None of us have any choice in the matter, but, via LiveScience, one scientist has studied the relationship between age and carbon emissions, and suggests that after age 65, people's carbon footprints get smaller. This means that as the Baby Boomers pass the age 65 mark, we may see carbon emissions start to decline, according to Emilio Zagheni, a research scientist with Germany's Max Planck Institute for Demographic Research.

Using data available for U.S. residents, Zagheni compiled how much Americans of different ages spend on nine energy-intensive products and services, including electricity, gasoline and air travel. He then assigned carbon dioxide emissions weights to these and combined them into a single carbon dioxide emissions profile. He found that as they age, Americans consume more and more of these things, producing more carbon dioxide as a result. This trend peaks around age 65, and then much of it reverses. Older people tend to spend more on their health, which generally produces lower levels of greenhouse gas emissions. This also reduces the money they have to spend on other, more energy-intensive things. However, since they are spending more time at home, the use of electricity and natural gas continues to rise among people until they reach 80.

Zagheni suggests that as the last of the Baby Boomers start retiring around 2030, we will still see emissions rising until 2050 or so. However, the U.S. population is growing, too, but Zagheni's calculations suggest that increasing emissions from a growing population will counteract any effect from aging, although not as much as one would think. Zagheni's paper appears ion the current issue of the journal Demography.