Industrial Civilization doesn't evolve. Rather, it rapidly consumes "the necessary physical prerequisites" for its own existence. It's short-term, unsustainable. "This is a one shot affair.... there will be one chance, and one chance only."

Energy-use per person is used as a measurable index of industrialization. In 1989, I proposed the Olduvai theory of Industrial Civilization, as illustrated in Figure 1.

Industrial Civilization can be described by a single pulse waveform of duration X, as measured by average energy-use per person per year.
The life-expectancy of Industrial Civilization is less than one-hundred (100) years: i.e., X < 100 years.
In 1989 I postulated that per capita energy-use had peaked and was already on the decline. But back then I lacked sufficient data to test the theory.

By 1996, however, I had successfully tested the Olduvai theory against numerous sets of data. Four of these tests are graphed in Figure 2. The following facts emerge.

On the average, world per capita energy-use reached a maximum value (i.e., a peak) in 1977.
The 1977-1995 rate of decline has averaged 0.90% per year.
Per capita energy-use will continue to decline as long as the world population growth rate exceeds the energy growth rate.
If the decline continues (and extinction is avoided), human societies will bottom out at the subsistence level of energy-use.
The Olduvai theory explains the Figure 2 data, but the exponential-growth theory (of mainstream economics) and the steady-state theory both fail.

The Olduvai theory cannot be overthrown (i.e., scientifically rejected) by outrage or indignation. However, it can be overthrown by either, (1) demonstrating that the four sets of data in Figure 2 are in error, or (2) by gathering additional data over the next few decades and demonstrating that the Olduvai theory cannot explain that data. In any case, the data will be the final arbiter.

1. Pre Industrial Phase [c. 3 000 000 BC to 1765]

A - Tool making (c. 3 000 000 BC)
B - Fire used (c. 1 000 000 BC)
C - Noelithic agricultural revolution (c. 8 000 BC)
D - Watts steam engine of 1765 Industrial Phase (1930-2025)
2. Industrial Phase [1930 to 2025, estimated ]

E - Per capita energy-use 37% of peak value
F - Peak energy-use
G - Present energy-use
H - Per capita energy-use 37% of peak value
3. Post Industrial Phase [c. 2100 and beyond ]

J, K, and L = Recurring future attempts at industrialization fail.
Other scenarios are possible.
[Note 5: In Figure 1, it may be helpful to think of the curve as income per person per year in dollars. Or perhaps as material standard of living. Better yet, just remember the little cartoon folks.]

Figure 1 divides the very long span of human history into three phases: (1) PreIndustrial, (2) Industrial, and (3)Post-Industrial. Seven events are marked on the left part of the curve (i.e., points A through G). Likewise, five hypothetical events are marked on the future part of the curve (i.e., H through L).

Phase 1, the Pre-Industrial Phase, spans thousands of millennia of sustainable conditions when society was powered exclusively by (renewable) solar energy. It began some three million years ago when our hominid ancestors started making simple tools (point A, Figure 1). The tools, in turn, made possible greater energy-use in such forms as food, fiber and shelter. Epic milestones leisurely passed, including the use of fire at about one million BCE and the Neolithic Agricultural Revolution at about 8,000 BCE. The end of the Pre-Industrial Phase is marked at 1765, the year James Watt invented the condensing steam engine (point D, Figure 1).

Phase 1 was followed by a transition period—i.e., The Industrial Revolution— delimited by the years 1765 and 1930 (points D and E, Figure 1).

Phase 2, the Industrial Phase, comprises the shaded portion of Figure 1. The life expectancy of Industrial Civilization is defined as the duration in years (x) between the leading and lagging "37% points" (i.e., points E and H). It is a short, extravagant period when transportation, commerce and industry were powered predominantly by (nonrenewable) fossil-fuels. Historic data (presented later) quantifies the peak period of the curve: i.e., the years between points E and G. Using that data, I mark the beginning of the Industrial Phase at 1930 (point E), the year average energy-use per person reached 37% of its peak value.

Note that the peak of Industrial Civilization was reached in about 1977 (point F), less than fifty years after it began. More significant, Figure 1 identifies the global energy "watershed". For the first time in the gaping millennia of human existence, average per capita energy-use peaked and began to decline!

As I read it, the descent into the Olduvai valley will be steep and swift. A scenario of Phase 3, the Post-Industrial Phase, is sketched in Figure 1 (i.e., from point I onward) wherein Industrial Civilization has disintegrated into farming villages, kinship tribes and rogue bands. The surviving population will have "achieved" permanent sustainability—at the subsistence level.

Of course, other scenarios are possible. For example, "The human species may follow the road to extinction rather than revert to the berry-picking stage" (Georgescu-Roegen, 1971). Or more recently, "The danger of extinction is real ... It is time to face the facts" (Leslie, 1996). However, because the circumstances of human society beyond the end of the second phase (i.e., point H. Figure 1) don't effect my thesis, the third phase is de-emphasized in the remainder of this discussion.