Final answer:
An increase in the transparency of Earth's atmosphere can be due to reduced air pollution and aerosol levels, which allows more sunlight to pass through and warm the planet's surface. This transparency change affects the greenhouse effect and is influenced by human activities such as fossil fuel combustion and deforestation.
Step-by-step explanation:
An increase in the transparency of Earth's atmosphere is often caused by a reduction in air pollution and aerosol concentrations. Factors that can affect the transparency include changes in the greenhouse effect, variations in the sun's energy reaching Earth, and changes in the reflectivity of Earth's surface and atmosphere. When the atmosphere is cleaner, more sunlight can pass through, potentially leading to more direct warming of the Earth's surface. Conversely, increases in greenhouse gases, such as carbon dioxide (CO₂) and methane (CH₄), enhance the greenhouse effect by absorbing and re-radiating infrared radiation back to Earth, thus increasing Earth's surface temperature. Overall, transparency is largely influenced by both natural processes and human activities such as the burning of fossil fuels and deforestation, which alter the concentrations of greenhouse gases in the atmosphere.