Individual CO₂ emissions decline in old age

November 07, 2011

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Age distribution of annual carbon dioxide emissions of an average U.S. resident

Age distribution of annual carbon dioxide emissions of an average U.S. resident

© MPIDR, Emilio Zagheni

© MPIDR, Emilio Zagheni

For the first time, demographer Emilio Zagheni of the Max Planck Institute for Demographic Research in Rostock (MPIDR) has calculated a profile that illustrates the relationship between age and average per capita CO₂ emissions. This profile applies to U.S. citizens, as data for this group were easily accessible. But the demographic-economic model developed for the analysis is universally valid, and can be applied to other countries.

Carbon dioxide projections, like those of the Intergovernmental Panel on Climate Change (IPCC), depend greatly on future population developments. Most projection models only take into account the anticipated size of populations, but not their age composition, which will change considerably as life expectancy increases. According to the United Nations, the worldwide share of people aged 65 and older will grow from around eight percent currently to around 13 percent by 2030.

Zagheni’s profile suggests that societies with a growing share of elderly people will tend to produce lower CO₂ emissions—at least in developed countries with consumption patterns similar to those of the U.S.A. This is because people appear to do less damage to the climate after the age of 65. As they enter retirement, Americans are producing more carbon dioxide emissions than at any other point in their lives: i.e., around 14.9 metric tons per person annually. Thereafter, the amount produced decreases continuously, falling to 13.1 metric tons by age 80. No data are available for higher ages, but it is expected that emissions fall further. The impact of this age group on climate projections will be significant. This is because, while life expectancy in the U.S. is currently (2010) 78.3 years, it is projected to rise to 83.1 years by 2050, according to the U.S. Census Bureau. Moreover, life expectancy is expected to be even higher in other developed countries.

In order to calculate the per capita emissions profile, Zagheni compiled figures on how many dollars an average U.S. residents spend at different ages on nine energy-intensive—and thus CO₂-intensive—products and services, including electricity, gasoline, and air travel. By assigning carbon dioxide emissions weights to the consumption of these goods, he combined the nine consumption profiles to produce a single CO₂ profile.