Carbohydrates provide a source of energy by the conversion of Starch or cellulose to glucose. However, the body needs lipids due to the great amount of energy it produces when broken down.
Excess Energy or lipids is usually stored in the body as adipose tissues. They are later converted to energy when the body is in dire need of them. They could provide a great amount of energy for up to a month.
Earth's natural resources are unevenly distributed across the globe this can be explained by geological process like the movement of tectonic plates erosion and volcanic activity.