We can gain some insight into the two possible trajectories of consumption by looking at how the ecological footprint (presumed to be proportional to annual consumption by mass) changes on a per capita basis.
According to my consumption model, the per capita footprint will climb to nearly 35 times its 1990 value by 2047 before crashing along with the last of the population. Alternatively, if the per capita growth rate of the footprint persists on its 40-plus year path, the footprint will peak eight years from now and then fall to practically zero over the following 23 years. We could either radically increase our impact on the planet (by four times its ability to replenish resources), enjoyed by a rapidly decreasing few, or we could exceed the planet’s replenishment rate by two-thirds before all of us suffer a rapid decline in resource use and population.
We may not have enough energy to pursue the high-consumption trajectory, though if global warming gets out of control it may continue on its own – without the benefits of increased lifestyle (which I estimate would peak at an average $2.4 million per person). My bet, however (subject to change by future enlightenment, not to mention actual events) is on the second option.