Sometimes oil reserves go down

Alaska's Untapped Reserves lowered by 90%.

The U.S. Geological Survey says a revised estimate for the amount of conventional, undiscovered oil in the National Petroleum Reserve in Alaska is a fraction of a previous estimate.
The group estimates about 896 million barrels of such oil are in the reserve, about 90 percent less than a 2002 estimate of 10.6 billion barrels.

The new estimate is mainly due to the incorporation of new data from recent exploration drilling revealing gas occurrence rather than oil in much of the area, the geological survey said.

OPEC reserves were revised upwards through out the 1980's not because more oil was found but because the allotment system which dictates how much each member can pump is based on official reserves.  If you increase your reserves, you can pump more.  Once one member country starts increasing their stated reserves, then so must everyone else if they are to continue to pump just as much oil as before.

Each OPEC nation is on its honor regarding their reserve number, they do not have to show the science to anyone, and they didn't.

The net effect is that those of us who attempt to follow the news but can not be an expert on everything became accustomed to hearing about the reserve numbers going up, and always going up.  We hear about a new find in Brazil or Canada and the number sounds large so we assume that it is a significant find.  The talking heads are not very good at giving us context and we are acculturated to trusting them.  They would not report it, we intuit, unless it were important.

But when science is used, sometimes reserve numbers go down.  And, since the 1970's those "large finds" are a pittance when we consider the rate at which those large finds will ever produce compared to a) the rate of (growing) world consumption and b) the impact of a 5% depletion rate on most of the world's largest and longest producing oil fields.

Yes, I tell my optimistic friends, we do not know the future and maybe human ingenuity will pull our collective dairy airs out of the fire, but only the most desperate of people depend upon such magical thinking when there is no sign of it yet.  We must also be prepared, I add, for being surprised to the down side.  Mother Nature is a capricious old woman and she is just as likely to throw gas on the fire as try to pull us out.