Last month's column discussed money as an example of a concept that evolved from purely physical (a shell or attractive stone with inherent value), to a combination of physical and information (a gold coin of standard value), to primarily information (paper currency backed by the issuing authority's economic strength), to almost entire information (the modern electronic economy). The environmental implications of this example are complex and fascinating, but the general evolutionary trend this illustrates is also interesting.

Put very schematically and somewhat arbitrarily, one can parse human history into three phases representing increasing domination and manipulation of foundational systems. The first is the assertion of control over materials, the physical component of the environment. This began with the Paleolithic and primitive hand tools, and arguably is nearing its asymptote with the ascent of nanotechnology and quantum design, which extends that mastery to the smallest components of the physical world. The second is the assertion of control over energy, a process that began with fire, but is still ongoing; achieving fusion or the equivalent will mark both a profound change in resource availability to the species, and a logical asymptote for that process. The third is the assertion of human control over information, which is in its infancy but is obviously hitting its exponential acceleration phase with the invention and growth of the Internet, rapid growth in information and communication technologies (ICT), including the development and deployment of autonomic computing techniques, and continued rapid advances in fields such as artificial intelligence and cognitive science. In order of magnitude terms, learning to manage materials has taken about 100,000 years; energy, 1,000 years; and information may be estimated at perhaps 100 years. The latter may seem too short: consider, however, the speed with which biological information is being converted to intellectual property, or the growth of institutions such as Google and the Net, and it is at least a reasonable estimate.

Each revolution in human capability has created challenges and major changes. Looking only at environmental implications, the materials and energy revolutions have led to a single species -- us - being able to mobilize vast quantities of materials, restructuring biology and physical earth systems as we do so. The end result, from agriculture, to the often concomitant growth of hydrologic civilizations, to modern technological and urban human demographic patterns (a process that still continues) is the dawn of the Anthropocene (roughly, the Age of Humans). The result of increasing control over those domains is, in short, a planet increasingly dominated by one species -- ours. Even as industrialization continues, however, the next stage begins to play out: the creation of an encompassing information structure which culminates the process of anthropogenic creation of the human Earth. Moreover, it takes no more than a stroll through an airport, now clogged with people talking into thin air as they connect with friends, family and co-workers who are geographically distant; or a visit to a serious gamer's online life, to realize that the world is increasingly fragmenting into different sets of virtual experiences. These not only represent different sets of information within which individuals construct new cognitive systems, but they represent something very new: the Anthropogenic world is not just one where humans dominate global systems, but one where they invent new worlds and new systems. We are rapidly going from impacts on existing physical systems -- the climate, ocean circulatory patterns, biological structures at all scales -- to creating virtual complements with very different, and entirely anthropogenic, structure. In short, we are moving from dominating what is, to creating what will be from our imagination and the internal dynamics of our ICT infrastructures.

Environmental activists and scientists have both documented, and responded strongly against, human encroachment upon "natural" systems. They are, in other words, fighting against the tail of the asymptotic curves of the material and energy revolutions. But they have entirely failed to engage with the information revolution, a powerfully accelerating technological phenomenon that may well obsolete current mental models of environmentalism entirely. After all, when the power structure of the world is urbanized, fed by ICT systems and constructed content rather than observation of "natural" systems, and embedded in a number of virtual worlds of choice -- elements of modernity which are being instantiated now, not in some imaginary future -- it may well be that designing "nature" to support virtuality, rather than preserving "nature," becomes environmentalism. Whether this is a good thing is indeed open to question; but it can no longer be blithely ignored.

Brad Allenby is professor of civil and environmental engineering at Arizona State University, a fellow at the University of Virginia's Darden Graduate School of Business, and previously was AT&T's vice president of environment, health, and safety.