A counter scrolls in the new weather reports from France Télévisions. Franceinfo explains what it represents and how to interpret it.
You see it regularly in the “meteo climate” newspaper. A counter of +1.18…°C scrolls during these new weather reports from France Télévisions. Designed by researchers Aurélien Ribes (Météo France) and Christophe Cassou (CNRS), it materializes the evolution of global warming due to human activities since the pre-industrial period. Franceinfo explains to you what it represents exactly.
It shows the continuing pace of human-influenced global warming
This meter is an estimate of global warming caused by human activities since the pre-industrial period (1850). The pace of its progress is calculated according to the conclusions of the IPCC: the global temperature is rising by around 2 tenths of a degree per decade. Thus, it displayed +1.173°C on July 1, 2022. On July 1, 2023, it will therefore display +1.194°C (i.e. approximately 2 hundredths more). If it should not be read as the exact increase in the temperature of the globe at an instant T, the counter that you find below makes it possible to visualize the rate of warming of human origin: the latter worsens in a continues, on a daily basis.
Estimated global warming induced by human activities:
compared to the pre-industrial era
This figure will be updated each year by integrating the latest global average temperature observations. The warmer the planet, the faster the pace.
It illustrates that human influence is causing global warming
This counter only takes into account the human influence on the evolution of the global temperature. Several elements contribute to it. Firstly, greenhouse gas emissions, mainly due to the extraction and combustion of fossil fuels (coal, oil, gas), deforestation or even agricultural and industrial practices, warm the climate. . Secondly, aerosol emissions (particles in suspension, particularly from combustion) in the atmosphere, by reflecting the sun’s rays, slightly cool it. It is the sum of these two effects that the researchers took into account.
This calculation therefore does not include natural factors, which also influence the climate: solar activity and volcanism, as well as spontaneous fluctuations in the climate system, such as El Niño. The assessment of the contribution of these factors shows that they play a limited role in warming. “Almost all of the warming observed since 1850 is due to human activities”insists Aurélien Ribes, climatologist at Météo France.
>> Find the answers to your questions about global warming
When we look at the evolution over time of this indicator, the curve of total warming and that of warming due solely to man “almost overlap”, notes the researcher. Translation: the more greenhouse gases were emitted, the more the global temperature rose, and natural influences played only a very small role in this rise.
The two curves began their ascent from the end of the 19th century, accelerating in the 1950s during the post-war boom. Greenhouse gas emissions then progressed at a very rapid pace, but their warming effect was partly masked by the cooling effect of aerosol emissions, also rising sharply, and volcanic activities, preventing the temperature does not panic. After 1980, thanks to the fight against air pollution, aerosol emissions stabilized on a planetary scale, accelerating the global rise in temperatures.
It should not be read as the current temperature
The researchers repeat: “This number should not be interpreted as the average planetary temperature at any given time.” There is also considerable uncertainty in the estimate of human-caused warming: between +1.04°C and +1.35°C for 2023 compared to 1850. The use of a figure up to the eight decimal therefore only illustrates the current rate of warming attributable to human influence, without being representative of the actual accuracy of the day-to-day calculation.
It is possible to slow down the counter
Without rapid action, the meter could cross the +3°C mark by the end of the century, the IPCC warns us in its latest report. However, it can still slow down. If greenhouse gas emissions are massively reduced in the coming years, if ambitious measures are put in place immediately, temperatures can stabilize very quickly, and even drop from the middle of the 21st century. A scenario that would require upheavals in our societies: energy transition, thermal renovation of buildings, decarbonization of transport, change in our lifestyles…