A World Transformed by Cancer

In 2150, the global population surpassed 10 billion. At the same time, Earth's environment underwent a drastic transformation. Desertification spread exponentially, and 90 percent of farmland became unfit for cultivation. The annual low temperature rose by five degrees in a single year, while the area covered by surface freshwater plummeted. Declining food production and recurring viruses caused the population to plunge from 10 billion to 4 billion. In order to survive, people flocked to the large cities, where resources were relatively concentrated. Within five years, urbanization reached an unprecedented 95 percent. Cities expanded one after another, growing into vast city-states. Before long, thousands of city-states had formed across the planet, each competing for resources and remaining independent of the others. More than 90 percent of society's resources were concentrated in the city-states, and humanity entered the “Age of City-States.”