Marxism has long been subject to criticism from the theorists of Political Ecology, and in recent years, as the concerns of Green thinkers have become harder to ignore, Marxists have begun to respond to this challenge, defending and sometimes amending Marxist theory in response to Green criticisms. This chapter addresses one issue within this debate: the controversy over Marx's commitment to the growth, or development, of the productive forces. My aim is to dispute the contention of Marx's Green critics, that his concept of the development of the productive forces leads inevitably to the exacerbation of ecological problems, and, more speculatively, to suggest some advantages of using this concept to investigate ecological problems.¹