EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

Updated attribution of GSAT changes and implications

Aurélien Ribes1, Saïd Qasmi1, and Nathan Gillett2
Aurélien Ribes et al.
  • 1CNRM, Université de Toulouse, Météo France, CNRS, Toulouse, France (
  • 2CCCMA, Environment and Climate Change Canada, Victoria, BC, Canada

The observed increase of global air surface temperature (GSAT) has long been attributed to human activities. However, updating estimates of human-induced changes, and changes induced by specific subsets of forcings (e.g., green-house gases) remains of high interest to better understand recent changes and also produce refined projections.

Here, we use the newest climate model ensemble (CMIP6), improved observations, and a new statistical method to narrow uncertainty on the response to historical forcings. In addition, we focus on estimating the total warming since the pre-industrial (using 1850-1900 as a reference baseline), while most previous studies considered shorter periods.

Results suggest that most of the observed warming since the pre-industrial (+1.22°C +/-0.15°C in 2020) is human-induced (+1.15°C +/-0.15°C) and that a substantial fraction of GHG-induced warming (+1.54°C +/-0.33°C) has been offset by other anthropogenic factors (-0.39°C +/-0.28°C). We also quantify the contribution of specific forcings to the 2010-2019 warming rate, suggesting that the current rate of human-induced warming is +0.22°C/decade (+/-0.05°C/decade). We then derive implications of these findings in terms of future climate change, i.e., the response to a range of scenarios. Our results suggest that historical observations and historical climate change are already very informative about future changes and the property of the Earth System in general.

How to cite: Ribes, A., Qasmi, S., and Gillett, N.: Updated attribution of GSAT changes and implications, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-16112,, 2021.


Display file

Comments on the display

to access the discussion