But the risks from shale gas can be managed. Properly concreted well-shafts do not leak; regurgitants can be collected and made safe; preventing gas venting and flaring would limit methane emissions to acceptable levels; and the risk of tremors, which commonly occur as a result of conventional oil-and-gas activities, can be contained by careful monitoring. The IEA estimates that such measures would add 7% to the cost of the average shale-gas well. That is a small price to pay for environmental protection and the health of a promising industry.
For as well as posing environmental risks, a gas boom would bring an important environmental benefit. Burning gas emits half as much carbon dioxide as coal; so where gas substitutes for coal, emissions will fall. America's emissions have fallen by 450m tonnes in the past five years, more than any other country's. Ironically, given its far greater effort to tackle climate change, the European Union has seen its emissions rise, partly because of an increase in coal-fired power generation in response to Europe's high gas price.
