Notes from Midterm Group Study


  • Arose from Ehrlich & Holdren vs. Commoner in the 1970s
  • ImPACT variation separates production (GDP/pop) and consumption (
  • Some variations have 1/T instead of T, reflecting belief that technology reduces impact
  • Problems with IPAT
    • Implies you can "solve" for any variable, e.g. technology
    • Variables are not independent
    • Environmental degradation in one area does not equal real impact (only looking at nitrogen, CO2, etc)


  • long-term, global scale, systems-thinking
  • integrating info flows & feedbacks, intersection of natural & social systems
  • appropriate scale: biosphere is closed system, all systems within it are open