Which natural factor is a cause of climate change?

Variations in solar energy reaching Earth significantly impact climate change as they directly influence global temperatures and weather patterns. The Earth's climate is affected by the amount of solar radiation that penetrates the atmosphere and reaches the surface. Changes in solar output can occur due to natural cycles such as sunspot activity and the Earth's elliptical orbit around the sun, which can lead to variations in climate over time.

In contrast, increased manufacturing emissions, urbanization and deforestation, and the expansion of industrial agriculture are primarily human-induced factors contributing to climate change. These activities release greenhouse gases into the atmosphere, altering natural processes and accelerating climate change beyond what would occur due to natural variations alone. Therefore, the variation in solar energy is the correct answer as it represents a natural and cyclical factor affecting the Earth's climate.