Oil prices hit by Iran supply, China slowdown but $10 a barrel unlikely, says IHS's Yergin

It's not just fundamentals; oil prices are being slammed by a severe erosion in market confidence caused by the fragile global environment, according to a top commentator on energy and geopolitics.

Dan Yergin, vice chairman of consultancy IHS, told CNBC that worries stemming from Iran to China were key to the oil price.

"It's not just supply and demand…this time, oil prices are also being hammered by geopolitical factors and being hammered by geo-economical factors," Yergin said.

One big question for the market is when Iran would come back into the market and how much oil it would produce once U.S. sanctions are lifted, he said.

"There's not been an accommodation possible in OPEC…Saudi Arabia and the Gulf countries are not going to cut back, to make room for Iran coming back into the market," Yergin told CNBC's Squawk Box on Wednesday. (by Huileng Tan, CNBC)