Human Population Grows Up Cohen (2005), Scientific American 2000 and beyond Old people outnumber young 2007 and beyond Urban will outnumber rural 2003 and beyond Median birth rate will be at or below replacement People living after 1930 were the first to experience a doubling of the human population : Fastest growth rate ever (2.1%) The most significant demographic event in human history After 1970 a steep drop (1.2%) AND mostly voluntary (exception – China?)

Developing vs. Developed 1950 – 2:1 ratio of human population 2050 – >6:1 Debate over composition of population largely ignored in Social Security reform Immigration Rapid but slowing Logic of compounds 1b added in yrs 2005 – x increase in the poorest countries (DRC, Liberia, Congo, etc). 50% increase in pop. will be from just 9 nations (U.S. in this list) – 1/3 of US growth from immigration

Demographics 1955 under 4yrs 14.% – 9.5% in yrs from 8.1% in 1960 to 10.4% in countries half of their population will be 23 yrs or younger Urban and Economics Poor countries will have to build the equivalent of a city of 1M+ people each week for the next 45 yrs. Economic (as compared to Demographic) models not well developed Per Capita Income ratio of industrial to developing – 16:1 in 1990 – 6.6:1 to 2.8:1 in 2050

Carrying Capacity 50% more people than now Currently have enough cereal grain for 10b – A vegetarian diet Capacity often measured in units of land, but this is too narrow – 1679 Antoni van Leeuwenhoek estimated 13b people CC based on estimates of Holland’s population and density – 2002 Mathis Wackernagel introduced ecological footprint concept Too narrow – based on single dimension of biologically productive land area Sustainability Too often attention given to long term as a diversion from the immediate task of tackling the issues today. More food means greater environmental impact using today’s BAU approaches Per Capita Income ratio of industrial to developing – 16:1 in 1990 – 6.6:1 to 2.8:1 in 2050