The increase in thermal energy on Earth can lead to various effects on plants. Out of the provided responses, the most accurate would be: Plants produce more pollen.
Higher temperatures can accelerate plant growth and reproduction, potentially leading to increased pollen production in some species. However, it's important to consider that extreme temperatures can also stress plants, which may reduce growth or lead to fewer plants in some ecosystems. So, the response that fits best within the context is that plants may produce more pollen due to increased thermal energy.