Abstract
Summary Human‐induced changes in global stocks and flows of carbon are major drivers of global climate change. This article presents a comprehensive and systemic account of a nation's carbon budget, comprising socioeconomic as well as ecological carbon flows in a historic time series. The example of Austria 1830–2000, for which excellent databases facilitate a comprehensive assessment, suggests that changes in socioeconomic metabolism during the agrarian−industrial transition are intimately linked with changes in land use and natural carbon flows. In the preindustrial agrarian colonization of Austria (during the thousands of years before 1830), a huge amount of carbon was released due to the expansion of agricultural land. At the dawn of Austria's industrialization (1830–1880), this process was terminated, and carbon inflows and outflows of ecosystems were approximately balanced. With rising fossil fuel consumption, Austria's socioeconomic system added growing amounts of carbon to the atmosphere each year. At the same time, fossil‐fuel‐powered surges in the productivity of agro‐ecosystems facilitated the production of growing amounts of agricultural biomass on shrinking agricultural areas. This greatly enhanced ecological carbon flows and, together with decreasing pressures on forests, allowed ecosystems to recover from past depletion and absorb increasing amounts of carbon. The systematic interlinkage between the socioeconomic energy system and carbon flows in ecosystems, as documented in this study, underlines the need for comprehensive and consistent analyses of society−nature interaction to develop monitoring tools and support strategies aimed at a more sustainable future.