The overall design is based on the saying ‘Is the glass half full or half empty?’ But in this version we are looking at the earth and how much oil is remaining. The overall image is a glass version of earth which is half full of oil.
See examples Earth1, Earth2 and Earth3, for how earth might look. Even though it should be clear, the earth should look more 2D than 3D.
The top half of the earth is empty except for the land which should be a more transparent version of the land used in the bottom. You could highlight the outline of the land in the top half with a darker translucent outline and then the colourful oil in the middle.
The colour of the oil is also really important. See examples Oil1, Oil2 and Oil3 to get an idea of what the oil might look like. In the bottom half of earth the oil will be mostly a dark colour, but it should have some character to it and not just be plain black. Also the land should be highlight with the bright colours that oil can make in the examples Oil1 and Oil2.
Overall I have done a quick sketch of what it may look like in Sketch 1. As you can see by my drawing skills I need your help to bring it to life!