LAUSR

The combustion of fossil fuels is by far the largest human source of global greenhouse gas emissions, releasing more than 30 billion tonnes of carbon dioxide (CO2) into the atmosphere each year (IPCC 2014). Reducing fossil fuel combustion is thus a top priority for climate policy. For decades, national policymakers and international agreements have sought to achieve this goal through promoting energy efficiency, low-carbon technologies, carbon pricing, and other measures aimed at reducing the demand for fossil fuels. Focusing on the point of combustion makes intuitive sense, but efforts so far have yet to put fossil fuel use on a trajectory consistent with keeping global warming well below 2 °C and pursuing efforts to stay below 1.5 °C, as suggested by the Paris Agreement. Recognizing this shortcoming, policymakers, investors, researchers, and civil society actors have begun to look at the supply side of the fossil fuel economy—and the potential for supplyside measures to complement demand-side climate policies. A key insight driving these new approaches is that the political and economic interests and institutions that underpin fossil fuel production help to perpetuate fossil fuel use and even to increase it. From this emerging vantage point, continued investment in fossil fuel exploration, extraction, and delivery infrastructure makes global climate protection objectives much harder to achieve. The focus on fossil fuel supply in climate policy has high-profile proponents. OECD Secretary-General Ángel Gurría has emphasized the challenge posed by decades of investment in fossil fuel supply and the Bcarbon entanglement^ it creates, as governments depend on the profits they accrue (Gurría 2013). And during his final 18 months, US president Barack Obama took steps to begin constraining the expansion of fossil fuel production on climate Climatic Change (2018) 150:1–13 https://doi.org/10.1007/s10584-018-2266-3