Countries around the world provide consumers with fossil fuel subsidies (Coady et al., 2016). In 2015, the subsidies reached $5.3 trillion (6.5% of global gross domestic product). Davis (2016) estimated that subsidies cause $4 billion in external costs annually. In a figure, show the effect of these subsidies and compare the post-subsidy equilibrium to the pre-subsidy equilibrium and to the social optimum, which accounts for pollution harms.