"Was Marx a degrowth communist?"

The answer to this absurd question is obviousy "no," but this Monthly Review essay sets out reasons for that conclusion (despite its somewhat idiotic hostility to G.A. Cohen's interpretation of historical materialism  [which has problems, but not the one this essay remarks on], it adduces the relevant textual evidence).  The "Saito Schtick" about Marx's ecological prescience is a classic case of trying to hitch one's au courant agenda to the authority of a "great thinker."  Marx had no idea about climate change, and despite reading about problems like deforestation, soil depletion, and 19th-century analogues of factory farming from the 1860s onwards, he never saw fit to write seriously about any of it in the multiple volumes of Capital.   And one would not know, from reading the "degrowth" hysterics, that the world population will start declinding well before this century is over.  The Marxian vision of productive abundance, even within the ecological constraints he was unaware of, remains quite realistic--and far more realistic than the sociological idealism of Saita & company.