What is Earth's estimated carrying capacity range?

The estimated carrying capacity of Earth refers to the maximum population size that the planet can sustain indefinitely without leading to environmental degradation. Option C, which suggests a range of 2-40 billion, is considered accurate based on various studies and models that take into account factors such as natural resources, food availability, and environmental constraints.

This range acknowledges the complexity of ecological and sociopolitical factors that influence how many people Earth can support. For example, advancements in technology and agricultural practices can potentially increase food production, thus supporting a larger population. However, it also takes into account potential limits imposed by resource depletion, climate change, and habitat destruction, which could affect sustainability.

In contrast, narrower ranges such as 1-10 billion or 10-20 billion do not fully encompass the potential for future advancements and changes that could allow for a more significant population if managed sustainably. The higher ranges, such as 40-60 billion, may overlook the critical limits posed by environmental systems, leading to negative impacts on quality of life and ecosystem health. Thus, the chosen range of 2-40 billion reflects a balanced view of the various dynamics at play in calculating the Earth’s carrying capacity.