Observing climate change and its effects

Global annual mean temperature change since 1850

Sources: IPCC, 1^st Working Group, 2021; Copernicus, 2025 (HadCRUT5 data)

The warming of the global average temperature of land surface air and ocean surface water is very clear and consistent with climate models that integrate the impact of human activities on the climate (natural phenomena alone leading to a relatively stable global temperature).

The deviation from the average of the pre-industrial reference period 1850-1900 is slight until the mid-1930s, after which it usually becomes slightly positive until around 1980. Since the early 1980s, warming has become markedly more pronounced, and each of the last four decades has successively been the warmest since 1850. Warming over the last decade (2015-2024) is 1.24°C compared to the pre-industrial era (Indicators of Global Climate Change, 2025).

In 2024, the global rise in average temperature reached 1.6°C compared with the pre-industrial era. The years 2015-2024, at the forefront of which is 2024, were the ten warmest years on record.

Global average sea level since 1999

Source: Copernicus, 2025

Average sea level has risen by 3.7 mm/year since 1999, leading to a total rise of 9.4 cm in twenty-five years. The rate of sea-level rise has accelerated in recent decades, reaching 4.2 mm/year over the period 2014-2024, compared with 2.9 mm/year over the period 1999-2009.

Around 60% of the rise in sea level since 1999 is due to the melting of glaciers and polar ice caps, and 30% to expansion caused by rising water temperatures. The remaining 10% is linked to changes in water storage on earth (soil moisture, surface and ground water).

Average annual temperature change in metropolitan France since 1900

Note: trends in mean annual temperature are shown as deviations from the 1961-1990 average (11.8°C).
Source : Météo-France, 2025

As on a global scale, trends in mean annual temperatures in metropolitan France show a clear warming trend since 1900. The rate of warming has varied, with a particularly marked increase since the 1980s. The warmest years since measurements began in 1900 are all after 2010: 2014 (13.8°C), 2018 (13.9°C), 2024 (13.9°C), 2020 (14.1°C), 2023 (14.4°C) and 2022 (14.5°C). In 2024, the average temperature was 2.1°C higher than the average for the 1961-1990 period.

The average temperature observed in metropolitan France over the period 2015-2024 corresponds to a warming of 2.2°C compared with the pre-industrial period.

Temperatures and precipitation in metropolitan France since 1960

Note: from 2000 onwards, years are colored orange.
Source : Météo-France, 2025

While 2024 is one of the five hottest years on record in France, it is also one of the ten rainiest years. After 2022 was the hottest and driest year on record, followed by 2023 with average rainfall, 2024 had a surplus of around 15% and was marked by episodes of intense precipitation.

Change in thickness of selected temperate glaciers in metropolitan France since 1950

*The water equivalent meter is the unit used to describe the mass of a glacier by the thickness of an equal mass having the density of water. A loss of one meter of water equivalent means that the mass of ice lost, if transformed into water, would reduce the thickness of the glacier by one meter.
Note: the reference year shown for the five glaciers is 2001 (thickness = 0).
Sources: Association Moraine and Institut des géosciences de l'environnement, 2025

The annual evolution of a temperate glacier (i.e. ice with a temperature of around 0°C) is the result of the antagonistic effects of winter snowfall and summer temperatures. The glaciers are the elements of the natural environment most sensitive to temperature variations.

The sharp loss of glacier mass recorded since 1982 is the result of a significant increase in summer ice melting, which has been accentuated since 2003. On average, the five glaciers observed have lost 36 meters of water equivalent since 2001.

Number of fires and area burnt in metropolitan France since 2006

Source : European Forest Fire Information System, 2025

More than 12,000 hectares of forest were reduced to ashes, and 156 fires were recorded in France in 2024. These fires resulted in CO₂ emissions estimated at 1 megaton. Between January and September 2025, more than 35,000 hectares have already been burnt by 247 fires.

In 2022, the European Union recorded a record level of burnt areas, with 785,000 hectares of forest going up in smoke, including more than 66,000 in France.

For several years now, forest fire-prone areas have been expanding towards the north and west of France. Brittany is no longer spared.

Changes in harvest start dates for a panel of French vineyards since 1970

Note: the harvest dates shown are ten-year averages: for example, for 2023, the average is 2014-2023.
Sources: Inter-Rhône, ENITA Bordeaux, INRA Colmar, Comité interprofessionnel du vin de Champagne, 2025

The advancement of harvest dates is correlated with temperature trends, in an almost linear fashion. An evolution leading to an earlier harvest date is therefore a clear marker of global warming and the reaction of vegetation.

On average, for the vineyards shown above, harvesting took place 23 days earlier in the last decade than in the 1970s.