system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: If oil is made from decomposing algae breaking down in the seafloor from millions of years ago, and Algae is constantly growing, dying, and decomposing, why isnt oil being constantly produced as more decomposed algae is ready?
gpt
A lot of fossil fuels were produced in an era where living things didn't decompose as easily as they do today, because many of the decomposers hadn't evolved yet. This is especially true of coal, which dates to an era before fungi figured out how to break down the lignin in wood.

But even insofar as fossil fuels are being produced today, they are produced **very** slowly. Think about it: in basically a century, humanity has used a big chunk of the total oil available on Earth from *hundreds of millions of years* of oil production. In other words, we're using oil ~a million times faster than the Earth has historically produced it.