What is the main source of energy for the Earth's climate system?

The Sun is the primary source of energy for the Earth's climate system. Solar radiation drives atmospheric and oceanic circulation, influences weather patterns, and is critical for photosynthesis in plants, which is foundational to the food web. The energy received from the Sun heats the Earth's surface, leading to temperature gradients that result in wind, precipitation, and various climatic conditions. This solar energy is fundamental to maintaining life on Earth and shaping the Earth's various environmental systems.

While the Moon influences tides and has some impact on climate (like affecting ocean currents), it does not provide energy in the way the Sun does. The Earth's core generates heat through radioactive decay, contributing to geological processes rather than directly impacting climate. Volcanic activity can release energy and materials into the atmosphere, but it is not a consistent or primary energy source for the climate system. Thus, the Sun remains the indispensable energy source that drives the Earth's climate.