The exacerbated (economic and ecological) crisis and the failure of conventional theories and policies aiming at eco-regulation and sustainable development of capitalism make it imperative to consider this socio-ecological crisis from an anti-systemic, communist perspective. This article is an attempt to articulate a unified and integrated interpretation of this socio-ecological crisis, based on a dialectical conception of the relationship between society and nature. The over-accumulation, rising organic composition of capital, and falling rate of profit play a central role in the analysis of this crisis and the articulation of its particular forms. As argued, capital’s strategic response to crisis and the deep restructuring of capitalism cannot ensure ecological and social sustainability, and more importantly the requirements of a socially acceptable human development. While there is some evidence of a recurrent accumulation and crisis, we are rather witnessing a secular downturn of capitalism and all attempts or tendencies towards “dematerialization” or “decoupling” of capitalist production (and growth) from its detrimental ecological impact fail to effectively encounter the root causes of crisis. An attempt is finally made to draw the “broad contours” of an alternative, communist outlook in overcoming this socio-ecological crisis, and a working-class strategy ensuring the conditions of sustainable human development and an ecologically compatible society.