Abstract:   In this lecture I will first review the different lines of evidence that have lead the scientific community to conclude the "Global warming is unequivocal". Within this context I will also comment on some misinterpretations of the data that are sometimes reported, for example in the press. I will then focus on the topic of attribution of the observed warming trend to the increase of greenhouse gas concentrations of anthropogenic origin, and how climate models play a crucial role within this context. Finally, I will review the concept of future climate prediction (or projection) and the different sources of uncertainty underlying climate projections, including a discussion of the topic of uncertainty characterization within the context of the climate change debate.