The Earth is not yet an artifact

n the previous article in this issue [1], Brad Allenby argues for a more active style of planetary management. He notes, " the biosphere itself, at levels from the genetic to the landscape , is increasingly a human product. " While the earth is undoubtedly being transformed by human action [2]-[4], the implications of the transformation for environmental management are in dispute. Allenby suggests that the scale of human impact makes it appropriate to treat all landscapes as human products, subject to active management aimed at goals we collectively define. I question Allenby's claim that " there are no 'natural' systems anymore " [1], and question the utility of engineering based management methods as tools for planetary management. In contrast to Allenby, I suggest that we learn to control our environmental imprint before embarking on active planetary management. Allenby defines " Earth Systems Engineering and Management " (ESEM) as " the capacity to rationally engineer and manage human technology systems and related elements of natural systems in such a way as to provide the requisite functionality " [1]. The goal is active environmental management as opposed to minimization of environmental impact [5, p. 76]. In advocating ESEM, Allenby stresses the extent of human transformation of the environment, arguing, " the earth has become a human artifact " [1]. He implies that, if the world is an artifact, then it is naïve to try to maintain a landscape in its natural state, and naïve to practice stewardship [5, p. 84]. I argue that while one may accept that artifi-ciality demands active management , one ought to reject the claim that the world is now artificial. It is undeniable that the boundary between natural and human systems is fuzzy. Likewise, it is fair to characterize the world's landscapes as ranging from heavily to lightly managed, and to be wary of unreflective characterization of any landscape as wild. Yet the claim that the earth has become a human artifact seems far too strong. Most landscapes are in the middle ground, and the details of this middle ground matter in disputes about environmental management. In arguing for the world's artifi-ciality Allenby notes that some degree of human influence can be detected everywhere; for example, that trace metals mobilized by bronze age smelting can be detected in the Greenland icesheet. The argument that any trace of humanity makes a landscape unnatural assumes that true nature …