In 2014, the presenter of TF1 Évelyne Dhéliat presented a false weather bulletin with temperatures that France could know in 2050. 40 ° C in Besançon and Paris, 42 ° C in Lyon, 43 ° C in Nîmes … The goal was to make the French aware of global warming. As we know now, the projections have been sprayed and these temperatures seem less and less aberrant.
The forecasts say it: by the end of the century, France will experience warming at least 4 ° C. This climate change can cause serious consequences: floods, drought, fires, heat waves. It is therefore crucial for cities to anticipate it.
In Metz, to what consequences will the inhabitants face in 2050? Météo France provides the Climadiag tool free of charge, which allows you to see, city by city, what climatic projections provide for 2050 and 2100. In Lorraine, the main risks are floods and strong heat, major health issues public.
In Metz, it will be more than 2 ° C more in 2050
> 4 values are systematically presented: That for the reference period (1976-2005), the median value expected in 2050, the high value (the most alarmist scenario) of forecasts and low (the least alarmist). We have mainly compared with the median value.
The average annual temperature of the city of Metz will increase by more than 2.0 ° C by 2050 from the recent climate, this warming being more marked in summer than winter. According to the most likely scenario (the median value), in summer, it will make an average of 20.9 degrees against 18.5 currently.
The number of days of frost in very sharp decrease
In Metz, the annual number of frost days (day when the temperature drops below 0 ° C) will drop sharply in the future climate: while it freezes about 60 days a year currently, this figure will be almost divided by two in 2050.
Last year already, winter 2023-2024 only had 24 days of frost, an extremely low figure. The month of February 2024 had broken sweetness records in Metz and had known no day of frost (against a normal 14).
More rain in winter
In the spring, summer and winter, the accumulation of precipitation should be relatively little by 2050. On the other hand, in winter, the increase is strong: 40 millimeters of rain in addition in the season are to be expected.
Very hot days and hot nights more navel
In Lorraine, the very hot days (if the temperature exceeds 35 ° C during the day) and the hot nights (if the temperature during this night does not drop below 20 ° C) were rare in the recent climate.
-There are currently a single very hot day and two hot nights per year, on average. By 2050, this number of days should increase to 4 and the number of nights to 12.
This phenomenon can cause numerous and potentially fatal health risks, such as the heat stroke and dehydration.
The urban heat island: when cities suffocate
We have already noticed it when it is hot: we suffocate more in town than in the countryside. This phenomenon is called “Urban heat island” and Metz is already confronted with it, cSo many French cities.
This is a “Kind of hotter air dome covering the city” because of many factors: buildings blocking air circulation, significant automobile traffic, concrete that stores heat, air conditioning rejected in the street, etc. .
The phenomenon will only increase in the years to come if the cities do not adapt. In Metz, the municipality has understood this: every year since 2020, thousands of trees have been planted to combat urban heat and in school lessons, the macadam is removed.
By 2050, the dry climatic conditions will lead to an increase in the number of days with a significant risk of vegetation fire: in Metz, the number of days that this risk is present will go from 1 to 5 per year.
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