This paper draws lessons from long run trends in energy markets for energy and climate policy. An important lesson is that consumer responses to energy markets1 The income elasticity of demand for an energy service indicates the percentage change in the consumption of the energy service for a one percent change in income. For example, an income elasticity of 0.5 (or 1.5) implies that, if income rises by 10%, consumption will increase by 5% (or 15%, respectively). Similarly, the price elasticity indicates the percentage change in the consumption of the energy service for a one percent change in the price of the energy service. That is, a price elasticity of -0.5 (or -1.5) implies that, if prices rise by 10%, consumption will fall by 5% (or 15%, respectively).2