Global warming: which scenario are we heading towards?

The reality of global warming is now unanimous among the scientific community, but its evolution is still subject to uncertainties. Are we heading for a temperature rise of +1.5, +3 or +5°C by the end of the century? Discover the different possible scenarios.

Currently, the global temperature rise linked to greenhouse gas emissions amounts to +1.2°C compared to pre-industrial levels (1850-1900). In an attempt to predict the future climate, the Intergovernmental Panel on Climate Change (IPCC) has developed five different scenarios. In sound 6e reporthe defines a climate scenario as “ a plausible and often simplified representation of the future climate, based on a consistent set of climatological relationships”.

Up to 5°C warmer by 2100 for the most pessimistic scenario

The last five scenarios of the IPCC date from 2021 and include a scenario of greenhouse gas emissions in sharp decline, respecting the Paris Agreement, intermediate scenarios, and extreme scenarios without any regulation of our emissions. These scenarios give rise to general estimates of global temperature rise:

  • by 2040, depending on the different scenarios, the increase will be between +1.5°C for the most optimistic scenario to +1.6°C for the most pessimistic — or even +1.9°C in the estimate the most extreme;
  • between 2041 and 2060: between +1.6°C for the most optimistic and +2.4°C for the most pessimistic — or even +3°C in the most extreme estimate;
  • between 2081 and 2100: between +1.4°C for the most optimistic and +4.4°C for the most pessimistic — or even +5.7°C in the most extreme estimate.

However, the acceleration of global warming seems to exceed these estimates: the current short-term trend probably directs us to a warming of +1.5°C by 2026 according to the UN.

In France, +3.8°C by 2100 according to an intermediate scenario

This is a global average, on a world scale, but the warming scenarios for France have recently been updated. Our country is currently at +1.7°C and the CNRS specifies that ” in the intermediate scenario, France in 2100 could be 3.8°C warmer than that at the start of the 20th centurye century. Summers could be on average 5°C warmer compared to the decades 1900-1930”. But in an extreme scenario, France could warm up by 6.8°C by 2100.

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