Final answer:
Nuclear power, a nonrenewable energy source, is expected to be less available in the next 40 to 60 years due to finite uranium reserves and increasing energy demands.
Step-by-step explanation:
Among nonrenewable energy sources, nuclear power is likely to become much less available in the next 40 to 60 years. Current estimates suggest that proven uranium reserves could last around 90 years at the present rate of usage. However, should the reliance on nuclear energy significantly increase, due to either a decrease in fossil fuel availability or a shift away from carbon-intensive energy sources to combat global warming, these reserves could be depleted much faster.
Nuclear energy is implicated in environmental concerns, such as the safety and disposal of nuclear waste. Combined with the finite nature of uranium, this underlines the importance of transitioning to renewable energy sources. Efforts to develop and expand renewables like solar and wind energy are essential to ensure a sustainable energy future as reserves of nonrenewable resources dwindle.