FAST: All people fall over and rot.
SLOW: Universal human infertility.
The carnage would be easily integrated into the food chain by scavengers and maggots, but our clever machinery could cause gigantic problems for Earth.
Major appliances like stoves and cars could be absorbed, but nuclear reactors would begin to melt down or explode and, tragically, no humans would be around to appreciate the fireworks. Without someone there to hear them, they might not make a sound. For miles around every reactor, a radioactive zone would exist for a very long time, as the timeline below depicts.
Abandoned oil wells, landfills, and coal mines would eventually stop burning. Dams would fail and cause much local destruction of ecosystems. Impact would vary depending on which dam in a series broke first.Unless plant and animal life downstream increases and expands before the dams break, more species could be flushed away.
Toxic waste would migrate into the water cycle, and would eventually be dispersed throughout the planet, re-collecting in pockets. Mutations and adaptations by lower life forms would allow life to continue in spite of the poisons. However, most animals higher on the food chain would be unable to adapt fast enough.
In short, biodiversity would be set back five to ten million years. On the bright side, Earth’s biosphere would soon begin to get better, reversing the direction of the past 15,000 years of human activity.
The Times Online projects our extinction into the future
Gradual extinction of the human race will result if zygotes of Homo sapiens never again begin cell division.
Abortion providers might be the first to notice—happily going out of business in a few months. A worldwide panic might set in, but without reason. There would be no negative impact on the world nor on society as a whole.
Individuals’ lives could change profoundly, but all for the good. Starving people would begin finding enough to eat and resources would become more plentiful. New housing would be unnecessary.
All human technology would be scaled back but could still advance. Nuclear power plants could begin to be safely decommissioned. Dams could be removed. Technology could focus on dealing with unsolved problems such as radioactive and other toxic wastes. Healing the wounds of past exploitations could become a priority, reversing the expanding deserts and shrinking forests.
Some of our influences, such as climate change, may be impossible to stop and reverse at this point, but we could ameliorate the effects somewhat.
Conditions for society would also improve as shortages are eliminated and our death rate drops to an unheard of low.
Domestic plants and animals could be phased out as farms and ranches are converted to ecosystems supporting wildlife and natural vegetation.
The last humans could enjoy their final sunsets peacefully, knowing they have returned the planet to as close to the garden of Eden as possible under the circumstances.
The last one out could turn off the lights.