Fundamental Research Division
The DRF at the CEA assemble approximately 6,000 scientists since January 2016.
Découvertes et avancées | Scientific result | Climate | Climatic models
The Earth receives the energy radiated by the Sun and heats up. By absorbing infrared radiation, greenhouse gases in the atmosphere enhance this effect and exert a positive "radiative forcing". On the other hand, some aerosols reflect a fraction of the Sun's radiation back into space, cooling the atmosphere via a negative radiative forcing. Greenhouse gases like carbon dioxide are long lived, which means that even if the emissions were stopped, their concentration and thus their radiative forcing will continue for decades to centuries.
Understanding how different countries and regions contribute to global radiative forcing is essential to effectively implement the Paris Agreement processes, based on "common but differentiated responsibilities."
Using a simplified Earth system climate model, an international collaboration including researchers from China, Austria, and France quantified the radiative forcing related to global greenhouse gas emissions and aerosols. They then separated the regional contributions of the emissions, taking into account all human activities since the beginning of the industrial period. Indeed, some of the long-lived greenhouse gases emitted in the last century, such as CO2, are still present in the atmosphere and continue to warm the climate.
In 2014, the top three contributors to climate change, all human activities combined, were:
According to the scientists' modeling, greenhouse gases dominate the contribution to global warming in developed countries, while for developing countries, short-lived climate disruptors such as aerosols and ozone play a significant role. "Sulfate aerosols help cool the climate, but at the cost of poor air quality," explains Yves Balkanski, a scientist at LSCE and co-author of the study. "The originality of this study is to be able to attribute the climate change caused by each country, taking into account the complex interactions between the various compounds emitted to pass from emissions to air concentrations," says Philippe Ciais, who initiated this study at LSCE with Thomas Gasser, now a researcher in Austria at the International Institute for Applied Systems Analysis.
The contributions of individual countries and regions to the global radiative forcing, PNAS
CEA is a French government-funded technological research organisation in four main areas: low-carbon energies, defense and security, information technologies and health technologies. A prominent player in the European Research Area, it is involved in setting up collaborative projects with many partners around the world.