I understand that the sun gives energy primarily in the form of sunlight, which contains various wavelengths of electromagnetic radiation. If the earth absorbs some of the energy, does the earth’s “total energy” accumulate?
In: Planetary Science
The Earth radiates the same amount of energy out as it gets from the sun. If it didn’t, the temperature of Earth would quickly become too hot to survive.
When the light of the sun hits Earth, most of it bounces back without doing anything. Some of it heats Earth up, but that heat will eventually radiate away into space, so the long-term increase is nothing.
Earth actually radiates away 20X photons than it absorbs. That’s because processes on the planet (mostly life) will absorb and convert light to other forms of energy, then use it and generate heat. That causes it to radiate away over time in the form of infrared.
So the long-term net gain from the Sun to Earth is zero. The problem with climate change is that greenhouse gases make it harder for Earth to radiate away energy. That means more of the sun’s energy stays on Earth longer, which causes the planet to convert more highly organized energy into disorganized energy. That causes the temperature to increase while we wait for that energy to eventually radiate away again.
The process of converting highly dense and usable energy to less dense energy is called entropy. There’s a really excellent ELI15 (https://www.youtube.com/watch?v=DxL2HoqLbyA).
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