South Korea, one of the world's fastest growing polluters, said it would commit itself to one of three options earlier this month: either an 8% increase from 2005 levels by 2020; maintaining 2005 levels; or reducing 2005 levels by 4%.

"We're getting an ever increasing number of visits from South Korean executives, who want to know more about how mandatory caps might work and what the implications would be," says Patrick Birley, chief executive officer of London-based European Climate Exchange