What is Earth's carrying capacity for humans?

• A. The geographic distribution of populations
• B. The current population growth rate
• C. The maximum number of humans that Earth can sustain indefinitely given resources and technology
• D. The average births per 1,000 people per year

Answer: (C)

Carrying capacity is about sustainability: the largest population Earth can support indefinitely given the available resources and technology. It isn’t just about how fast the population grows or where people live; it’s about the long-term balance between resource supply (like food, water, energy, land) and the demands of the population, including consumption and waste that ecosystems must absorb. Technology can help stretch that limit by making production more efficient or reducing waste, but it doesn’t remove the fundamental constraint of finite resources. So the statement that defines carrying capacity as the maximum number of humans Earth can sustain indefinitely given resources and technology best captures the concept.