Part 8: Searching for evidence of population decline during periods of declining petroleum consumption

Well, it is good to be back—blogger lives!

In part 7, I examined the correlation between global population and petroleum consumption and presented  two possible scenarios for population change in light of declining petroleum production.   The first scenario (Figure 25, Part 7) posited a continued increase in population even in the face of the predicted decline in petroleum production decline, with a subsequent population decline, perhaps after the mid-century.  The second scenario (Figure 28, Part 7) posited a decline in population, “a die-off,” starting now in direct step with the predicted decline in petroleum production. 

Here in part 8, I present the evidence that caused me to reject the second scenario.

Perhaps you will be surprised, but there is plenty of evidence to show that the population can increase even in the face declining rates of global petroleum production or regional petroleum consumption.

Evidence of continued global population increases in the face of declining petroleum consumption in the early 1980s

For instance, Figure 29 revisits the relationship between global population and global petroleum production from 1950 to 2009 previously presented in Figure 27.   This time, however, I focus on the period from 1979-1982 (corresponding to the period of the 1979 energy crisis and the Iranian Revolution) when global production/consumption declined by about 14 percent. 

 Nevertheless, the global population still increased during this period by 235 million (4.54 billion to 4.86 billion).  

Table 14 shows the results of a linear regression analysis population versus time to estimate the global annual population change (i.e., the slope; r² = 0.99 or higher for all periods) for the three periods in Figure 29 where petroleum production/consumption was either increasing or decreasing:

Table 14: Rate of global annual population change for periods of increasing and decreasing petroleum production rates
Range	Petroleum Production rate trend	Population change (millions / year)
1950-1979	increasing	64
1979-1982	decreasing (-14%)	78
1982-2009	increasing	79

As you can see, the 14 percent decline from 1979-82 appears to have no effect on decreasing the population growth rate.  Rather, the growth rate actually increased relative to rate during the preceding period from 1950-1979.  Then, even though production/consumption rates increased after 1982, the population growth rate stayed the same.

Okay, you might say, “maybe we aren’t seeing a population decline because the world is not as dependent on petroleum-driven food production as more developed regions like North America or Europe?”

No, there is still no support for population change being linked to petroleum consumption in these regions, at least not since 1965. 

Evidence of continued regional population increases in the face of declining petroleum consumption in North America (NA) and Europe (EU)

Figures 30 and 31 shows the analogous plots for NA and EU, of population versus petroleum consumption rates from 1965 (which where the BP statistical review data set starts).  There are two longer periods of production rate increase from 1965-1978 and 1983-2006, and two shorter periods of production rate decline from 1979-1983 and 2006-2009.  Table 15 summarizes the population growth rates (millions/year, mil/yr) during each of these periods.

Table 15: Rates of regional annual population change for periods of increasing and decreasing petroleum production rates in North American and Europe
Range	Petroleum consumption rate trend	NA Population change (mil/yr)	EU Population change (mil/yr)
1965-1979	increasing	4.10	3.25
1979-1983	decreasing (-16% NA; -18% EU)	4.22	1.97
1983-2006	increasing	4.77	1.20
2006-2009	decreasing (-9% NA 5% EU)	4.33	1.43

From 1979-83, relative to their respective previous periods, for NA, with a 16% decline in consumption rate, the population growth rate increased slightly, while for EU during the 18 % decline in consumption rate, the population growth rate decreased.  However this population decline in EU continued during the subsequent period from 1983-2006 when the consumption rate increased and then decreased from 2006-2009.  The decline in the population growth rate in EU appears to be unrelated to these changes in the petroleum consumption rate.  In contrast for NA, during these same periods (1983-2006 and 2006-2009) the population growth rate remained comparatively constant.

Note, however, throughout all of these periods we are still seeing a positive population growth rate.  That is, the population in these regions continues to increase.

Alright, you might say, “maybe we aren’t seeing a population decline here because the relative change or duration of the periods of the petroleum consumption rate decline were not long enough to affect petroleum-driven food production?” 

No, that’s not it either...

Evidence of continued regional population increases in the face of large declines in petroleum consumption in the Former Soviet Union (FS)

Figure 32 shows the plot of population versus petroleum consumption rate for the FS.  Table 16 shows the annual population change for the periods shown in the figure and discussed below.

Table 16: Rate of regional annual population change for periods of increasing and decreasing petroleum production rates for the Former Soviet Union
Range	Petroleum consumption rate trend	Population change (millions / year)
1965-1979	increasing	2.35
1989-1990	flat	2.35
1991-1999	declining (-54%)	-0.13
2000-2009	increasing	-0.61

After a steady climb from 1965 to 1979, from 1980 to 1990 the consumption rate stopped increasing and remained flat in a narrow range around 3.1 bbs/yr.  The population during this period continued to increase at about the same annual rate.

Then, from 1991to 1999, there was a dramatic decline in consumption (corresponding to the dissolution of the Soviet Union) from 2.98 to 1.36 bbs/yr—a 54% decrease in 9 years! 

However, the annual population growth rate was essentially flat (-0.13 mil/yr).  Moreover for the first 5 years during this period, the period with the greatest decline in consumption rate (a 48% decrease by 1995 compared to 1990 levels), the population change was still positive (+.19 mill/yr).  Since 2000, there is a trend for a steeper negative population growth rate.  But, this is occurring while petroleum consumption rates have increased by 9% in 2009 compared from the rate in 2000.   Once again, these trends don’t support the notion of population change being linked to petroleum consumption rates.

Okay, okay, you might say, “maybe we aren’t seeing a population decline here because we need to look at petroleum rate consumption declines in developing regions, not developed regions?”

Closer, I believe, but still, there is no evidence to support this.

Evidence of continued regional population growth rate increases during period of petroleum consumption rate decline in South America (SA) and Asia Pacific (AP)

Figures 33 and 34 shows the respective plots of population versus petroleum consumption rate for the SA and AP, and Table 17 shows the annual population change for the periods shown in the figures and discussed below.

Table 17: Rates of regional annual population change for periods of increasing and decreasing petroleum production rates in South America and Asia Pacific
Range	Petroleum consumption rate trend	SA Population change (mil/yr)	AP Population change (mil/yr)
1965-1979	increasing	5.80	45.8
1979-85 (SA); 1979-82 (AP)	decreasing (-5.5% SA; -9.7% AP)	6.41	45.23
1986-2009 (SA); 1983-2009 (AP)	increasing	6.12	44.6

SA and AP also experienced brief periods of mild consumption rate declines in the early 80s—but this did not have a negative effect on population growth/ 

“What about the other developing regions?”

Since 1965, there has not been a sustained downturn in petroleum consumption in the Middle East (ME) or Africa (AF), and, the regional population growth rate these

Figures 35 and 36 show the respective plots of population versus petroleum consumption rate for the ME and AF.  Table 18 shows the population change for the same periods discussed above for NA and EU in Table 15.

Table 18: Rates of regional annual population change for periods of increasing and decreasing petroleum production rates in Africa and the Middle East
Range	Petroleum consumption rate trend	AF Population change (mil/yr)	ME Population change (mil/yr)
1965-1979	increasing	10.1	2.27
1979-1983	increasing	14.6	3.88
1983-2006	increasing	17.3	3.68
2006-2009	increasing	22.1	4.29

There never has been a significant disruption in petroleum consumption rates for these regions and so these plots are not useful for testing the idea that a decline in consumption would result in a decline in population growth.  They do show clearly, however, that the population growth rate is increasing for both of these regions.

Summary and Lessons from the Regional Analysis

Well, if you have hung with me through this analysis this far, and have been paying attention, I think that you will agree that there is little to no support here for the notion that just because petroleum consumption rates go into decline, that we are likely to see an immediate decline in population, or, even neccessarily a decline in the population growth rate.  In Part 7 I said correlation does not prove correlation. I think that the regional analysis here demonstrates this point nicely: even though pouplation and petroleum consumption have been increasing over the same period there is little evidence to show that the total consumption for any of these regions was a cause of the population increase.

I found that the results for the former Soviet Union quite interesting: a 54% decrease in petroleum consumption rates over 9 years (6%/yr) is associated with a declining population growth rate, but even then, the population growth rate didn’t turn negative until five years into the consumption decline.  And, the population growth rate didn’t turn positive again in the last nine years when the petroleum consumption rate has been increasing.

Similarly, the four year decline in the petroleum consumption rate in North America (4%/yr), in the early 80s, or, the present three-year of decline in consumption (3%/yr for NA) is not associated with a decline in population growth rates during these periods. 

Europe’s population growth rate has been declining, but is still positive, and the decline in growth rate has occurred regardless of whether the petroleum consumption rate was on an upward or downward trend.  This is similar to the same trend over the past nine years in the former Soviet Union: population growth rates slowly declining. 

The smaller declines in petroleum consumption rates in South American and Asia Pacific in the early 80s appeared was also not associated with a decline in population growth rate for these regions. 

Finally, both population growth and petroleum consumption rates have been on upward trends in Africa and the Middle East.

In summary, my analysis for these several regions as well as the global data do not support the idea of there being an immediate causal link between the direction of change in total petroleum consumption rates and the direction of change in population.  In other words, I don’t find support for the idea that reaching and passing the point of peak oil production rates mean that there is going to be an immediate die off.

Therefore I feel comfortable rejecting my scenario represented in Figure 28 in Part 7, namely that a decline in global population is imminent as global petroleum production goes into decline, as predicted in Part 6 of this series. 

Rather, my scenario of continued global population growth such as shown in Figure 25, and along the lines of Cribb’s expectations, seems closer to the mark.

However, I still don’t think that the scenario depicted in Figure 25 tells the whole story—there is a point where total petroleum production, and hence consumption for these regions, and globally, will decline below a level that can support the food production system as we have come to know it. 

After reflecting on these results, I believe that it was just that the total levels of consumption in NA, EU, FS, SA, AP, AF and ME, during the downturns in petroleum consumption rates, were still probably more than  enough to support the food production system, and therefore, there was no famine or population decline.

Therefore, I propose a new hypothesis:

The population will continue to grow in these seven different regions of the world, at least until the per capita petroleum production/consumption drops below a certain critical level that is needed to support a petroleum-driven Green Revolution.  Once production per capita declines below that critical level, I expect to see a decline in the region’s population, in proportion to the per capita petroleum consumption rate decline. 

So just how much petroleum consumption per capita is needed to sustain the food production system as we know it?  I will attempt to answer this question in the ninth part of this series, and, use my findings to refine my prediction of how population will change in the face of declining petroleum production.  I hope that you will join me.