Question

when the levels of greenhouse gases in earths atmosphere increase, which statement is true? earths temperature increases because h_in increases. earths temperature increases because h_out increases. earths temperature increases because h_out decreases. earths temperature increases because h_in increases and h_out decreases.

Explanation:

Green - house gases in the atmosphere trap heat. $H_{in}$ represents the heat entering the Earth - system (mostly from the Sun) and $H_{out}$ represents the heat leaving the Earth - system. When greenhouse gas levels increase, they block the heat from escaping, reducing $H_{out}$. The incoming heat $H_{in}$ remains relatively constant in the short - term. As a result, the net heat in the Earth's system increases, leading to a rise in temperature.

Answer:

Earth's temperature increases because $H_{out}$ decreases.