Answer:
Methane, which generally produces more heat and energy got decreased in the Earth's system, leading to less energy in the Earth system and less energy absorbed by Earth's surface.
Step-by-step explanation:
Methane produces a great deal of energy than any other gas that plays a role in the greenhouse effect. In several billions of years ago, humans were not engaging in activities that could increase the amount of methane in the earth's system most especially the atmosphere. Such activities that were not done include burning fossil fuel, raising livestock as we have now, and waste disposal. Natural process which includes natural air reduces some amount of methane in the atmosphere.