To be honest, I'm not sure exactly what this is. It sounds like a Good Thing, but from a quick skim it's rather arcane in that way that policy wonks tend to write and think. I think/guess it may be to do with measuring RoI by things other than money. Good. I guess the want a standardised way of doing this, in the way that GDP/GNP are standard, because standardisation makes comparison easier. Some people have tried to put a price on the ecosystem, so that it is included within capitalism and doesn't break its rules (liquidising assets and calling it income, ignoring externalities and others.) If I ever get around to looking into it more I'll blog further.