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4.6 Role of human activities in current global warming

The section 3.2.1 shows how to demonstrate with SimClimat the role of human activities in the current global warming. Climate models participating in CMIP can be used for the same purpose (figure 18).

In the control experiment, climate models are subject to increasing atmospheric concentrations in greenhouse gases ($CO_{2}$, but also $CH_{4}$) observed over the past 150 years, as well as the observed variation in the concentration of aerosols emitted by volcanoes. The simulations reproduce well the observed warming as well as the inter-annual variability related to the volcanic eruptions (figure 18a).

In a second experiment, climate models are subject only to the observed variation in aerosol concentration, with atmospheric concentrations of greenhouse gases remaining constant. The models simulate a constant temperature. This proves that the warming observed for 150 years is indeed caused by the increase in greenhouse gases.



Camille RISI 2023-07-24