Final answer:
Petroleum is a nonrenewable resource because it takes millions of years to form and cannot be replaced as fast as it is consumed. Our current usage rates will deplete petroleum reserves in decades, emphasizing the need for alternative energy sources.
Step-by-step explanation:
Petroleum is considered a nonrenewable resource because it forms under the Earth's surface over millions of years from the decomposed organic materials such as dead plants and animals. This long formation process means that once we have extracted and used petroleum, it cannot be replenished on a human time scale. At our current rates of consumption, petroleum reserves are depleting rapidly, and it is estimated that they will be significantly diminished within decades. Therefore, the crux of the matter is that the rate of consumption far exceeds the rate of natural formation, leading to a finite availability of petroleum.
Nonrenewable resources, like fossil fuels, also pose environmental challenges when burned, such as releasing pollutants and greenhouse gases that contribute to climate change. As a result, there is a growing emphasis on developing sustainable alternative energy sources to reduce our reliance on nonrenewable resources and mitigate environmental impacts.