though I'm on general principle friendly to Cass's "eco-socialism" argument I have to take exception  to this traditionally blinkered definition of "productivity".

the only base of productivity, as in "sustaining life of mammals like us," is photosynthesis.  without trees, there would be no mammals.  without sunlight and the hydrological cycle there would be no trees, no food, no fibre, no fuel.  without ancient trees and the saurians whose life they enabled and the climate they preserved, there would be no oil fields for us to loot.

all "production" on Earth is due to the external input of sunlight and the momentum of planetary rotation and the gravitational forces of tides etc.  humans can usurp that productivity, concentrate it (as by feeding plants to animals and then eating the animals), loot existing stores of it (as in eating wild-caught large predator fish, or liquidating topsoil with extractive agriculture, or oil extraction) but the fact remains that the only "productivity" on earth's surface is the process of self-organising and complex biotic systems.  in the mantle and core there are residual energies from the process of planet-formation, but these are not (pace Starvid and NNadir) directly transmutable into support for mammalian life forms.  we cannot eat geothermal heat, or magma, or uranium.  when we burn coal and oil we are merely squandering at an astounding release rate the stored productivity (and carbon) of many evolutionary ages of surface biota.

all too often, human activities miscalled "productive" are actually dissipations, dispersals, destructions, liquidations of the stored energy of biotic processes.  it imho is a mistake -- a very serious error -- to call any activity "productive" if it extracts minerals from the mantle and squanders fossil energy on refining them, extracts soil productivity without replacing it, reduces the complexity of ecosystems, reduces species count, transfers toxins and mutagens into air and water, disrupts nutrient cycles, disrupts hydro cycles, and/or damages the genome of the animal or plant realms.  such activities are counter-productive -- entropic.  they are using up and vandalising the only sources of real wealth.  all the cowrie shells or krugerrands or gold moidores or theoretical "return on investment" numbers in a prospectus will not replace that oil in the ground or refill the Oglalla Aquifer.

in this sense a healthy wetland or watershed, undamaged, is far more productive if sequestered from capitalist (or communist for that matter) vandalism than the same land turned into a polluted, compacted, overpaved factory site or suburban subdivision.  as we are, increasingly and to our sorrow, discovering...

capitalism is not just about the accumulation of cowrie shells in a few pockets;  it (and industrialism in general) is about the massive accelerated liquidation of the stored energy of biotic systems, both present and past.

The difference between theory and practise in practise ...