I need to get at least one more of these in. The landmark Limits to Growth has to date never been successfully debunked. Its conclusion that if we failed in the late 20th century to make drastic changes to zero out our population growth and limit resource consumption, we were likely heading toward a potential population collapse beginning somewhere between 2050 and 2100, and that the longer we wait to initiate global policy efforts toward zero population growth, the worse the collapse is likely to be. In the mid 1970s, the world population was 4 billion. Today it is more than 7 billion and by mid century it will likely be over 9 billion. The environmental pressures caused by population growth and per capita consumption by the world's rich and poor have led to resource depletion, soil degradation, ocean desertification, decrease in biodiversity and ecosystem eradication, climate change, etc. The world's energy and food supplies are likely near an all-time peak. Despite some local fossil fuel success stories, energy prices remain high and global supplies remain tight. Most power grids throughout the world are regularly taxed to their output limits. Continuing political destabilization and stagnant economic growth caused by access challenges to affordable food, potable water, and energy will likely be the big story of the first half of the twenty-first century. And a peak in the human population may be the big story of the second half.