"At Australia’s Bunny Fence, Variable Cloudiness Prompts Climate Study.“ So reads the headline in an article by Sonal Noticewala in The New York Times (14 Aug 07). The piece explains that "a fence built to prevent rabbits from entering the Australian outback has unintentionally allowed scientists to study the effects of land use on regional climates. The rabbit-proof fence – or bunny fence – in Western Australia was completed in 1907 and stretches about 2,000 miles. It acts as a boundary separating native vegetation from farmland. Within the fence area, scientists have observed a strange phenomenon: above the native vegetation, the sky is rich in rain-producing clouds. But the sky on the farmland side is clear.“ The accompanying aerial photograph is startling in how clouds on one side and complete cloudlessness on the other follow the straight line of the bunny fence.
The infamous rabbit-proof fence was built in response to unintended consequences. Rabbits had been introduced to Australia by white settlers. There were no predators to limit their numbers and the long-ears quite literally reproduced like rabbits, becoming thick as flies in vast areas of the continent. The fence to control unintended numbers of bunnies has now produced its own unintended consequences. It has created a pattern where on the rabbit-free side of the fence, agriculture has exploded, leaving the flora on the other side au naturel. "Within the last few decades, about 32 million acres of native vegetation have been converted to croplands west of the bunny fence.“ And this, in turn, seems to have its own unintended consequences. "On the agricultural side of the fence, rainfall has been reduced by 20 percent since the 1970s.“
Scientists scramble to explain what is causing this precipitation disparity. "Researchers … have come up with three possible explanations for this difference in cloudiness. One theory is that the dark native vegetation absorbs and releases more heat into the atmosphere than the light-colored crops. These native plants release heat that combines with water vapor from the lower atmosphere, resulting in cloud formation."
"Another hypothesis is that the warmer air on the native scrubland rises, creating a vacuum in the lower atmopsphere that is then filled by cooler air from cropland across the fence. As a result, clouds form on the scrubland side."
"A third idea is that a high concentration of aerosols – particles suspended in the atmosphere – on the agricultural side results in small water droplets and a decrease in the probability of rainfall. On the native landscape, the concentration of aerosols is lower, translating into larger droplets and more rainfall.“
This waking nightmare serves as a reminder how little we humans knows about the ecosystems in which we live. We have little understanding of how any action, even such a seemingly inert one, as erecting a fence, will impact the complex living system in which it is nested. All human dreams regarding goals and aspirations must be humbly and continuously reality-checked: what, really, is happening from implimenting the dream? What needs to be done differently? How do we adjust the dream so that it doesn't become malignant? Otherwise, dreams in their implimentation all too easily become waking nightmares.