GLOBAL PEAK ENERGY:
Implications for Future Human Populations
by Chris Clugston
WakeupAmerika.com
September 12, 2007

Energy is the “enabling” resource; most, if not all other natural and manmade resources and their capacities to sustain human life are derived from or dependent upon one or more sources of primary energy. The fact that the amount of energy available to human beings is subject to a limit—global peak energy—has profound implications for future human population levels and living standards.

Given humanity’s unquestioned dependence upon energy for survival, answers to the following questions are critical to our long term success as a species:

• When and at what level will global energy “peak”?
• What are the implications of global peak energy for the world’s human population?

Global peak energy will be delayed only in the event of:

• The discovery of one or more major new primary energy sources comparable in quantity, quality, and versatility to fossil fuels;
• Significant breakthroughs in the quantity, quality, and/or versatility associated with one or more existing primary energy sources; and/or
• Drastic and sustained reductions in the level of human energy consumption.

If this relationship holds, the maximum supportable worldwide human population at today’s average global living standard will decline from a peak ranging from 7.2 billion to 8.9 billion people, to between 2.0 billion and 5.0 billion people by the year 2100, and between 1.3 billion and 3.3 billion people by the year 2200.

The analysis contains the assumptions, projections, and findings that support these conclusions.

Contents

• Why This Study
• Historic Global Energy Consumption and Population Growth
• Current Global Energy Availability and Population Estimates
• Future Global Energy Availability Projections
• Implications of Global Peak Energy for Worldwide Population
• Conclusions
• Limitations
• Data Sources
• Author and Acknowledgements

Why This Study

Historic Global Energy Consumption and Population Growth

Data sources: US Census Bureau, HYDE database, EIA, Kremer (1993)

It is also clear that the significant improvements in material living standards realized by many of the earth’s human inhabitants over time are largely attributable to ever-increasing amounts of total available energy. Dramatic increases in both worldwide human population and living standards are especially evident during the past several hundred years, coincident with the availability of hydrocarbon-based primary energy sources (fossil fuels).

Current Global Energy Availability and Population Estimates

Data sources: EIA, IEA, US Census Bureau, HYDE database, various industry sources

Future Global Energy Availability Projections

Projections regarding the total amount of energy available globally between the year 2007 and the year 2200 are derived from the following assumptions regarding the amounts of energy to be produced from each currently known primary energy source. Two sets of assumptions were developed: a Conservative Scenario and an Optimistic Scenario.

Global Peak Energy

Applying the assumptions regarding future global energy availability to year 2007 global energy availability estimates yields the following global peak energy projections.

Source: Wake Up Amerika!

In the Conservative Scenario, “global peak energy”—the point at which the total amount of energy available to the worldwide human population from currently known primary energy sources reaches its maximum—occurs in the year 2025, at 574 quadrillion BTUs (Quads). In the Optimistic Scenario, global peak energy occurs only 5 years later in the year 2030, at 710 Quads.

In the Conservative Scenario the total amount of energy available globally declines to 158 Quads by the year 2100, and further declines to 101 Quads by the year 2200. In the Optimistic Scenario, the total amount of energy available globally declines to 397 Quads by the year 2100, and further declines to 261 Quads by the year 2200.

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Note that by calculating “total available energy” as the simple sum of the energy produced by each existing primary energy source, the analysis implies infinite substitutability among primary energy types—that is, every energy source is equally capable of producing energy for every energy-consuming application. Since this is obviously not the case (You can’t run millions of cars on wind or hydro…), the analysis may overstate the total amount of “useable” energy available at any given time, which may optimistically bias the projected timing and level of global peak energy. That is, global peak energy could occur sooner and at a lower level than the analysis indicates.

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Implications of Global Peak Energy for Worldwide Population

Worldwide peak population is determined by dividing the total amount of energy expected to be available during the global peak energy year by the average amount of energy expected to be consumed per capita during that year.

Source: Wake Up Amerika!

In the Conservative Scenario, the maximum supportable worldwide population at today’s average global living standard reaches a year 2025 peak of 7.2 billion people, who consume the projected 574 Quads of total energy available that year at today’s average annual rate of 80 million BTUs per capita.

Source: Wake Up Amerika!

In the Optimistic Scenario, the maximum supportable worldwide population at today’s average global living standard reaches a year 2030 peak of 8.9 billion people, who consume the projected 710 Quads of total energy available that year at today’s average annual rate of 80 million BTUs per capita.

The “Population versus Living Standard” Tradeoff

At any level of total available energy, the maximum supportable human population and the maximum attainable average human living standard are a “tradeoff”. That is, a higher average living standard necessitates a lower population level; a lower average living standard enables a higher population level.

The analysis examines the ranges of supportable worldwide population for the years 2007, 2100, and 2200, by considering three increasingly affluent “material” living standards, each of which is characterized by the annual per capita energy consumption level associated with its respective population:

1. Today’s Subsistence Living Standard: 20 million BTUs of per capita energy consumption annually, which is 25% of the 2007 global average, was about the average global per capita energy consumption level at the time of Christ, and is exemplified by the living standard associated with today’s residents of Zimbabwe, India, and Angola.
   
2. Today’s Average Global Living Standard: 80 million BTUs of per capita energy consumption annually, which is the 2007 global average and is exemplified by the living standard associated with today’s residents of Panama, Romania, and Serbia.
   
3. Today’s Average US Living Standard: 400 million BTUs of per capita energy consumption annually, which is 5 times the 2007 global average and is exemplified by the living standard associated with today’s American middle class.

Source: Wake Up Amerika!

In the Conservative Scenario, the maximum supportable worldwide population at today’s (2007) total available energy level of 532 Quads ranges from a theoretical high of 26.6 billion at today’s subsistence living standard, to 6.6 billion at today’s global average living standard, to 1.3 billion at America’s current average living standard.

By the year 2100, the maximum supportable worldwide population at the projected total available energy level of 158 Quads ranges from 7.9 billion at today’s subsistence living standard, to 2.0 billion at today’s global average living standard, to 400 million at America’s current average living standard.

By the year 2200, the maximum supportable worldwide population at the projected total available energy level of 101 Quads ranges from 5.0 billion at today’s subsistence living standard, to 1.3 billion at today’s global average living standard, to 300 million at America’s current average living standard.

Source: Wake Up Amerika!

In the Optimistic Scenario, the year 2007 “population versus living standard” tradeoff function is identical to the year 2007 Conservative Scenario function.

By the year 2100, the maximum supportable worldwide population at the projected total available energy level of 397 Quads ranges from a theoretical level of 19.9 billion at today’s subsistence living standard, to 5.0 billion at today’s global average living standard, to 1 billion at America’s current average living standard.

By the year 2200, the maximum supportable worldwide population at the projected total available energy level of 261 Quads ranges from a theoretical level of 13.0 billion at today’s subsistence living standard, to 3.3 billion at today’s global average living standard, to 700 million at America’s current average living standard.

Supportable Worldwide Population

If the post-peak average living standard were to be held constant at today’s global average, maximum supportable worldwide human population levels would decline continuously and irreversibly from the time of global peak energy until well past the year 2200. The analysis projects future maximum supportable worldwide population levels at today’s (2007) average global living standard—the living standard typical of existing populations in Panama, Romania, and Serbia.

Source: Wake Up Amerika!

In the Conservative Scenario, the maximum worldwide human population supportable at today’s global average living standard reaches a peak of 7.2 billion in the year 2025, declines to 2.0 billion by the year 2100, and declines further to 1.3 billion by the year 2200.

Source: Wake Up Amerika!

In the Optimistic Scenario, the maximum worldwide human population supportable at today’s global average living standard reaches a peak of 8.9 billion in 2030, declines to 5.0 billion by the year 2100, and declines further to 3.3 billion by the year 2200.

Conclusions

• If the energy availability assumptions outlined in the preceding analysis hold true, the total amount of energy available globally will continue to increase for the next 20-25 years, implying additional capacity for increasing human population during that time. At issue, however, is whether the “energy mix” going forward will support existing population levels, much less population growth; and whether other resources critical to human survival, such as water and food, will be available in sufficient quantities to support existing population levels, much less population growth. (Liebig’s Law of the Minimum)

• In the absence of 1) the discovery of one or more major new primary energy sources comparable in quantity, quality, and versatility to fossil fuels, 2) significant breakthroughs in the quantity, quality, and/or versatility associated with one or more existing primary energy sources, and/or 3) immediate and drastic reductions in the level of human energy consumption; global peak energy will probably occur between the years 2025 and 2030.
  
• While the amount of energy produced from energy sources such as the sun, wind, falling water, waves, tides, and the earth’s core is phenomenal, the percentage of such energy that is realistically accessible to human beings is very small, and is likely to remain so in the future due to low or negative returns, ROI and ERoEI, associated with attempting to harness such energy on a practical scale. Additional energy from these sources and from other “alternative” energy sources such as biofuels will certainly be produced in the future, but, barring one or more major breakthroughs, the total contribution from all existing alternative energy sources combined will never come close to offsetting the declining energy production associated with fossil fuels.
  
• Maximum supportable worldwide population will also quite probably peak between the years 2025 and 2030.

• Following the occurrence of global peak energy and worldwide peak population, the total amount of energy available to human beings will decline continuously and irreversibly, as will some combination of worldwide human population and human living standards.
  
• Worldwide population and/or living standards will continue to decline as the total amount of energy available globally declines until “equilibrium” is achieved. Equilibrium will be achieved when total human energy consumption reaches a level that is consistent with global biocapacity; that is, when the total amount of energy consumed by human beings is derived entirely from renewable primary energy sources.
  
• To the extent that the decline in energy available from fossil fuels negatively impacts the amount of energy available from “alternative” energy sources, due to the loss of “fossil fuel subsidies”, the total amount of energy available globally and the maximum supportable worldwide population level could decline at rates exceeding those projected in the Conservative Scenario.
  
• The goal of achieving an “American standard of living” for all or even a majority of the world’s current population is preposterous. The “optimistic peak” worldwide human population supportable at America’s current average living standard is less than 1.8 billion. Ironically, the maximum worldwide human population supportable at America’s current average living standard by the year 2200, even in the Optimistic Scenario, is only 300 million—today’s US population.
  
• Humanity has never experienced a trip down the post-peak (decline) side of the Total Available Energy Curve—facing continuous and irreversible declines in the resource that serves as the basis for our very existence; we have only traveled up the pre-peak (growth) side. There has always been “more”, and an expectation of “more”—never “less”. The psychological implications associated with an “inverted expectation paradigm”, in which things always get worse instead of always getting better, are unprecedented.

Limitations

• The underlying data upon which the analysis is based is subject to uncertainty, and may be inaccurate. Publicly accessible information sources may be wrong, outdated, or incomplete; I undoubtedly missed the “best available” data in some instances; data sources vary, sometimes widely-errors and bias result from the specific data set selected; and some of the “best” data is not available to the general public. Input from additional sources will mitigate this limitation, but it can never be totally eliminated.
  
• The assumption of “infinite substitutability” among all energy types noted in the report probably serves to bias the results in an “optimistic” direction, by implying the existence of more “useable” energy than may actually be the case at any point in time. (Optimally, “total available energy” would consider the specific applications for which each primary energy type is suitable, and depict the actual “useable available energy total”. Such complexity was beyond the scope of this analysis, and would not, in any case, result in delaying the projected timing of global peak energy.)
  
• The analysis focuses specifically on the relationship between total available energy and supportable human population levels and living standards. Other factors, such as the availability of food, clean water, and breathable air also certainly impact supportable human population levels and living standards. Energy is considered exclusively in my analysis because the historic relationship between energy availability and human population levels and living standards is well documented-and because global peak energy appears to be imminent. The analytical focus is not meant to detract from the gravity associated with potential shortages associated with food, water, air, or any other resource critical to human survival.
  
• The analysis assumes implicitly that the historic “pre-peak” relationship between total available energy and supportable human population levels and material living standards will hold true in a “post-peak” environment. While this assumption cannot be tested until the occurrence of peak global energy, it is intuitively obvious that, while the specific “decline functions” associated with available energy, human population levels, or human living standards may not be known with certainty, supportable human population levels and/or material living standards will certainly decline in some manner and to some degree as a result of continuously declining energy availability.

Data Sources

My underlying assumptions and projections regarding future energy availability associated with each nonrenewable and renewable primary energy source represent a synthesis of the information obtained from the above mentioned sources. The specific projections associated with the two scenarios presented in the analysis, Conservative and Optimistic, are derived from assumption sets regarding future energy availability believed by me to be “conservative” and “optimistic”.

(Note that in the final version of the analysis, the Conservative Scenario will depict the global peak energy/population scenario that lies approximately one standard deviation to the “conservative side” of expected peak scenario; and the Optimistic Scenario will depict the global peak energy/population scenario that lies approximately one standard deviation to the “optimistic side” of expected peak scenario.)

Population Data Sources

• Pre-1700: I used Michael Kremer estimates; he was frequently quoted by “early population” sources. As the following source indicates, early population projections seem to be comparable, irrespective of source: http://econ161.berkeley.edu/TCEH/1998_Draft/World_GDP/Estimating_World_GDP.html
  
• 1700-2000: I used the HYDE Worldwide Population Database, which contained an array of historic worldwide population estimates (http://www.mnp.nl/hyde/bdf/population/); estimates varied relatively widely from source to source, so I adopted the HYDE “mid-range” from the following spreadsheet: http://www.mnp.nl/hyde/Images/pop_summary_tcm63-22929.xls
  
• Current: I used the US Census Bureau projection for estimated 2007 world population: http://www.census.gov/ipc/www/idb/worldpopinfo.html
  
• Cross-checking: I also cross-checked my “selected” historic population data against US Census Bureau data (http://www.census.gov/ipc/www/worldhis.html), and against Jay Hanson’s estimates (http://dieoff.org/); all were in the same ballpark.

Energy Data Sources

• Pre-1800: I obtained my early historic energy consumption data from a project document used by Western Oregon University: http://www.wou.edu/las/physci/GS361/electricity%20generation/HistoricalPerspectives.htm.
  Their data tracked well with spot check estimates on other websites
  
• Post-1800: I used a synthesis of HYDE data http://www.mnp.nl/hyde/Images/total_energy_cons_tcm63-23030.xls;
  EIA data http://www.eia.doe.gov/pub/international/iealf/table29.xls;
  and a diagram created by Deutsche Shell: http://www.spiegel.de/international/spiegel/0,1518,grossbild-685811-429968,00.html

2007 total global energy consumption estimates

I used the EIA 2007 International Energy Outlook as the basis for my estimates: http://www.eia.doe.gov/oiaf/ieo/excel/figure_11data.xls, 482 Quads for 2007.

I cross-referenced against similar IEA estimates, http://www.iea.org/textbase/nppdf/free/2006/key2006.pdf, which were close in most respects, with the exception of hydro and “traditional biomass”.

The primary reason for the biomass discrepancy is that the EIA considers only “marketable” energy in their data. Since much of the wood and waste used for cooking and heating globally is simply gathered and burned, it is never actually “marketed” and does not appear in EIA data. I therefore assumed that the EIA understates actual traditional biomass use.

Data from the IEA, the Shell diagram referenced above, and from the Bioenergy Feedstock Information Network http://bioenergy.ornl.gov/faqs/index.html suggested use of traditional biomass in excess of 50 Quads/year in 2004, so I increased the EIA 2007 estimate of 482 Quads to the 2007 Clugston estimate of 532 Quads.

(I never did determine the reason for the EIA/IEA discrepancy in hydro energy consumption. I used the EIA estimate because other sources that I spot checked pegged hydro energy consumption/availability to be on par with nuclear, as did the EIA.)

2007 energy consumption per primary energy source estimates

Again, I used EIA data from their 2007 International Energy Outlook as the basis for my projections. The EIA provides a comprehensive breakdown of estimated nonrenewable energy consumption by source; however, they present only an aggregated total for renewables energy source, as far as I was able to determine: http://www.eia.doe.gov/pub/international/iealf/table29.xls and http://www.eia.doe.gov/oiaf/ieo/excel/figure_32data.xls.

The EIA does provide detail on estimated US consumption of energy per renewable source http://www.eia.doe.gov/oiaf/aeo/excel/aeotab_17.xls, and Wikipedia offered a comprehensive article on worldwide energy consumption by primary source that drew upon sources including the IEA, DOE, BP, and various energy related industry associations: http://en.wikipedia.org/wiki/World_energy_resources_and_consumption.

Based upon data obtained from these sites and from “confirmation spot checks” to websites associated with renewable energy sources, I derived the 2007 Clugston estimates for energy availability per primary energy source.

Future total available energy projections

I used the near-term growth rates contained in the above referenced EIA documents as the basis for my projections regarding both nonrenewable and renewable primary energy sources. I spot checked against IEA growth projections, which were very similar: http://www.iea.org/textbase/nppdf/free/2006/key2006.pdf.

Longer term “pre-peak” growth rate projections (beyond 2030), “peak” projections, and “post-peak” decline rate projections associated with both the Conservative Scenario and Optimistic Scenario are simply syntheses of the scores of studies, reports, websites, and interviews that I have read and heard over the past year and a half.

(Note that energy derived from each nonrenewable primary energy source is assumed to peak at some point, and then decline thereafter. Energy derived from each renewable primary energy source is assumed to reach a “practical limit” [peak] at some point, and then to decline or plateau thereafter.)

Author and Acknowledgements

Prior to founding Wake Up Amerika! he spent over 30 years working with information technology sector companies in marketing, sales, finance, M&A, and general management—the last twenty as a corporate chief executive and management consultant.

He received an AB/Political Science, Magna Cum Laude and Phi Beta Kappa from Penn State University, and an MBA/Finance with High Distinction from Temple University in Philadelphia, PA.

Below is a partial list of authors and researchers that Chris Clugston would like to acknowledge as important influences in his work:

© 2007 Chris Clugston

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