A few weeks ago I took a dive into the empirics of life expectancy. How can we live longer, I asked, without consuming more energy?
In the past, we’ve used fossil fuels as a crutch. To increase life expectancy, we’ve consumed loads more energy. Figure 1 shows the trend across all countries.
Although using more energy does increase life expectancy, it’s not a sustainable option for the future. Increasing energy use by an order of magnitude (from 10 GJ to 100 GJ per person) only gives about 20 extra years of life. That’s not efficient. And it’s certainly not sustainable.
So the question is, how can we increase life expectancy without using more energy? To answer this question, it’s helpful to define something called the ‘energy-life-expectancy residual’. This is the difference between a country’s life expectancy and the international trend.
Figure 2 shows some examples. Here the black line is the international trend between life expectancy and energy use per capita. I’ve highlighted 4 countries that depart sharply from this trend. The average Nigerian, for instance, lives 12 fewer years than expected from the energy-life-expectancy trend. The average Costa Rican, in contrast, lives about 10 years longer than expected from the trend. Similar discrepancies occur at higher energies. The average Russian lives 4 years less than expected from the international trend. The average Netherlander lives 7 years longer than expected.
Winners in the game of life
In Living the Good Life … Without Killing the Planet, I took a stab at seeing what causes these energy-life-expectancy residuals. The results sparked much discussion. A common request from readers was to see which countries were doing ‘best’ and which were doing ‘worse’.
Here’s what the data says.
Figure 3 shows the countries that are winning the game of life. These are the 10 countries that have most improved their energy-life-expectancy residuals.
Let’s unpack what this means. First of all, it’s not about the overall increase in life expectancy. Rather, I’m measuring the change in life expectancy relative to the international trend. In other words, the countries in Figure 3 have beat the average.
Most of these countries have drastically increased life expectancy without using more energy. Some countries (like Tajikistan and North Korea) have even managed to increase life expectancy while decreasing energy use. Seeing North Korea on this list is a bit surprising, given its bizarre brand of kleptocratic communism. Living longer, it seems, doesn’t require freedom or free markets.
I’m not an expert on international development, so I’d like to hear your thoughts about what’s going on here. Why are these countries winning the game of life?
Losers in the game of life
Now let’s turn the table and look at the countries that are losing the game of life. Figure 4 shows the 10 countries whose life expectancy has decreased the most relative to the international trend.
Notice that other than Eswatini and Namibia, all of these countries have increased their life expectancy in absolute terms. But they have done so slower than the international trend. In other words, greater energy use has paid off less than expected.
Interestingly, half of these countries are island nations (St. Vincent, Seychelles, Tonga, St. Lucia, Grenada). These nations had higher life expectancies to begin with. When they increased their energy use, it seems that life expectancy regressed towards the mean.
And what’s going on in Eswatini? (It’s also known as Swaziland.) From 1990 to 2007, Swazi life expectancy collapsed — decreasing from over 60 years to less than 45 years. I’m no expert, but I suspect we’re seeing the results of the HIV epidemic. According to Wikipedia, a quarter of all Swazi adults are HIV positive — the highest rate anywhere.
Zero sum, by definition
I’ll close by noting that the game of life, as I’ve defined it here, is zero sum. I’m measuring life expectancy relative to the international trend, which means that there are always going to be winners and losers. Because of this fact, I don’t think that beating the international trend should necessarily be a policy goal. It would be perverse for all countries to try to ‘beat the average’, since by definition, that’s impossible. Still, it’s interesting to see which countries do better (in relative terms) than others. The harder task is to figure out why this is happening.
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Sources and methods
Energy use data is from the World Bank series EG.USE.PCAP.KG.OE. I’ve added an estimate for the energy consumed though food (2000 kcal per person per day). Life expectancy (at birth) is from the World Bank series SP.DYN.LE00.IN.
I calculate the energy-life-expectancy trend (in Figures 1 and 2) using a locally-weighted polynomial regression. Residuals are then measured as deviations from this regression.
I’ve defined ‘winners’ and ‘losers’ as follows. In each country, I measure the energy-life-expectancy residual in the first available year and last available year. ‘Winners’ have the greatest difference between the two observations. ‘Losers’ have the smallest (i.e. most negative) difference between the two observations.