And creation of hydrocarbons consumes it, so it all evens out in the long run. The problem is that we're digging up deposits hundreds of millions of years old,

And creation of hydrocarbons consumes it, so it all evens out in the long run. The problem is that we're digging up deposits hundreds of millions of years old, so evening out over the long run means atmospheric CO2 goes back to what it was back then, which is much higher. But if you burn vegetable oil that you only grew this year, that doesn't emit any net CO2.