Suppose that a government wants to reduce its economy’s dependence on coal and decides as a result to tax coal mining companies $1 per ton for every ton of coal that they mine. Assuming that coal mining companies treat this tax as an increase in extraction costs this year, what effect will the tax have on current extraction in the model used in Figure 15.7? Now, think one step ahead. Suppose that the tax will be in place forever, so that it will also affect extraction costs in the future. Will the tax increase or decrease user cost? Does this effect increase or decrease the change in current extraction caused by the shift of the EC curve? Given your finding, should environmental taxes be temporary?