by Roberto — As prob­a­bly all STC read­ers are al­ready well-aware, the end of ex­po­nen­tial growth of the hu­man pop­u­la­tion is near. The dou­bling time for hu­mans to go from 2 to 4 bil­lion was about fifty years. The pop­u­la­tion main­tained pretty much the same dou­bling time go­ing from 4 to 8 bil­lion.