I am not as worried as Harvey about Marxism succumbing to "the rhetoric of the environmentalists." Historical materialism is a mode of inquiry (and a form of revolutionary praxis) that, if it has any lasting meaning, develops in response to changing conditions and new vernacular traditions.(1) The Vulnerable Planet was originally inspired by an essay entitled "The Vulnerable Earth: Toward a Planetary History" by U.S. environmental historian Donald Worster.(2) I wrote the book with two thoughts uppermost in my mind: that a historical materialism that did not embrace environmental issues was - in this day and age - hopelessly inadequate; and that an environmentalism not rooted in historical materialism was hopelessly lost. I am convinced that Marx's critique of the political economy of capital also contained within it the fundamental elements of a political-ecological critique of capitalism. Yet to deal with ecological problems today, the classical legacy of Marxism is not enough, and must be supplemented with some of the insights of contemporary radical ecology.
These days skepticism toward science is widespread. Nevertheless, I was unprepared for Harvey's contention that the views of the World Scientists' (referring to the "World Scientists Warning to Humanity" signed in 1992 by over 1,500 senior scientists including more than half of the recipients of the Nobel Prize among living scientists - see my article above) "are every bit as problematic as the literature they rebut." In his book Harvey refers to Greg Easterbrook and Julian Simon as examples of the opposing, anti-environmental (self-styled "ecorealist") point of view.(3)
Among those who signed the World Scientists' Warning we find figures like Hans Bethe, Robert Gallo, Stephen Jay Gould, Stephen Hawking, Jane Lubchenco, Howard Odum, Linus Pauling, Ilya Prigogine, Carl Sagan, James Watson, and Edward O. Wilson. The credibility of scientists such as these in this area has to be considered far beyond that of an establishment journalist like Easterbrook who ends his book by assuring his readers that we can "terraform" Mars if we run out of ecological space on earth, thereby giving us "two biospheres for every one that exists today."(4) Simon, for his part, is a conservative, anti-environmental economist, best known as a proponent of what has been called the "weak sustainability hypothesis": the idea that increases in economic wealth as measured by the market can substitute completely for any losses in natural wealth.
In dismissing the World Scientists' Warning Harvey claims that their metaphor of a "collision" of humanity with the earth is "abstract and ideological." Yet, this ignores the significance of this particular metaphor within contemporary science. The most recent of the great mass extinctions (there have been five extinctions in which 65 percent or more of species died out in a brief geological instant) was quite likely the result, many scientists now believe, of the collision of an asteroid with the earth some 65 million years ago - the end-Cretaceous extinction resulting in the demise of the dinosaurs. Hence, the collision metaphor implicitly invites a direct comparison of the human impact on the earth with that of the probable cause of the fifth mass extinction. Recently, scientists have warned that we are on the verge of "the sixth extinction" - this time at the hand of humanity.(5)
I rubbed my eyes in disbelief when reading Harvey's charge that I had slipped into Malthusianism by referring to the "Malthusian term overpopulation" - in a litany of environmental problems on the opening page of chapter one of my book - and by "approvingly" quoting the Ehrlichs and other Malthusians at various points in my writing. It is news to me that "overpopulation" is simply a "Malthusian term." Marx and Engels pointed to the possibility of overpopulation, as have many Marxists and socialists. In his very first essay on political economy, for example, Engels observed that,
Even if Malthus were completely right, this transformation [i. …