Science and technology. Global warming in France looks worse than expected.

The average temperature of France today is 1.66 degrees higher than that of the period 1900-1930 (archives).


Climate change in France could be worse than expected, study says. Temperatures could increase in 2100 by 3.8 degrees Celsius on average compared to the beginning of the 20th century, if greenhouse gas emissions do not drop drastically.

“This represents an increase up to 50% higher than previous forecasts,” said one of the authors of the study Aurélien Ribes, climatologist at the National Center for Meteorological Research (CNRM).

In the worst-case scenario, where we continue to have massive use of fossil fuels (oil, gas, coal), average temperatures could rise by 6.7 degrees, warns the study published in early October in the journal “Earth Systems Dynamics”. In the best case, the temperature increase would be 2.3 degrees.

But, overall, “France would warm up more (about +20%) than the planetary average”, indicates Mr. Ribes, with an average increase of 0.36 degrees per decade. According to the UN, global warming could, if nothing is done, reach +2.7 degrees by the end of the century.

+1.8 degrees in 2023

To arrive at these data concerning France, researchers from the CNRS, the CNRM and the European Center for Research and Advanced Training in Scientific Computing (CERFACS) based themselves on data collected since 1899 by around thirty meteorological stations distributed in France. to calculate current and future warming, from different scenarios, from the most optimistic, where carbon neutrality is achieved in 2050 after major efforts at the international level, to the most pessimistic, where emissions continue to climb.

These data showed that the average temperature of present-day France was 1.66 degrees higher than the period 1900-1930, “almost all of which (1.63 degrees) are due solely to human activities”, underlines Mr. Ribes . “Each ton of CO2 counts insofar as global warming depends on the cumulative level of emissions”, he adds, adding that “for 2023, we would already reach +1.8 degrees”.

The latest report from UN climate experts (IPCC) showed that the planet has already gained an average of almost 1.2 degrees Celsius since the pre-industrial era due to greenhouse gases generated by these activities. human.

The rise of 3.8 degrees in 2100 in France is only an average, warn the researchers: certain regions, particularly around the Mediterranean arc or in the mountains, could experience even higher temperatures. “That would mean that we would have extreme phenomena (heat, drought, floods) much stronger than what we experienced in the summer of 2022, when the warming was only 4 degrees on average”, underlines Julien Boé, researcher in climatology at the CNRS.


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