IEA: U.S. shale oil growth underestimated

Shale oil's impact will have "huge implications" for global energy markets for many years, executive director at the International Energy Agency Fatih Birol said at the World Economic Forum in Davos, Switzerland.

"(If) anybody thinks we have seen the full impact of the shale revolution in the United States, then he or she is making a big mistake," CNBC cited Birol as saying.

"We will see huge implications of shale, both for oil and gas, for many years to come," he added.