We already appropriate something like a fifth of primary photosynthesis productivity via agriculture and other harvests of non-agricultural productivity, and it’s unclear how much more you can appropriate before you start really messing with ecologies we depend upon (more than we already are at least). To give an idea how this translates into energy terms, a third of the vast American corn harvest is turned into biofuel to produce something like ten percent of our automotive fuel, itself only a portion of energy use (Though the high-intensity farming used to cram large amounts of corn productivity per acre themselves use a lot of that fuel, so the net energy produced is less than it would seem. Between running the fields and fermenters I believe the consensus is that a given amount of ethanol energy actually requires between 50% and 80% of that energy in fossil fuel to be burned to produce it.)
Geologically processed fossil fuels are ridiculously dense in energy and represent a portion of hundreds of millions of years of photosynthetic productivity.
We already appropriate something like a fifth of primary photosynthesis productivity via agriculture and other harvests of non-agricultural productivity, and it’s unclear how much more you can appropriate before you start really messing with ecologies we depend upon (more than we already are at least). To give an idea how this translates into energy terms, a third of the vast American corn harvest is turned into biofuel to produce something like ten percent of our automotive fuel, itself only a portion of energy use (Though the high-intensity farming used to cram large amounts of corn productivity per acre themselves use a lot of that fuel, so the net energy produced is less than it would seem. Between running the fields and fermenters I believe the consensus is that a given amount of ethanol energy actually requires between 50% and 80% of that energy in fossil fuel to be burned to produce it.)
Geologically processed fossil fuels are ridiculously dense in energy and represent a portion of hundreds of millions of years of photosynthetic productivity.