I recently came across a series of calculations on energy use that really caught my attention.  The analysis studied the rate of increase of energy use in the United States from 1650 to today.  That rate has been 2.9% per year.  Compounding. 2.9% doesn’t sound all that alarming, and by itself wouldn’t make a significant difference in global warming.

But what would happen if that seemingly modest rate of energy use growth were applied worldwide and continued to compound year after year? At some time in the not too distant future would it become insupportable and destructive to the global ecosystem?

The math is astounding! In only 1,390 years from now, that rate of energy growth would take Earth from a trivial rock orbiting the sun to an energy output EQUAL to the sun! If that is not surprising enough, continuing the trend another 1,600 years, our planet would have an energy output equal to our Sun plus every other star in our Milky Way galaxy!

Current concerns about global warming are mostly related to the greenhouse effect due to increased carbon dioxide in the atmosphere. But before long the greenhouse effect will be insignificant compared to the waste heat generated by all that energy production.

It is all too apparent that sometime before the year 3501 we will have to curb our appetite for continuous energy output growth. That is far in the future and we could let our distant descendants deal with it. But should we? Don’t we who share this pale blue dot have an obligation to design our civilization in a way that avoids destroying the planet that nurtured us to begin with?