Disagree, it's just that the safe level is around 0.1% of current use (though I don't just mean use of fossil fuels for electricity, I mean *everything*).

There’s applications that we still have no alternative for though - e.g. aviation - so we’ll have to accept the burning of hydrocarbons there.

Not fossil hydrocarbons forever, of course, but synthetic kerosene might be a thing soon enough.

I don't know what you mean with "no safe level of fossil fuel use". It doesn't mean anything without contextualizing that statement.