In Figure 1, the parabolic technique for the projection of conventional world oil production over time has been modified to derive the parameters pertaining to a range of peaks chosen from 2010 to 2035. This covers the period when the actual peak output is expected to occur. The individual parabolas so obtained are used to estimate the production at each peak and the quantity of unproduced oil after 2004 consistent with its respective case. The published world oil reserves at the end of 2004 are then subtracted to obtain an estimate of the oil yet to be discovered.

Because of the widely held view that the published reserves may be overstated, a correction line involving 150 gigabarrels (GB) of oil is also plotted to represent a maximum adjustment since the overstatement is most likely in the 50 to 100 GB range. The actual quantity of world undiscovered oil resources is likely to fall between these two lines. The main purpose of such a graph is to test the consistency of the date of the peak with the prediction of both the production at that time and the associated quantity of undiscovered resources. From the figure it appears unlikely the peak could be as early as 2010 or later than 2025.

In Figure 2, historical data for the world per capita production of oil was plotted on a matrix of lines of constant value to illustrate the remarkable constancy of this ratio in recent years. For projections into the future, a single conservative population scenario is employed whose main characteristic is a peak of eight billion people in 2050. The per capita production at a range of peaks of world oil production occurring between 2010 to 2035 was then plotted to show that these values also fall on the same per capita line though there may be a tendency for this ratio to increase in the far out years. A parabolic projection of the decline from the individual peaks was also calculated to illustrate the rapid fall in per capita production to be expected after the respective peaks. The pronounced fall in per capita production results from a steady (though slowing) increase in population past the peak in oil output; this effect provides an indication of the difficulties to be expected in the economy at that time.