How twentieth-century scientists used proxies to understand historic climates, shaping scientific analyses of the past and the future. Unlike our daily reckoning with the weather, our experience of climate must be mediated through methods that measure the ebb and flow of climate, such as computer models, instruments like thermometers, and organic and inorganic remains known as “proxies.” Climate by Proxy by Melissa Charenko explores how scientists read the record of past climates and how their readings have engendered particular understandings of climate. Charenko focuses on the twentieth century, a period when scientists in Europe and North America began to believe that climate had a dynamic history worth studying. Scientists in this period developed several techniques to infer past climate from fossil pollen, tree rings, pieces of vegetation, and other organic remains imprinted upon by former climates. Climate by Proxy examines how these techniques helped shape notions of climate itself.   Charenko also shows how these varied interpretations of climate played an outsized role in explanations of human history and destiny. Geologists, botanists, ecologists, and other scientists interested in climate over long timescales routinely discussed how climate influenced plants, animals, and, notably, people. By following the scientists who reconstructed climate using natural archives, Climate by Proxy demonstrates how material objects worked with scientists’ perceptions of human groups to compel, constrain, and reinforce their understandings of climate, history, and the future.