[adammarples]

Well oil is "green". Burning oil releases carbon dioxide which is plant food and contributes to global greening. This isn't good, because it also contributes to global warming, but I don't really understand why people conflate "green" with renewables. The greenest the planet has ever been was during the carboniferous period, where plants had feasted on unusually high levels of atmospheric co2.

[JuniperMesos]

The color green has long been symbolically associated with environmentalist political causes, because the earliest environmentalist concerns were about literally-green plants being replaced by human-made machinery that is typically brown and grey. The fact that, today, the biggest environmentalist political concern is atmospheric CO2, and the fact that one effect of larger amounts of atmospheric CO2 is literally more green, photosynthesizing plant life, is a true enough fact; but not really relevant to the color symbolism.

[paulddraper]

Oil is usually clear or light yellow.

It can be darker colors too.

[outside1234]

Exactly! The best way we can make the world green again is to make Florida an underwater reef.