What environmental issue is caused by pollutants in the troposphere reflecting the earth's radiant heat back to earth?

The correct answer is based on the understanding of how certain pollutants interact with the Earth's atmosphere. Global warming refers to the long-term increase in Earth's average temperature due to the buildup of greenhouse gases, such as carbon dioxide and methane, which can trap heat in the troposphere. These gases absorb and emit radiation, leading to a greenhouse effect that prevents radiant heat from escaping back into space, thus contributing to rising global temperatures.

This phenomenon is distinct from ozone depletion, which primarily involves the thinning of the ozone layer in the stratosphere due to substances like chlorofluorocarbons (CFCs) and does not directly relate to the warming effects in the troposphere. Global cooling refers to a decrease in Earth's average temperature, which does not align with the question's context of heat retention. Climate change is a broader term that encompasses global warming and other shifts in weather patterns, but when specifically addressing the direct effects of pollutants trapping heat, global warming is the most accurate term.