Back in the 1970s, it was popular to believe that oil company manipulations were behind the rises in the price of oil. I remember a fellow I played golf with when I was 14 explaining that there was a flotilla of oil tankers lurking beyond San Clemente Island, just waiting for the price to hit $14 per barrel. You heard that kind of thing all the time.
No, just kidding! Nobody believes in conspiracies anymore. Not even when there is a 48-year-old international oil conspiracy that has its own website.
Nobody has ever tried to drive up the price of a natural resource. (Well, except for the Hunt Brothers cornering the silver market in 1979-1980. And Jay Gould cornering the gold market in 1869. And, of course, as commenters point out, DeBeers and diamonds.) Nobody has ever used an environmentalist theory to drive up prices. (Well, except for the media panic in the 1990s over how America was about to run out of places to dump trash, which never made any sense -- if there's one thing America isn't in danger of running out of, it's holes in the ground. The frenzy turned out to be a hoax engineered by the PR department of Waste Management Inc. to get higher dumping rates from municipalities.) So, just forget about it!
Seriously, I don't know anything about the oil market. I'm just saying that an era when nobody wants to believe in conspiracies would be the best time to try one.