February 28, 2008

Conservation in an Age of Climate Change

The February 4, 2008 issue of High Country News featured a cover story entitled, "Unnatural Preservation", by Martin Smith and Fiona Gow. In this article, Smith and Gow ponder a question that managers and scientists increasingly face while trying to do their jobs in a warming world: "Do we rush to rescue climate-imperiled species before it's too late? Or do we let nature take its course, quietly watching the disappearance of species that we have spent decades restoring and protecting?" There is no doubt that global warming will in coming decades, profoundly reshape the Earth's ecosystems, but can we really manage these changes? Do we move species to higher elevations and latitudes as their historic habitat becomes too warm? Do we remove "nonnative" species that colonize national parks and wilderness areas as a consequence of warming temperatures? Do we water ecosystems in response to the drying conditions that will accompany climate warming in many regions of the world?

There are several reasons that humans cannot play the role of "gardeners and zookeepers" as envisioned by Smith and Gow. First, the magnitude of the problem is far beyond our ability to manage. The Earth contains tens of millions of species, most that remain undescribed. These species and their ecosystems are excruciatingly complex, and this complexity will for the foreseeable future remain well outside of the realm of human comprehension. To pretend that we can manage the Earth's diversity and ecosystems to mitigate effects of global warming is delusional. Second, the gardener and zookeeper approach would by necessity focus on the most obvious ecosystem components, charismatic fauna and flora such as grizzly bears and giant sequoias, condors and saguaros. Managing even these relatively few and well-studied taxa would be an immense undertaking and this targeted approach would completely ignore the myriad other, less conspicuous taxa that often are at least as important as the charismatic species in determining ecosystem structure and function. And third, playing the role of the Earth's gardener and zookeeper requires understanding how ecosystems function, and to be blunt, we haven't a clue. A well-informed ecologist might be able to provide a rough sketch of how a corn field functions, but when it comes to natural, complex ecosystems, forget it. Even our best attempts to manage this diversity would do far more harm than good.

Our best hope of mitigating the effects of climate change is not frantic, poorly-informed attempts to manage the consequences, but instead to deal seriously and immediately with the driver of global warming: the build-up of carbon dioxide and other greenhouse gases in the Earth's atmosphere. Despite the enormity of that task, it pales in comparison to what would be required to manage the Earth's fauna and flora to mitigate the effects of climate change. No matter how effective the response of human societies is to rising greenhouse gas emissions, global warming will accelerate for decades to come. As these resulting changes to the Earth's ecosystems unfold, we'll have little choice but to watch.

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