Introduction
During
the historically recent period of global industrialization, the level
of human population has been closely related to the amount of energy we
have used. Over the last forty years, the per capita energy consumption
has averaged about 1.5 tonnes of
oil equivalent (toe) per person per year. As industrialization has
progressed, the amount of per capita energy used has also increased,
rising from a global average of 1.2 toe per person in 1966 to 1.7 toe
per person in 2006. As the global energy supply tripled over that time,
the population has doubled.
Figure 1 shows the close relationship between global
energy consumption,
world GDP and global population and implies that an overall
increase in the energy supply has supported the increase in population.
Can we assume that there would be negative consequences for the human
population if our energy supplies should start to diminish? In this
paper I shall present my estimate of the world energy situation over
the next century, and tie that to a projection of the human population
from now to 2100.
Figure 1: World Energy, GDP and Population, 1965 to 2003
Methodology
The
analysis in this paper is supported by a model of trends in energy
production. The model is based on historical data of actual energy
production, connected to projections that are drawn from the thinking
of various expert energy analysts as well as my own interpretation of
future directions.
The
current global energy mix consists of oil (36%), natural gas (24%),
coal (28%), nuclear (6%), hydro (6%) and renewable energy such as wind
and solar (about 1%). Historical production in each category (except
for renewable energy) has been taken from the BP
Statistical Review of World Energy 2007. In order to permit
comparison between categories I use a standard measure called the tonne
of oil equivalent (toe). Using this measure, well-known conversion
factors permit the energy obtained from different sources to be easily
compared. While this approach doesn't take into account the varying
efficiencies of different sources like oil and hydroelectricity, it
does provide a well accepted standard for general comparison.
We
will first examine each of the energy categories separately, applying
the development parameters that seem most appropriate to each. For each
component I will define as clearly as possible the factors and
parameters I have considered in building its scenario. This will allow
you to decide for yourself whether my assumptions seem plausible. We
will then combine them into a single global energy projection.
Once
the energy picture has been established we will explore the effect the
projected changes in energy supply may have on the world population.
Once that baseline has been developed, we will incorporate the probable
effects of ongoing ecological damage to arrive at a final projection of
human numbers over the next century.
Notes
The
WEAP model was developed as a simple Excel spreadsheet. The timing of
significant energy-related events and rates of increase or decrease of
supply were chosen through careful study of the available literature.
In some cases different authors had diverging opinions on these
matters. To resolve those situations I have relied on my own analysis
and judgment. As a result the model has remained open to the influence
of my personal biases. I make no apology for this; such scenarios
always reflect the opinions of their authors, and it is best to be
clear about that from the start. Nevertheless, I have made deliberate
efforts throughout to be objective in my choices, to base my
projections on observed trends in the present and recent past, and to
refrain from wishful thinking at all times.
The
WEAP model presents a global aggregation of the effects of energy and
ecological factors on world population. Although there is some
discussion of regional or national differences (which would be expected
to have a profound impact on the course of events in those places), the
model does not directly incorporate such influences. While you may see
this lack of granularity as a shortcoming, the paper is intended to
give a higher level view. Its purpose is to establish a broad
conceptual framework within which such regional disparities may be
understood.
This
paper will not present any prescriptive measures. The analysis is
intended solely to clarify a "most likely" future
scenario, based
purely on the situation as it now exists and will probably unfold. You
will not find any specific suggestions for what we ought to do, or any
proposals based on the assumption that we can radically alter the
behaviour of people or institutions over the short term. While the
probability of such changes will increase if the global situation
shifts dramatically, such considerations would introduce a level of
uncertainty into the analysis that would make it conceptually
intractable. The same constraint holds true for new technologies. You
will not find any discussion of fusion or hydrogen power, for example.
The
Excel spreadsheet containing the data used to assemble the WEAP model
is available here.
Energy
Component Models
Oil
The
analysis of our oil supply starts from the recognition that it is
finite, non-renewable, and subject to effects which will result in a
declining production rate in the near future. This situation is
popularly known as Peak Oil. The key concept of Peak Oil is that after
we have extracted about half the total amount of oil in place the rate
of extraction will reach a peak and then begin an irreversible decline.
This
happens both for individual oil fields and for larger regions like
countries, but for different reasons. In individual oil fields this
phenomenon is caused by geological factors inherent to the structure of
the oil reservoir. At the national or global level it is caused by
logistical factors. When we start producing oil from a region, we
usually find and develop the biggest, most accessible oil fields first.
As they go into decline and we try to replace the lost production, the
available new fields tend to be smaller with lower production rates
that don't compensate for the decline of the large fields they are
replacing.
Oil
fields follow a size distribution consisting of a very few large fields
and a great many smaller ones. This distribution is illustrated by the
fact that 60% of the world's oil supply is extracted from only 1% of the
world's active oil fields. As one of these very large fields plays
out it can require the development of hundreds of small fields to
replace its production.
The
theory behind Peak Oil is widely available on the Internet, and some
introductory references are given here, here and here..
Timing
There
is much debate over when we should expect global oil production to peak
and what the subsequent rate of decline might be. While the rate of
decline is still hotly contested, the timing of the peak has become
less controversial. Recently a number of very well informed people have
declared that the peak has arrived. This brave band includes such
people as billionaire investor T.
Boone Pickens, energy investment banker Matthew Simmons
(author of the book "Twilight in the Desert" that
deconstructs the
state of the Saudi Arabian oil reserves), retired geologist Ken
Deffeyes (a colleague of Peak Oil legend M. King Hubbert) and Dr. Samsam Bakhtiari
(a former senior scientist with the National Iranian Oil Company).
My
position is in agreement with the luminaries mentioned above, that the
peak is happening as I write this (in late 2007). I have confirmed this
to my own satisfaction by examining the pattern of oil production and
oil prices over the last three years. I discovered in the process that
crude oil production peaked
in May 2005 and has shown no growth since then despite a doubling
in price and a dramatic surge in exploration activity.
Decline
Rate
The
post-peak decline rate is another question. The best guides we have are
the performances of oil fields and countries that are known to be
already in decline. Unfortunately, those decline rates vary all over
the map. The United States, for instance, has been in decline since 1971
and has lost two thirds of its capacity since then, for a decline rate
of about 3% per year. On the other hand, the North Sea basin is showing
an annual decline around
10%, and the giant Cantarell field in Mexico is losing production
at rates approaching 20%
per year.
In
order to create a realistic decline model for the world's oil, I have
chosen to follow the approach of Dr. Bakhtiari in his WOCAP
model. He assumes a gradually increasing decline rate over time,
starting off very gently and ramping up as the years go by. WOCAP has
proven to be fairly accurate so far, and I have adopted a variant of
it. The main difference is that my model is a little less aggressive.
Where WOCAP predicts that production will fall from 4000 million tonnes
of oil per year (Mtoe/yr) now to
2750 Mtoe/yr in 2020, my model doesn't reach that point until 2030. The
WEAP model increases from a decline rate of 1% per year in 2015 to a
constant rate of 5% per year after 2040. Even such a relatively
conservative decline model gives astonishing results over the course of
the century, as shown in Figure 2.
Figure 2: Global Oil Production, 1965 to 2100
The
Net Export Problem
Before
we leave the subject of oil, some comments about oil exports are in
order. The graph in Figure 2 shows the aggregate oil production for the
world. However, the world is not a uniform place of oil production and
consumption. Some countries are net exporters of oil, while some are
net importers who buy the exporters' oil on the international market.
In
most countries the demand for oil is constantly increasing. This
applies especially to oil exporting nations, where rising oil prices
have stimulated economic growth. This additional growth has in turn
resulted in a higher domestic demand for oil which is satisfied out of
their surplus before it is made available for export. While the
nation's oil production is increasing this does not pose much of a
problem. When the exporting nation's production peaks and begins to
decline however, something ominous happens: the amount of oil available
for export declines at a faster rate than the production decline. This
has become known as the "net oil export problem".
Consider
this example. Say an exporting country produces one million barrels per
day, and its citizens consume 500,000 barrels per day. This leaves
500,000 barrels for export. Then production declines by 5% per year.
After one year their production is 950,000 barrels per day. At the same
time, their economy is booming, resulting in an increased demand of 5%.
This leads to a consumption of 525,000 barrels per day. That leaves
only 425,000 barrels for export, for a 15% decline in exports. A graph
over a number of years demonstrates the consequences:
Figure 3: Net Export Example
At the
end of 8 years, although the country is still producing over 700,000
barrels per day its exports have dropped to zero. This pattern has
already been seen in Indonesia, the UK and the USA, each of whom was
once a major oil exporter but is now a net importer.
This
effect is already visible on the world oil market. Figure 4 shows a
graph of total world
exports over the last 5 years. An overlaid trend line (a second
order polynomial for those who are interested) shows the
pattern: an imminent, rapid drop in the world's net oil exports.
Figure 4: World Net Oil Exports 2002 to 2013
Such
changes in exports are very worrisome for importing nations. The USA,
for instance, imports about two thirds of its oil requirements. If the
oil export market should suddenly begin to dry up as Figure 4 suggests
it could, the US would be forced to make some very hard choices. These
could include accepting a drastic reduction in industrial activity, GDP
and lifestyle, abandoning the international oil market and enter into
long-term supply contracts with producing nations, or even military
action to secure foreign oil supplies (as may have already been
attempted in Iraq).
I am
indebted to the work of Jeffrey Brown and his Export
Land Model for these insights.
Natural
Gas
The
supply situation with natural gas is very similar to that of oil. This
makes sense because oil and gas come from the same biological source
and tend to be found in similar geological formations. Gas and oil
wells are drilled using very similar equipment. The differences between
them have everything to do with the fact that oil is a viscous liquid
while natural gas is, well, a gas.
While
oil and gas will both exhibit a production peak, the slope of the
post-peak decline for gas will be significantly steeper due to its
lower viscosity. To help understand why, imagine two identical
balloons, one filled with water and the other with air. If you set them
down and let go of their necks, the air-filled balloon will empty much
faster than the one filled with water. A gas reservoir works much the
same way. When it is pierced by the well, the gas flows out under its
own pressure. As the reservoir empties the flow can be kept relatively
constant until the gas is gone, then it will suddenly stop.
Gas
reservoirs show the same size distribution as oil reservoirs. As with
oil, we found and drilled the big ones first. The reservoirs that are
coming on-line now are getting progressively smaller, requiring a
larger number of wells to be drilled to recover the same volume of gas.
For example, the number of gas wells drilled in Canada between 1998 and
2004 went
up by 400% (from 4,000 wells in 1998 to 16,000 wells in 2004),
while the annual production stayed constant. All this means that the
natural gas supply will exhibit a similar bell-shaped curve to what we
saw for oil.
One
other difference between oil and gas is the nature of their global
export markets. Compared to oil, the gas market is quite small. This is
due to the difficulty in transporting a gas as opposed to a liquid.
While oil can be simply pumped into tankers and back out again, natural
gas must first be liquefied (which takes substantial energy),
transported in special tankers at low temperature and high pressure,
then re-gasified at the destination which requires yet more energy. As
a result most of the world's natural gas is shipped by pipeline. This
pretty well limits gas to national and continental markets. That has an
important implication: if a continent's gas supply runs low it is very
difficult to supplement it with gas from somewhere else that is still
well-supplied.
The
peak of world gas production may not occur until 2025, but two things
are sure: we will have even less warning than we had for Peak Oil, and
the subsequent decline rates may be shockingly high.
For the gas model I have chosen as the peak a plateau from 2025 to
2030. This is followed by a rapid increase in decline to 8% per year by
2050, remaining at a constant 8% per year for the following 50 years.
This gives the production curve shown in Figure 5.
Figure 5: Global Natural Gas Production, 1965 to 2100
Coal
Coal
is the ugly stepsister of fossil fuels. It has a terrible environmental
reputation, going back to its first widespread use in Britain in the
1700s. London's coal-fired "peasoup" fogs were
notorious, and damaged
the health of hundreds of thousands of people. Nowadays the concern is
less about soot and ash than about the carbon dioxide that results from
burning coal. Weight for weight, coal produces more CO2 than either oil
or gas. From an energy production standpoint coal has the advantage of
very great abundance. Of course this abundance is a huge negative when
considered from the perspective of global warming.
Most
coal today is used to generate electricity. As economies grow, so does
their demand for electricity, and if electricity is used to replace
some of the energy lost due to the decline of oil and natural gas, this
will put yet more upward pressure on the demand for coal. At the moment
China is installing two to three new coal-fired power plants per week,
and has plans to continue at this pace for at least the next decade.
Just
as we saw with oil and gas, coal will exhibit an energy peak and
decline. One factor in this is that we have in the past concentrated on
finding and using the highest grade of coal, anthracite. Much
of what
remains consists of lower grade bituminous and lignite. These grades of
coal produce less energy when burned, and require the mining of ever
more coal to get the same amount of energy.
The Energy
Watch Group has conducted an extensive analysis of coal use over
the next century, and I have adopted their "best case"
conclusions as a
starting point for this model. The model projects a continued rise in
the use of coal out to a peak in 2025. As global warming begins to have
serious effects there will be mounting pressure to reduce coal use,
resulting in a slightly more aggressive decline slope than the one
projected by the Energy Watch Group. Unfortunately, due to its
abundance and our need to replace some of the energy lost from the
depletion of oil and gas, the decline in coal use will not be as
dramatic as seen with those fossil fuels. The model has the annual
decline in coal use increasing evenly from 0% in 2025 to a steady 5%
annual decline in 2100. These assumptions give the curve shown in
Figure 6.
Figure 6: Global Coal Production, 1965 to 2100
Of
course this use of coal carries with it the threat of increased global
warming due to the continued production of CO2. Many hopeful words have
been written about the possibility of alleviating this worry by
implementing Carbon Capture and Storage. CCS usually involves the
capture and compression of CO2 from power plant exhaust, which is then
pumped into played-out gas fields for long term storage. This
technology is still in the experimental stage, and there is much
skepticism surrounding the security of storing such enormous quantities
of CO2 in porous rock strata. Such plans play little part in this
analysis, although later when we discuss the intersection of ecological
degradation with declining energy I will assume that little has been
done compared to the scale of global CO2 generation.
Nuclear
The graph
in Figure 7 is the result of a data synthesis and a bit of projection.
I started with a table of reactor ages from the IAEA (reprinted in a
presentation to the Association
for the Study of Peak Oil and Gas), the table of historical nuclear
power production numbers from the BP
Statistical Review of World Energy 200 and a table from the Uranium Information Centre
showing the number of reactors that are installed, under construction,
planned or proposed worldwide.
The interesting
thing about the table of reactor ages is that it shows that the vast
majority of them (361 out of 439 or 82% to be precise) are between 17
and 40 years old. The number of reactors at each age varies of course,
but the average number of reactors in each year is about 17. The number
actually goes over 30 in a couple of years.
Two realizations
form the basis for my model of nuclear power. The first is that since
reactors have a finite lifespan averaging around 40 years, a lot of the
world's reactors are rapidly approaching the end of their useful life.
The second is that the replacement rate inferred from the UIC planning
table is only about three to four reactors per year for at least the
next ten years, and probably the next twenty.
These two facts
mean that within the next twenty years we will have retired over 300
reactors, but will have built only 60. So by 2030 we will have seen a
net loss of 240 or more reactors: over half the present stock. Since
these reactors are all broadly similar in size (a bit less than 1 GW on
average) that means we can calculate the approximate world generating
capacity at any moment in time, with reasonable accuracy out to 2030 or
so.
The model takes
a generous interpretation of the available data. It assumes we will
build 3 GW of nuclear capacity per year for the next ten years (about
what is under construction now), 4.5 GW per year for the subsequent ten
years (these are the reactors in the planning stages that will probably
end up being built), and 6 GW/year for the 20 years following that from
the reactors that have been proposed. It assumes a rising construction
profile because I think we will start to get desperate for power in
about 20 years - this is the reason reactor completions double over
that period compared to today.
Figure 7: Global Nuclear Production, 1965 to 2100
The
drop in capacity between now and 2030 is the result of new construction
not keeping pace with the rapid decommissioning of large numbers of old
reactors. The rise after 2030 comes from my prediction that we will
double the pace of reactor construction in about 2025 when the energy
situation starts to become visibly desperate and we realize that most
of the reactors from the 1970-1990 building boom are out of service.
The final decline after 2060 comes from my expectation that we will
start losing global industrial capacity in a big way in a few decades
due to the decline in oil and natural gas. As a result, by 2060 we
won't have the capability we would need to replace all our aging
nuclear reactors.
The
argument for a peak in nuclear capacity in 2010 and the subsequent drop
is very similar to the logistical considerations behind Peak Oil - the
big pool of reactors is about to be exhausted, and we're not building
enough replacements. In fact, to stay even with the rate of
decommissioning of our current reactor base we would need to build 17
new reactors a year (more than 5 times the number that are now on the
books) forever. That seems very unlikely given the capital, regulatory
and public relations environments that the nuclear industry is now
operating in.
As an
aside, the drop in generating capacity after 2010 means that any
concerns about outstripping the supply of mined uranium (currently
about 50,000 tonnes per year worldwide) are avoided altogether.
Hydro
If
coal is the ugly stepsister, hydro is one of the fairy godmothers of
the energy story. Environmentally speaking it's relatively clean, if
perhaps not quite as clean as once thought. It has the ability to
supply large amounts of electricity quite consistently. The technology
is well understood, universally available and not too technically
demanding (at least compared to nuclear power). Dams and generators
last a long time.
It has
its share of problems, though they tend to be quite localized.
Destruction of habitat due to flooding, the release of CO2 and methane
from flooded vegetation, and the disruption of river flows are the
primary issues. In terms of further development the main obstacle is
that in many places the best hydro sites are already being used.
Nevertheless,
it is an attractive energy source. Development will probably continue
in the future at a similar pace as in the past, at least until loss of
technological capacity or demand makes further development moot.
In
order to project the growth rate of hydro power, I used a second order
polynomial curve fitted to the production history of the past 40 years.
Using such a projection assumes that future development will look very
much like the past, at least until an external influence alters the
course of events. The projection is shown in Figure 8. One thing that
gives confidence in the reliability of the projection is the high
correlation of the chosen curve to the actual data, as shown in the
R-squared value of .994 (the closer to 1.0 the better the fit).
Figure 8: Projected Hydro Production
The
model for hydro power shown in Figure 9 has capacity growing to about
double its current level by 2060. It then declines back to the current
level by 2100. The peak and subsequent decline in the second half of
the century is
attributed to the full occupancy
of virtually all high-value hydro sites, a general loss of
global industrial capacity and a
reduction in water flows due to global warming. These are the external
influences mentioned above.
Figure 9: Global Hydro Production, 1965 to 2100
Renewable Energy
Renewable
energy includes such sources as wind, photovoltaic and thermal solar,
tidal and wave power etc. Assessing their probable contribution to the
future energy mix is one of the more difficult balancing acts
encountered in the construction of this model. The whole renewable
energy industry is still in its infancy. At the moment, therefore, it
shows little impact but enormous promise. While the global contribution
is still minor (at the moment renewable technologies supply less than
1% of the world's total energy needs) its growth rate is exceptional.
Wind power, for example, has experienced annual growth rates of 30% over
the last decade.
Proponents
of renewable energy point to the enormous amount of research being
conducted and to the vast range of approaches being explored. They also
point out correctly that the incentive is enormous: the development of
renewable alternatives is crucial for the sustainability of human
civilization. All this awareness, work, and promise give the nascent
industry an aura of strength verging on invincibility. That in turn
supports a conviction among its promoters that all things are possible.
Of
course, the real world is full of unexpected constraints and
unwarranted optimism. One such constraint has shown up in the field of
biofuels, where a realization of the conflict between food and fuel has
recently broken through into public consciousness. One can also see
excessive optimism at work in the same field, where dreams of replacing
the world's gasoline with ethanol and biodiesel are now struggling
against the limits of low net energy in biological processes.
The
key questions in developing a believable model are, what is the
probable long-term growth rate of renewable energy going to be over the
next 50 years, and what amount of energy will it ultimately contribute?
While
I do not subscribe to the pessimistic notion that renewables will make
little significant contribution, it's equally unrealistic to expect
that they will achieve a dominant position in the energy marketplace.
This is primarily because of their late start relative to the imminent
decline of oil, gas and nuclear power, as well as their continued
economic disadvantage relative to coal.
In
order to project a realistic growth rate for renewable energy I have
used the same approach as with hydro above. Data on the global
production of renewable energy from 1980 to 2005, collected by the Energy
Information Agency , was used as the starting point for the
projection shown in Figure 10. As in the earlier use of this technique
for the projection of hydro production, the closeness of the fit (again
a second order polynomial giving an R-squared value of .994) gives a
high degree of confidence in
the projection.
Figure 10: Projected Renewable Production
This
technique has a couple of shortcomings. First, it aggregates all
renewable energy sources: geothermal, solar, wind, biomass
etc.
Because some of these sources are still in their infancy, it is
possible that they may exhibit higher growth rates in the future, thus
making the projection too conservative. Balancing this of course is the
possibility that they may run into unexpected constraints, skewing the
outcome in the other direction. The second problem is that due to the
youth of the industry large discontinuities in production from year to
year may render the curve fit unreliable. These objections have been
addressed by using only the most recent 15 years of data as the basis
for the projection. This encompasses the years of highest growth in the
wind and solar industries, and as we see from the high correlation of
the fit, the yearly variation from the curve is quite low. On balance,
the projection seems suitable as a basis for the model.
I
have placed the peak contribution in 2070. Production declines
following the peak because many renewable energy sources (e.g. wind
turbines and photovoltaic solar panels) are dependent on a high level
of technology and manufacturing capacity. Still, the model foresees
renewables contributing more to the energy picture at the end of the
century than any other source except for hydro.
Figure 11: Global Renewable Energy Production, 1965 to 2100
Putting the Energy Sources in Perspective
Figure 12: Energy Use by Source, 1965 to 2100
Figure
12 shows all the above curves on a single graph. This gives a sense of
the relative timing of the various production peaks, as well as showing
the contribution of each energy source relative to the others over time.
As
you can see, fossil fuels are by far the most important contributors to
the world's current energy mix, but all three are in rapid decline by
the second half of the century. Hydro and renewables are making
respectable contributions by mid-century, while nuclear power plays a
constant role. By the end of the century, oil and natural gas have
dropped out of the picture almost entirely, while the dominant players
are hydro, renewable sources , coal and nuclear power, in that order.
Figure 13: Total Energy Use, 1965 to 2100
Figure
13 has all the energy curves added together to show the overall shape
of total world energy consumption. This graph aggregates all the rises,
peaks and declines to give a sense of the complete energy picture out
to 2100. The graph shows a strong peak in about 2020, with a steepening
decline out to 2100. The main reason for the decline is the loss of
oil, gas, and (to a lesser extent) coal. The decline is cushioned by an
increase in hydro and renewables over the middle of the century, and
averages out to a little less than 3% per year.
Unfortunately,
the loss of the enormous contribution of fossil fuels means that the
total amount of energy available to humanity by the end of the century
may be less than one fifth of the amount we use now, and less than one
sixth the amount we will use at our energy peak a decade or so from
now. This shortfall contains an ominous message for our future. That
message is the subject of the remainder of this paper.
The
Effect of Energy Decline on Population
As I said
in the introduction, human population growth has been enabled by the
growth in our energy supply. It is now time to examine this
relationship a little more closely, and to think about the implications
of the global energy model we have just assembled.
The
Historical and Current Situation
According
to an analysis of historical human energy use published by Western
Oregon University, while per our capita food energy consumption has
remained relatively constant (within a range of 3:1 over most of human
history), the energy we each use for the rest of our activities has
grown almost thirty times from our early agricultural days to the
consumption we now see in developed countries. The world's population
has increased by a similar amount in that time, from 200 million in 1
CE to 6.6 billion today.
One of
the more significant results from the WOU study is the non-food energy
consumption of an "advanced agricultural man" from
northern Europe in
the 1400s. When that number of 20,000 kilo-calories per day is
converted to our standard measure of tonnes of oil equivalent, it turns
out to be 0.75 toe per year. The consumption of an "early
industrial
man" in 1875 was estimated to be 2.5 toe per year. For
comparison, the
global average per capita non-food energy consumption in 1965 was only
1.2 toe per year.
There
is of course a great disparity in global energy consumption. The
combined populations of China, India, Pakistan and Bangladesh (2.7
billion) today use an average of just 0.8 toe per person per year,
compared to the global average of 1.7 and the American consumption of
about 8.0.
It is
reasonable to expect that a declining world energy supply would affect
countries at opposite ends of the consumption spectrum quite
differently. The picture will be further complicated by the effects of
declining net oil exports on oil importing nations, and whether those
nations are rich or poor. While a rigorous analysis of these effects is
beyond the scope of this paper, we will look at some of the probable
short and medium term impacts. This will be in addition to our
examination of the overall effect of energy decline on global
population that is the main objective of the paper.
Long-Term
and Aggregate Effects
As
shown in the example of the "agricultural man" above,
human beings need
a significant amount of energy to sustain even a relatively poor
quality of life. This implies that as energy supplies decline and per
capita energy falls, the quality of life of those on the bottom end of
the consumption scale will be drastically affected. The degree of the
effect will depend on how close they are to a bare subsistence level of
consumption.
In our
civilization, scarce goods are allocated by price: the scarcer a
necessary good is, the higher its price will go. Those who can afford
to pay can acquire it at the expense of those who cannot. Those who are
out-bid have to reduce their consumption or even do without. This
applies as much to energy as an aggregate commodity
as it does to any
other good.
The
extent to which someone can survive a drop in energy supplies and the
resulting rise in energy prices depends primarily on whether they have
other consumption they can forego to allow them to pay for the energy
they need. Those at the bottom of the economic ladder have no ability
to reallocate their discretionary spending for this purpose, because
they have no discretionary spending. As a result, they will be out-bid
and will have to do without some amount of fuel or electricity. If
their consumption is already so low that it barely sustains them, such
an occurrence would obviously be catastrophic.
Over
4.5 billion of the world's 6.6 billion occupants live in countries that
have per capita energy consumptions under 2.0 toe per year. As energy
supplies decline, these countries are at risk of vast increases in
mortality as they are out-bid in the global energy marketplace and
their populations begin to fall below the minimum energy level required
for sustaining life.
Short
Term and Regional Effects
These
effects will result primarily from Peak Oil and the coming net export
crisis. As the effects of declining exports are felt, the market price
of oil will escalate very rapidly.
Some
oil producing countries will choose to sell much of their product on
the international market for the money it will bring. Such actions may
result in a deprived and discontented population, giving rise to fuel
riots and even the threat of revolution. Other producers may decide to
keep their oil at home to preferentially supply their own citizens'
needs. This will result in a wave of nationalization of oil resources
so that governments can direct its distribution and control the local
price.
Oil
importing nations will face a choice similar to the poor nations
described in the previous section. They will need to reallocate their
discretionary money toward the purchase of oil. If that cannot buy
enough to satisfy their needs they will be forced to reduce their
consumption. If they are unwilling to do either, and have the means
available, they may decide to secure their oil supply by force of arms.
Nearby producing nations that are keeping (or thought to be keeping)
their oil off the world market will be at special risk of becoming
targets in a resource war. Some aspects of this geopolitical energy
calculus may have already come into play in the American invasion of
Iraq.
The net oil export crisis may well be the defining geopolitical event of the next decade.
The Population Model
The
population model is based mainly on the long-term aggregate effects of
energy decline. The mechanisms of the population decline it projects
are not specified. However, it is likely that they will include such
things as major regional food shortages, a spread of diseases due to a
loss of urban medical and sanitation services and an increase in deaths
due to exposure to heat and cold.
The
main interaction in the model is between the energy available at any
point in time (shown in Figure 13) and an estimate of average global
per capita consumption. Current global consumption is about 1.7 toe per
person per year, and in the model that declines evenly to a consumption
of 1.0 toe per person per year by 2100. To put that in perspective, the
world average in 1965 was 1.2, so the model is not predicting a huge
decline below that level of consumption. An increase in the disparity
between rich and poor nations is also likely, but that effect is masked
by this approach.
Under
those assumptions, the world population would rise to about 7.5 billion
in 2025 before starting an inexorable decline to 1.8 billion by 2100.
Figure 14: World Population with Declining Energy, 1965 to 2100
Effects of Ecological Damage
In
order to complete the picture of human population over the next century
it is necessary to bring some ecological insights to bear.
According
to Wikipedia:
Ecology is the
scientific study of the distribution and abundance of living organisms
and how the distribution and abundance are affected by interactions
between the organisms and their environment.
There
are two ecological concepts that are the keys to understanding
humanity's situation on our planet today. The first is Carrying
Capacity, the second is Overshoot.
Carrying
Capacity
The
carrying capacity of an environment is established by the quantity of
resources available to the population that inhabits it. The usual
limiting resource is assumed to be the food supply. For plants and
animals this definition is easily applied. The fluctuations in
predator-prey relationships (e.g. wolves and deer or foxes and
rabbits), or the number of buffalo that can live on a given area of
prairie grassland are classic examples.
When
we try to apply this definition to human beings we run into problems.
In the animal world if a population is below the carrying capacity of
its environment it will expand, and when it reaches the carrying
capacity its numbers will stabilize. In the case of human beings,
however, our numbers have been growing for a very long time, and in
fact are still growing, though more slowly. Does this mean that we have
not yet reached the carrying capacity of the Earth, or are other
factors at work?
The missing consideration is, of course, the
type of resource consumption by the individuals in the
population.
In the
animal world the main resource consumed is food, which is a fairly
constant requirement. It may fluctuate somewhat due to such factors as
growth or seasonal energy needs, but on average the amount of food that
any organism needs to live is relatively stable. Since animals have few
resource needs outside food and water it is relatively easy (at least
conceptually) to establish the carrying capacity of a given environment
for a particular species.
Even
for humans, as we saw earlier, the amount of food we require to survive
varies within only a small range – say 2000 to 5000
kilocalories per
day, depending on our level of activity. What is variable, makes us
distinct from other animals and makes the question of human carrying
capacity more complicated is of course the level of non-food resources
that humans consume. This can and does vary all over the map. In the
previous sections we have been using energy as a proxy for all these
resources.
My
preferred definition of carrying capacity is:
The carrying capacity
of a given environment is the maximum number of individuals that the
environment can support sustainably at a given level of activity.
Sustainability
is defined as follows:
A sustainable process
or state is one that can be maintained at a certain level indefinitely.
A sustainable process or state should provide optimal conditions for
all organisms affected by it. A sustainable process or state must not
threaten, directly or indirectly, the viability of any of the organisms
affected by it.
Given
these definitions it is intuitively obvious that the current level of
human activity is not sustainable. The fact that it has been possible
at all is mainly because of the use of fossil fuel, a non-renewable
resource. That use is by definition unsustainable, and Peak Oil is
graphic evidence of that fact.
Overshoot
A species is said to be in overshoot if its numbers (or more properly, its aggregate level of consumption)
has exceeded the carrying capacity of its environment.
When a
population rises beyond the carrying capacity of its environment, the
existing population cannot be supported and must eventually decline to
match or fall below the carrying capacity. A population usually
cannot stay in overshoot for long. The rapidity and extent of the
decline depend on the degree of overshoot and whether the carrying
capacity is eroded during the overshoot, as shown in Figure 15.
William Catton's book "Overshoot"
is recommended for a full treatment of the subject.
There
are two ways a population in overshoot can regain its balance with the
carrying capacity of its environment. If the population stays
constant or continues rising, its activity (expressed in terms of per
capita resource consumption and waste production) must fall. If
per capita consumption stays constant, population numbers must decline.
Populations
in serious overshoot always
decline. This is seen in wine vats when the yeast cells die after
consuming all the sugar from the grapes and bathing themselves in their
own poisonous alcoholic wastes. It's seen in predator-prey
relations in the animal world, where the depletion of the prey species
results in a reduction in the number of predators. This population
reduction is known as a crash or a die-off, and can be very rapid.
Figure 15: Overshoot
It is
an axiom of ecology that overshoots degrade the carrying capacity of
the environment. This is illustrated in the declining "Carrying
Capacity" curve in Figure 15. In the case of humanity, our use of oil
has allowed us to perform prodigious feats of resource extraction and
waste production that would simply have been inconceivable without the
one-time gift of oil. Fossil fuels in general and oil in
particular have made it possible for humanity to stay in a state of
overshoot for a long time.
At the
same time, the use of fossil fuel and other high-intensity energy has
allowed us to mask the underlying degradation of the Earth's carrying
capacity. For instance, the loss of arable land and topsoil fertility (estimated at
30% or more since
World War II) has been masked by the use of artificial fertilizers
made largely from natural gas. Another example is the death of the
oceans, where 90% of all large fish species are
now at risk, and most fish species will be at risk
within 40 years. This situation would be calamitous for nations
that depend on the oceans for food, except that the use of fossil fuels
allow them to fish ever farther from their home waters or import
non-oceanic food to make up for the shortage of fish. Depleted water
tables can be supplemented by water pumped from deeper wells; air
pollution can be avoided by the use of air conditioners, etc. All of
these indicate that ecological decline is being conveniently masked by
our use of energy.
As our
supply of energy (and especially that one-time gift of fossil fuels)
begins to decline, this mask will be gradually peeled away to reveal
the true extent of our ecological depredations. As we have to rely more
and more on the unassisted bounty of nature, the consequences of our
actions will begin to affect us all.
It is
impossible to say with certainty how deep into overshoot humanity is at
the moment. Some calculations point to an overshoot
of 25%, others hint that it may be much greater than that. No
matter what that number "really" is, there is no
question of the damage
we have done to the natural systems of air, land and water that
supported us before the advent of coal, oil, and natural gas.
In
order to complete the population model, I have factored in a gradually
increasing effect from the unmasking of the world's loss of carrying
capacity. The effect increases over time for two reasons. The first is
simply that with less energy we won't be able to hide the existing
ecological losses as well. The second is more insidious: as our energy
supply declines we will do ever greater damage to the ecosphere in our
attempt to forestall the inevitable. One major example of this is the
increase in Global Warming that will come from the extra CO2 produced
by the coal we will burn to try and replace the energy lost from
declining oil and gas.
As in
other aspects of this model, aggregation has been used to make the
calculations more straightforward. In this case I have used a single
numerical expression for "ecological damage" that rolls
up all the
possible sources of damage into a single mathematical term. The damage
is assumed to come from a large variety of sources: climate change
(e.g. droughts, flooding and other extreme weather events), loss of
soil fertility, loss of fresh water supplies, the death of the oceans,
chemical pollution of land and water, and the loss of biodiversity due
to extinctions, habitat loss and monoculture food production. Such an
aggregation necessarily results in a loss of precision, and may
overstate or understate the actual situation. The chosen values
represent my best estimate of the current state of the global ecology.
The
model assumes that the impact of diminished carrying capacity will
start now, and will reach about 40% by 2100. This 40% number represents
the extent to which carrying capacity has been diminished and can no
longer be masked by energy use. This impact is applied directly to the
population numbers from Figure 14: an impact of 40% is taken to mean
that the world will be able to support 40% fewer people than it might
without the effect.
This
affects the scenario in a three ways. First, the maximum population is
slightly lower than it was in Figure 12. Second, the decline curve is a
bit steeper. Most importantly the ultimate population in 2100 is no
longer 1.8 billion, but just 1 billion people. Figure 15 shows the
final population curve.
Figure 16: World Population with Declining Energy and Carrying Capacity, 1965 to 2100
Discussion
The scenario developed in this paper is fearsome indeed, and most people
have an instinctive aversion to discussions of overpopulation or
die-off. In my opinion, however, an awareness of the possibilities
described here is essential if we are to make correct decisions on
actions and policy at both the personal and government levels. An
understanding of the problems of scale relating to energy sources is
fundamental to this awareness.
The
immediate objection to any worries about overpopulation is that
population is declining naturally anyway, and will soon stabilize at a
manageable number. The proper objective is therefore to hasten the fall
of fertility rates, usually through the education and empowerment of
women. Others claim that birth rates will fall naturally as poor
nations industrialize, through the behaviour described by the Demographic
Transition Model. We will examine each argument on its merits.
The
education and empowerment approach has much to recommend it. It is
humane, provides major benefits to societies where it occurs, and costs
very little in either economic or energy terms. It is a valuable tool
that must be promoted at every opportunity. Even in a resource-depleted
world of one billion people, communities where such principles are in
action will be much better off than those that hew strictly to the
dominant "masculine" principles of our civilization
(e.g. competition,
domination and exploitation). Empowering women improves the diversity
of values and makes more room for alternative social organizations,
expanded conflict resolution approaches and a better understanding of
humanity's relationship to our environment.
What
we should not expect is that this approach will make a significant
contribution to resolving the population problem
in the time we
have left. Education and empowerment take time, and there is far too
little time remaining before the first wave of impacts is upon us.
Where it will help is during the population decline. That decline will
be going on for many years, possibly for two or three generations.
During that time, any birth that is humanely avoided adds one less
person to the pool of those who are at horrifying risk of war, disease,
starvation and death. Under such circumstances I would expect birth
rates to fall dramatically anyway, but if we concentrate on educating
and empowering women we will make fertility reduction more likely,
along with improving the lot of those whose task it will be to keep
civilization running.
Proponents
of the Demographic Transition Model have a more difficult
time. That model proposes that as a society industrializes it goes
through two phases, the first consisting of rising life expectancies,
the second characterized by a drop in fertility. The society
transitions from a demographic situation of high birth and death rates
through one of high birth and low death rates, to one of low birth and
death rates. I have published a study
examining the energy that might be required to bring the world to a
stable or declining population by this method. The result of that study
was that it would take over five times the energy we use today to
accomplish this, which is clearly an unrealistic expectation.
This
leads naturally to the question, "Well, what if we come up with
a new
source that will give us the energy we need? What about fusion power or
some even more exotic source? Wouldn't that take care of it?" My
response is to suggest that the questioner take a hard look at what
we've done with the energy we do have. Using it we have strip-mined the
topsoil, drained the aquifers, destroyed the oceans, melted the
glaciers, changed the very temperature of the planet, and exterminated
untold other species in the process. Would more energy change that
behaviour? There isn't a chance in (what's left of) the world.
In any
event, if the conclusions of this model are anywhere close to correct
all these arguments are moot. Energy constraints will trigger a
reduction in population starting within 20 years, and the impact of
those constraints will far exceed anything that such humanitarian
measures could accomplish. In fact, if the model is correct, there will
be no ongoing overpopulation problem at all, as
natural processes
intervene to bring our numbers back in line with our resource base.
This
leaves the question of what such a population decline would look and
feel like. The details of such a profound experience are impossible to
predict, but it's safe to say it will be catastrophic far beyond
anything humanity has experienced. The loss of life alone beggars
belief. In the most serious part of the decline, during the two or
three decades spanning the middle of this century, even with a net
birth rate of zero we might expect death rates between 100 million and
150 million per year. To put this in perspective, World War II caused
10 million excess deaths per year, and lasted a scant 6 years. This
could be 50 times worse. Of course, a raw statement of excess deaths
doesn't speak to the risk this will pose to the fabric of civilization
itself. If it is true that the Inuit have a dozen words for "snow", we
will need to invent a hundred for "hard times".
Conclusion
All
the research I have done for this paper has convinced me that the human
race is now out of time. We are staring at hard limits on our
activities and numbers, imposed by energy constraints and ecological
damage. There is no time left to mitigate the situation, and no way to
bargain or engineer our way out of it. It is what it is, and neither
Mother Nature nor the Laws of Physics are open to negotiation.
We
have come to this point so suddenly that most of us have not yet
realized it. While it may take another twenty years for the full
effects to sink in, the first impacts from oil depletion (the net oil
export crisis) will be felt within five years. Given the size of our
civilization and the extent to which we rely on energy in all its
myriad forms, five
years is far too short a time to accomplish any of the unraveling
or re-engineering it would take to back away from the precipice. At
this point we are committed to going over the edge into a major
population reduction.
However, this does not mean that we
should adopt a fatalistic stance and assume there is nothing to be
done. In fact nothing could be further from the truth. The need for
action is more urgent now than ever. Humanity is not going to go extinct. There are
going to be massive and ever-growing numbers of people in dire need for
the foreseeable future. We need to start now to put systems, structures
and attitudes in place that will help them cope with the difficulties,
find happiness where it exists and thrive as best they can. We need to
develop new ways of seeing the world, new ways of seeing each other,
new values and ethics. We need to do this with the aim of minimizing
the misery and ensuring that as many healthy, happy people as possible
emerge from this long trauma with the skills and knowledge needed to
build the next cycle of civilization.
October, 2007
© Copyright 2007, Paul Chefurka. This article may
be reproduced in whole or in part for the purpose of research,
education or other fair use, provided the nature and character of the
work is maintained and credit is given to the author by the inclusion
in the reproduction of his name and/or an electronic link to the
author's web site. The right of commercial reproduction is reserved.
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ABOUT THE AUTHOR
Paul Chefurka is a Computer Scientist with a lifelong interest in environmental issues. He has spent over twenty years working in Research and Development in the Ottawa telecommunications industry, and is currently Project Manager at Canadian Coast Guard and the Canadian Department of Fisheries and Oceans. His personal web site, Approaching the Limits to Growth provides open access to his writings and is a valuable resource for study and reflection on many dimensions of the impending ecological crisis.
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