“Climate” deserves to be a keyword in the vocabulary of culture and society. It is arguably one of the most linguistically complicated words — a historically shape-shifting noun — whose meaning has changed and is changing, perhaps faster than the climate itself. Its nature, history, and vicissitudes are key concepts organizing our ideas of the aerial environment and our relationship to it. Although climate can be depicted and modeled, it cannot be directly visualized or forecast. The relationships of climate to meteorology and meteorology to climate studies are also dynamic. This article reviews the changing nature of ideas about climate over an extended time period, with special focus on developments in dynamic meteorology and dynamic climatology in the period 1900-1960, and with an update for the twenty-first century based on the implications of chaos theory. It adds a temporal dimension to the science and philosophy of weather prediction and climate change and the ways we think about the interrelationships of weather and climate. It may be a truism for historians that anything that can be named had different meanings in different eras, but some philosophers, with notable exceptions, have overlooked this. When doing epistemology, it is important to think about the history of the objects under discussion and how the meaning of terms has changed. As Mike Hulme has written recently, “Like all powerful ideas, climate change can be deceptively simple to define and yet subject to a multiplicity of cultural meanings and technical interpretations.” It is important to clarify the historical context and to think about what we are thinking about when we use terms such as climate, climate change, meteorology, dynamics, and models.
