research said it was unclear whether the global climate could "settle" securely near a level more than two degrees above pre-industrial levels or whether it could trigger other processes that could lead to a further rise in the planet's temperature If the world stopped releasing greenhouse gases.
The average temperature is now about 1 ° C above its pre-industrial level, rising by 0.17 degrees every 10 years.
Scientists said: A sudden change is likely to occur if the critical limit is passed.
The study said maximizing opportunities to avoid entry into this "greenhouse" situation requires more than just reducing greenhouse gas emissions.
For example, there is a need to improve forest management, agricultural management and soil management, and to conserve biodiversity and techniques that remove carbon dioxide from the atmosphere and store it underground.
Some experts said in their comments on the research: The uncontrolled warming of the Earth is still uncertain; but it is not excluded.