Population, Consumption and
our Ecological Footprint
This is yet another run at the perennial question of the relative importance of overpopulation versus overconsumption.

I recently wondered how much each nation in the world would contribute to the eventual ecological degradation of the planet given their current ecological footprint and their projected population growth between now and 2050.

To explore this I decided to use a variation on the familiar ecological "equation" I=PAT. In the original formulation, I is the impact we have on the planet, P is population, A is the per-capita activity level and T is the level of technology.

For this exploration, I used the populations of countries around the world today and in 2050, and their current calculated per-capita Ecological Footprint (EF) expressed in in global hectares (Gha) per person. For background on the concept of the Ecological Footprint, go here.


  • I used  a spreadsheet list of countries with their per-capita ecological footprints from the Global Footprint Network.
  • I matched each country with its current population from Wikipedia and its projected population in 2050 based on the US Census Bureau's International Database.
  • The final list consisted of 150 countries with populations over 1 million.
  • You can find the spreadsheet with my original data and the calculations here (XLS).
  1. I first multiplied the per-capita EF for each country by the its population to get the total number of global hectares needed by that country today and in 2050.
  2. I summed each set of national numbers to get two total global values for the Gha needed today and in 2050.
  3. I took the difference between the two national values to get the increase (or decrease) in total EF for that country over the next 40 years.
  4. I took the difference between the two global values to determine the increase in total EF for the world over the next 40 years.
  5. Dividing the national increase by the world increase gave the proportion of the total increase contributed by that country.

While the world's population went up 38% between now and 2050 in my little simulation, the global Ecological Footprint went up by only 27%. That confirms the fact that much of the world's population growth over the next 40 years will happen in lower-impact countries.  However, that won't offset the increasing ecological damage we will continue to inflict on the planet as our footprint expands.

If the human race is already in a 40% overshoot situation today, then by 2050 we could be into a 70% overshoot. 
It was not surprising that the United States contributed the lion's share of that 27% increase - 27% of the increase was from the USA.

What did surprise me was that Ethiopia and Nigeria finished in the top 5 thanks to their overwhelming projected population increases.

Another thing that was surprising was that only 35 countries showed a net negative contribution to the global increase, and that only 4 countries - Italy, Spain, Russia and Japan - helped slow the increase by more than 1%

The best showings were from Japan and Russia, whose precipitous population declines gave them a 3% net benefit.

Here are the top ten contributors to the increase in planetary ecological damage over the next 40 years:

Ecological Footprint and GDP

It's intuitive that a country's Ecological Footprint should correlate with its GDP, because raising GDP generally involves  placing more stress on biocapacity for both resource extraction and waste disposal.

I can't recall ever seeing a plot of Ecological Footprint against GDP, so I decided to create  one.  I used per capita Ecological Footprint data from the Global Footprint Network and per capita GDP from Wikipedia, and did an Excel scatter plot of the values:

The correlation is about what I'd expect.  The trend is obvious, but there are lots of outliers (countries with high GDP and relatively low EF, and vice versa).

What this implies to me is that if a country's GDP goes up or down its Ecological Footprint will tend to follow. It also implies that reducing a country's footprint while maintaining or increasing its GDP is going to be quite difficult.

While we all want to decrease our impact on the planet, this is yet another warning that such efforts are not cost-free.


December 4, 2009

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