This subject investigates how organisms respond to variation in climate and what can be done to reduce their vulnerability to anthropogenic climate change. The subject makes use of a novel conceptual framework that defines 'vulnerability' as a function of the 'exposure' and 'sensitivity' of organisms to climate change. Therefore, we will begin by exploring how organisms are exposed to climate change, from regional climatic changes acting at the scale of populations, to local climatological effects acting at the scale of individuals. Next, we will examine what determines the sensitivity of organisms, focusing on the physiological, behavioural, and life-history traits that affect the ability of organisms to cope with and adapt to climate change. Then, we will show how exposure and sensitivity combine to determine the vulnerability of organisms, including in both managed and natural ecosystems. Finally, we will discuss the 'mitigation' and 'adaptation' strategies that can prevent the worst of the potential impacts from becoming realised and help protect our biodiversity in the face of anthropogenic climate change.