Climate change: what we know and what not

There is ample scientific knowledge about climate change which is assessed at a frequency of about once every seven years by large, international groups of scientists in the comprehensive reports of the Intergovernmental Panel on Climate Change (IPCC). This presentation attempts a short and digestible summary of the certainties and uncertainties existing about the physics of climate change. For my summary, I strongly rely on the contribution of IPCC’s working group 1 to the most recent IPCC assessment report that was published in 2021. To set the stage, I first present some basics about climate and climate modeling before summarizing the current state of knowledge and then providing a few personal conclusions.