However, the system could soon be expanded if the US and others follow Europe with a cap-and-trade scheme, turning the current $90bn (£54bn) market into a $3.1 trillion one over the next decade. The idea has met with the support of a large number of major energy companies, such as BP and Shell. But Friends of the Earth wants carbon trading to be replaced by direct taxation and regulation of emissions production, arguing that the current system only enriches traders and does not drive carbon reductions.