It's the population, stupid -- part I
Thanks for Charles Bowden's grim but clear-eyed view of events along the border and Jonathan Thompson's editorial relating them to too many people and too much consumption (HCN, 3/1/10). There's no doubt that our addiction to consumption creates social and environmental costs, but I have a quibble regarding Thompson's statement that it is "the most important variable" behind environmental impacts. Both individual consumption and the number of consumers matter, a lot. In fact, the "beautiful, and sometimes deadly, precision" that characterizes the arithmetic of population growth tells us exactly how long it will take for population growth to erase any increased efficiency that we gain by living more lightly on the land. Population growth, like compound interest, feeds on itself; if the growth (or interest) rate is N percent per year, it takes 0.7/N years for the number of population units to double. Put another way: The U.S. population is now doubling in size in about 40 years, so if every one of us miraculously and instantly changes our lifestyle to halve our use of fuel, electricity, food and land, those gains will be erased by population growth by 2050.