This Element examines how climate scientists have arrived at answers to three key questions about climate change: How much is earth's climate warming? What is causing this warming? What will climate be like in the future? Resources from philosophy of science are employed to analyse the methods that climate scientists use to address these questions and the inferences that they make from the evidence collected. Along the way, the analysis contributes to broader philosophical discussions of data modelling and measurement, robustness analysis, explanation, and model evaluation.