Which step(s) of the greenhouse effect are being most affected by the increases in greenhouse gases, leading to an increase in heat?1. Solar radiation enters the Earth system and is reflected and absorbed.2. Absorbed energy is released into the atmosphere as heat.3. Heat is absorbed by the atmosphere.4. The atmosphere re-releases heat, warming Earth’s surface and lower atmosphere.

Increasing greenhouse gases most directly affect steps 3 and 4: they absorb more of the heat (infrared radiation) emitted by Earth and re-release some of it back toward the surface and lower atmosphere. This traps more heat in the Earth system. They do not significantly change the incoming solar radiation in step 1 or the initial release of absorbed energy as heat in step 2.

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