A tax to keep cool

HERE is a hunch. Within the next half-century the governments of many industrial countries will raise perhaps one-fifth of their revenues from taxes and charges on pollution. Largest of all will be a tax on the carbon dioxide emitted when fossil fuels—coal, gas and oil—are burnt. The effect of this tax may be roughly to double the price of high-carbon fuels. Why should this happen? Because the alternative will be further concentration of carbon in the earth's atmosphere, with unpredictable but almost certainly nasty effects.