Tuesday, December 27, 2005

Oops! Sorry 'Bout That

As a continuation from my previous entry, I'm going to offer but a few examples of human-caused unintentional consequences. Often, these consequences come about innocently...at least at the outset.

The European Rabbit is not native to the Australian continent. According to Wikipedia,
Rabbits were originally introduced to Australia by the First Fleet in 1788, but the current major infestation appears to be the result of 24 wild rabbits released by Thomas Austin on his property "Barwon Downs" (near Winchelsea, Victoria) in 1859 for hunting purposes. Many other farms released their rabbits into the wild after Austin.
Here we have a classic example of unintended consequences. A landowner decides he'd like to hunt rabbit. So, without giving any regard to the effects on the ecosystem, he sets in a motion a chain of events still ravaging Australia today.
Within ten years of the 1859 introduction, the original 24 rabbits had multiplied so much that 2 million a year could be shot or trapped without having any noticeable effect on the population size. Rabbits reached the New South Wales border in 1870. The Premier of New South Wales, Sir Henry Parkes offered a £25,000 reward to anyone who could come up with a solution to the rabbit infestation.

The effect on the ecology of Australia was devastating. One eighth of all mammalian species in Australia are now extinct (rabbits are the most significant known factor), and the loss of plant species is unknown even at this time.
English ivy makes for lovely ground cover. It's a very popular plant amongst gardeners in North America. Unfortunately, english ivy is not native to this continent. The United States National Arboretum cautions
In the Pacific Northwest, English ivy invades the forest floors. Its evergreen leaves smother other native forest plants by denying them light.
Like english ivy, asian carp is another invasive species that has caused great harm in the U.S. Some of the carp were released into U.S. waters by our own government and others escaped from aquaculture facilities.
All four of the Asian carps that are established in the United States spread quickly after introduction, became very abundant, and hurt native fishes either by damaging habitats or by consuming vast amounts of food. Common and grass carps destroy habitat and reduce water quality for native fishes by uprooting or consuming aquatic vegetation.

Bighead and silver carps are large filter-feeders that compete with larval fishes, paddlefish, bigmouth buffalo, and freshwater mollusks (clams). In addition, boaters have been injured by silver carp because they commonly jump out of the water and into or over boats in response to outboard motors. Black carp, which consume almost exclusively mussels and snails, may further threaten our already imperiled native freshwater mussels should they become established.
Dioxin is one of the world's most toxic family of chemicals. As explained by ActionPA,
Dioxin is a general term that describes a group of hundreds of chemicals that are highly persistent in the environment. The most toxic compound is 2,3,7,8-tetrachlorodibenzo-p-dioxin or TCDD. The toxicity of other dioxins and chemicals like PCBs that act like dioxin are measured in relation to TCDD. Dioxin is formed as an unintentional by-product of many industrial processes involving chlorine such as waste incineration, chemical and pesticide manufacturing and pulp and paper bleaching. Dioxin was the primary toxic component of Agent Orange, was found at Love Canal in Niagara Falls, NY and was the basis for evacuations at Times Beach, MO and Seveso, Italy.

Dioxin is formed by burning chlorine-based chemical compounds with hydrocarbons. The major source of dioxin in the environment comes from waste-burning incinerators of various sorts and also from backyard burn-barrels. Dioxin pollution is also affiliated with paper mills which use chlorine bleaching in their process and with the production of Polyvinyl Chloride (PVC) plastics and with the production of certain chlorinated chemicals (like many pesticides).
As indicated above, no one set out to create dioxin. As scientists and inventors set out to develop new materials and processes to further the lot of society, they created material and processes that begat not only increased production but increased hazards. By the time the hazards were uncovered, the economics of the new materials and processes had become entrenched and now, despite the fact the hazards have been clearly identified, it is very difficult to convince the economic powerbrokers to move away from the very things producing the identified hazards.

To satisfy the thirst of millions of residents plus meet the needs of the agricultural sector, the Oglalla Aquifer is being drawn down at non-sustainable rates. As reported last year by the Environmental News Service
There are some areas on the High Plains where water is being withdrawn from the Oglala aquifer at rates greater than the aquifer is being replenished. In these areas, the aquifer will not be able to sustain withdrawals at current rates in future decades, new research by the U.S. Geological Survey (USGS) has determined.

Underlying portions of eight states, including Colorado, Kansas, Nebraska, New Mexico, Oklahoma, South Dakota, and Texas, the massive High Plains aquifer, also called the Oglala aquifer, spans 173,000 square miles and provides irrigation and drinking water for one of the major agricultural regions in the world.

But USGS scientists have found a six percent decrease in the volume of water stored in the aquifer from the time groundwater pumping began in the 1940s to the year 2000.

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