The main objective of the Paris agreement consists in 《 holding the increase in the global average temperature to well below 2°C above pre-industrial levels and pursuing efforts to limit the temperature increase to 1.5°C above pre-industrial levels, recognizing that this would significantly reduce the risks and impacts of climate change》. Still, if nothing is done to manage the increase of the greenhouse effect tied to human activity, we should see, at the end of this century, a minimum average 4°C global warming which will increase well beyond 2100. The impacts of such a 《 business as usual 》 scenario would be difficult if not impossible to handle. And, even if easier to manage, these difficulties will hold true for a +3 °C climate change a level which could be reached in the current context of the Paris agreement.