[WalterBright]

Consider that so many thousands of companies are involved in the manufacture of the lowly pencil that there is no possible way to even determine the carbon footprint of it. Howinell can that work with a gigantic company like Microsoft? How can Microsoft's auditors come up with a remotely credible number? (They can't.)

But what makes it all work is the pricing mechanism of the free market, not some auditing system.

See Milton Friedman "Free to Choose"