Fossil-fuel producers say that it would be prohibitively expensive to reduce levels of carbon dioxide emitted by the use of fossil fuels enough to halt global warming  This claim is probably false  Several years ago, the chemical industry said that finding an economical alternative to the chlorofluorocarbons (CFCs) destroying the ozone layer would be impossible
Yet once the industry was forced, by international agreements, to find substitutes for CFCs, it managed to phase them out completely well before the mandated deadline, in many cases at a profit
In some countries, the amount of carbon dioxide emitted by the use of fossil fuels has already been reduced without prohibitive expense, but at some cost in convenience to the users of such fuels.