I revamped my consumption model to take account of ecological footprint going back over 500 years, and was able to closely predict population growth over that period. Looking ahead, it pushed out by 20 years the amount of time we have before our population crashes. My goal was to reliably estimate the time in history when we each used the amount of resources we must use in the future to avoid losses in our population and the crash of other species’ populations. The answer, depending on how long the world reduces the annual rate of consumption before settling at a fixed amount of consumption per year, is some 300 years ago, at the start of the Industrial Revolution.
Put another way, the world must increase its efficiency of per capita resource use by a factor of about 100 to keep our population from falling after it peaks, and by a factor of several hundred to keep other species’ populations from crashing. Interestingly, our (western) economy wastes roughly 100 pounds (in production and packaging) for every pound of product used (not counting externalities such as gas emissions and energy use during transportation), implying that we would need to extract only those resources that we actually use while cutting out the other costs.