Now, this is one peak you've probably heard a lot about. But you may not know that it already happened--about four years ago, according to The New York Times
Production of conventional crude oil--the black liquid stuff that rigs pump out of the ground--probably topped out for good in 2006, at about 70 million barrels a day. Production from currently producing oil fields will drop sharply in coming decades, the [International Energy Agency's annual] report suggests.
Although oil may be past its peak, oil use is definitely not going anywhere anytime soon. The IEA is predicting that after a short dip, oil production will continue on a relatively steady plateau for at least another 25 years, as new oil fields are discovered and exploited. But energy demand is still rising, especially from China. Peak oil, in turn, could directly cause peak coal, says Ars Technica:
If oil prices remain high and governments make progress on their emissions goals, there's a possibility that the world has already hit peak oil, and that the next few years will see its use plateau for a while before dropping again. Using these same assumptions, the report also said that we could hit peak coal somewhere within the next 20 years.