The current debates on global warming have proved to be successful in sharpening our understanding of anthropogenic environmental changes in our past, but less so in tracing the historical dimension of thoughts and theories of climate change. This paper examines the history of the growing awareness of environmental change in the second half of the nineteenth century. It will examine the connection between European Sahara expeditions, colonial development in North Africa, and emergent theories of climate change and desertification. Contrary to the modern concerns with atmospheric gases, the nineteenth-century debate revolved around deforestation, sunspots, and soil erosion, but it was fueled by anxieties of environmental decline and resource scarcity that at times seem eerily similar to our own apprehensions today. The debate was also connected to political and technological concerns, or the aspirations of correcting “nature’s wrongs.” Climate change theories did not remain in the academic realm for long, but soon found their way into large-scale engineering plans of environmental transformation, or man-made climate alteration. This paper explores how the encounter with the Sahara and the wish to transform it into an economically usable landscape fueled the debates on climate change and desiccation, which came to be one of the most hotly debated issues in the European scientific community of the late nineteenth century.