I am thinking that rather than reducing the NUMBER of people we should just reduce their SIZE drastically. Through genetic engineering and selective breeding we could probably reduce the average human size by fifty percent over a few generations.
Think of the energy savings and the abundance of natural resources that could be conserved. A current home could shelter several families, a single cow may feed a village for maonth, and cars would get so much smaller that we could “widen” freeways by merely re-striping them. What a paradise.
Of course, special exemptions will be established for NFL and NBA players.
Steve Martin advocated this way back in the 1970s with his Let's Get Small routine.