Earth’s future climate trajectory is in the hands of human activity. Since the industrial revolution, anthropogenic greenhouse gases and aerosols emissions and land use have affected Earth’s energetic and the interplay between the energy, the water and the carbon cycles. The combination of observations and simulations lead to the conclusion that human influence has been the dominant cause of the observed warming since the mid-20th century. Climate simulations have become critical tools to understand the impact of human activity on climate, and to study the multiple interactions between atmosphere, land and ocean and the way they set up climate characteristics and variability at global and regional scales. This seminar will present the recent evolution of these models and the way they are used to answer different questions that become more and more precise regarding future climate, and that require being able to disentangle natural and anthropogenic causes. These questions concern mean climate change as well as different spatio-temporal scales of climate variability, extremes or different impacts on ecosystems and society. I will also discuss how the results of these simulations contribute to the international IPCC assessments on climate change or produce the basic information needed for numerous multidisciplinary questions on mitigation and adaptation.
