What does Earth’s energy budget describe?

• A. The balance between incoming solar radiation and outgoing energy from Earth
• B. The balance between wind and humidity
• C. The balance between rainfall and evaporation
• D. The balance between atmospheric pressure and temperature

Answer: (A)

Earth’s energy budget describes the balance between energy entering from the Sun and energy leaving back into space. The Sun pours energy toward Earth, some is reflected back by clouds and the surface (albedo), and the rest is absorbed, warming the planet. Earth then radiates heat outward as infrared energy. In a stable climate, the amount of energy absorbed roughly equals the amount radiated away over time; any excess energy tends to raise global temperatures, while a deficit cools the system. Greenhouse gases influence how easily heat escapes to space, tweaking the budget and thus the climate. The other options refer to moisture, rainfall, evaporation, or atmospheric state, which are important climate processes but do not describe the global energy balance itself.