Numerous problems have been predicted as an outcome of an increasing global population, including water shortages, food crises, resource depletion, and global warming, with the world population predicted to reach 9~10 billion by the 22nd century. Stabilizing populations relatively quickly would be beneficial, and could be achieved by financially supporting developing countries to promote the education of women, which would help decrease birth rates. In addition, a two-child policy would be highly effective if it were adopted by the United Nations. Water shortages are already a serious issue and population stabilization should be accelerated to minimize further shortages. Conversely, the world food stock is sufficient to support the global population, so food crises are political problems that will not increase in severity after population stabilization. In addition, energy resources could support a stabilized population for at least for the next 153 years if unconventional fossil fuels are used. Moreover, there is sufficient thorium to supply all primary energy for 58 years, while sea uranium could provide energy for 1,000 years if used in light-water reactors or for two billion years if used in fast breeder reactors. Nuclear waste will be disposed of into the Sun via space elevators within 50 years. The progression of global warming is decelerating in the 21st century, probably due to inactivity of the sun, and mitigating global warming will not be necessary if the sun remains inactive. Even if solar activity increases, reducing CO2 by 50% would only mitigate global warming by 0.7 K by 2050 and cause huge economic losses. Instead, we should focus on developing techniques to prevent devastating earthquakes, catastrophic volcanic eruptions, and giant meteorite impacts.