Homo sapiens began as a small-group species 160,000 years ago and remained tribal until the Agricultural Revolution about 10,000 years ago. Exponential growth began at that time and accelerated during the Industrial Revolution until, during the 20th century, the population doubling time was less than the human life span in some countries. In the latter part of the 20th century, the ecological overshoot rose to 24%, which meant humankind was exceeding Earth s carrying capacity. In addition, global heating and other types of climate change threatened to reduce food supplies, while population continued to grow. About one-half the population lived reasonably successfully in urbanized areas, although post-peak oil would probably make this undertaking more difficult. Most important, nations had not developed world governance to manage such problems as: (1) global heating and other types of climate change, (2) acidification of the oceans, (3) regulation of carbon dioxide [which affects both problems (1) and (2)] and other greenhouse gases, (4) stabilization of the human population within Earth s carrying capacity, (5) equitable and fair allocation of resources among humans and with the 30+ million other life forms with which humans share the planet, (6) management of the global commons, (7) requiem for reason. In order to address these global problems successfully, humankind must quickly develop global governance systems that transcend national limits so that the biospheric life support system is restored to and maintained in a healthy condition.