What would a decrease in the concentration of greenhouse gases in the atmosphere mean for the conditions on Earth? ANSWERS The thickness of the atmosphere would increase, effectively increasing the pressure felt on Earth. The atmosphere would trap more heat, and the overall temperature of Earth would increase drastically. The day and night temperatures on Earth's surface would vary more wildly. The available liquid water would vaporize, and the sea level would increase as a result. The atmosphere would trap less heat, and the overall temperature of Earth would decrease.