Which of the following is a natural cause of atmospheric changes?

• A. Changes in the Sun's energy/solar radiation
• B. Emissions of CO2
• C. Deforestation
• D. Industrial pollutants

Answer: (A)

The energy the Sun provides to the Earth is the natural driver of atmospheric changes. Over time, the Sun’s output varies due to natural cycles and longer-term fluctuations, so more or less solar energy reaches Earth. When solar energy increases, the atmosphere tends to warm; when it decreases, cooling can occur, influencing temperatures, wind patterns, and weather on various time scales. In contrast, emissions of CO2, deforestation, and industrial pollutants come from human activities and alter the atmosphere’s composition and radiative properties, driving changes that are not natural fluctuations. So, the natural factor shaping atmospheric changes is the Sun’s changing energy input.