That's not the argument in full. Carbon cost of production includes the cost of wastage. If the cost in carbon to produce what is wasted is > than the savings e

That's not the argument in full. Carbon cost of production includes the cost of wastage. If the cost in carbon to produce what is wasted is > than the savings elsewhere, it is a loss. It is not so much a complicated equation as it is an involved one, and we risk simplifying the equation and getting it very wrong.