Homo sapiens are dominating an increasing share of the mainland United States. Cities, towns, roads and other human land uses already shape about one-third of the landmass in the Lower 48 states, concludes a new analysis. By 2030, we could add a new “human footprint” the size of Indiana.

That forecast comes from a new approach to using digital maps to calculate the size of the human footprint developed by David Theobald, a geographer at Colorado State University in Ft. Collins. In the current issue of Landscape Ecology, Theobold uses a few basic factors – including vegetation, housing density, the existence of roads and highway traffic volume – to identify “human dominated” landscapes. In 1992, he found that humans had shaped up to one-third of the U.S. (or 2.6 million square kilometers). By 2001, that area had grown by another 80,800 square kilometers — and by 2030 he predicts natural areas could lose another 92,000 square kilometers (roughly the size of Indiana).

Wetlands are the ecosystem most likely to feel the boot, Theobold found. In 2001, 61% of wetlands were in or near landscapes modified by humans, compared to 15% of forested lands, 10% of grasslands, and 2% of shrublands. — David Malakoff

Source: Theobald, D. (2010). Estimating natural landscape changes from 1992 to 2030 in the conterminous US. Landscape Ecology, DOI: 10.1007/s10980-010-9484-z

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1 Comment

  • Steven Earl Salmony July 20, 2010 at 7:28 am

    A tribute to Professor Stephen H. Schneider of Stanford University…….thanks for speaking out so loudly and clearly, Steve. You will be missed.

    It appears to me that we are beginning to wrap our heads around the formidable predicament before all of us, thanks to great scientists like Steve Schneider. All of us share with him, I suppose, a passion for the study of the human condition, with particular attention paid to the colossal human-induced global predicament the human community faces in our time.

    Somehow we have to keep talking about this human-driven predicament, even if it happens to threaten leaders with vested interests in existing patterns of behavior. There is no other way forward that makes any sense to me.

    Human overpopulation of Earth is the number one problem, the proverbial “mother” of problems before the human family. It is so huge that all other global challenges, when taken together, do not present us with kind of colossal threat which is posed to us by the projected unbridled growth of absolute global human population numbers fully anticipated in the next four decades. There are many ways absolute global human population numbers could be dramatically reduced, either by human action or by natural occurrence. But if we have learned nothing about the predicament we are in now, others who come after us will likely make the very same errors that bring us now to this point in human history and space-time. Just now, I am reminded of Nietzche’s idea of the “eternal recurrence”. If we choose to willfully ignore scientific evidence, reason and common sense regarding human population dynamics and human overpopulation in order to satisfy the self-proclaimed Masters of the Universe among us who organize and manage the existing order of “life as we know it” for their own benefit primarily, then surely the colossal mistakes of the present will occur in the future, I suppose, over and over and over again. On the other hand, if top rank scientists with appropriate expertise, who have remained electively mute, speak truth to the powerful, and thereby fulfill their responsibilities to humanity and duties to science, then a chance exists for making necessary changes in the behavioral repertoire of human species leading us away from what can be seen now as unsustainable behavior and toward alternative ways of living in the world. Rightsized, human-scale business enterprises and sustainable lifestyles could become the order of the day.

    There have got to be similarly situated, top rank scientists in our planetary home who are ready now, here, to stand with Professor Stephen H. Schneider and Professor Emeritus Gary L. Peters in acknowledging the distinctly human-forced predicament confronting the human community; in overcoming the suppression of scientific evidence in silence; and in ending the collusion “underpinning” the global gag rule on open discussions of human population dynamics. We need many experts with the highest degree of skill and knowledge regarding population dynamics to speak out loudly and clearly regarding whatsoever is true to you, as best you can see and articulate what could somehow be real.


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