All layers are incredibly important. If we didn't, we would die very quickly and life would be inhabitable. The radiation from the son would kill us. The heat from the sun would dry up water and kill crops leaving us with no food/water.
Among all the countries that you mentioned, Gabon is the country that receives the most rainfall.
The concept of Peak Oil was first developed in the 1950's by the geologist M. King Hubert.
