What does the term 'fossil sunlight' mean in Geology?

 

This refers to the energy from the sun that is found captured inside fossils of various kinds over millions of years through the natural process of photosynthesis. Oil, coal, gas and other forms of fossil fuels, which were typically formed over many millennia from the remains of dead plants and animals that absorbed energy from the sun, begin to release the energy that is trapped inside them when they are burned for human uses. Since the process of energy storage usually takes millions of years to occur — while their exploitation by human beings is quite rapid — energy stored in fossil fuels is generally considered to be a non-renewable or limited resource.