It's clear that urban sprawl has far reaching consequences, and it certainly has an adverse influence on environmental health. As of now, humans have not experienced particularily severe repercussions as a result of this practice. However, as the amount of agricultural land and animal habitat decreases, our troubles will likely multiply.
The fact remains that we have a rapidly growing population, and the only humane solution is to maintain this rate of growth, and continue to offer dwellings to all. If we cannot achieve this through urban sprawl, what other options do we have?
Some people say the solution is to develop vertically rather than horizontally, in order to save the terrestrial resources. However, we do not as of yet possess the technology to make this feasible on a significant scale. Substantial improvements to exisiting infrastructure would be required in order to reliably deliver power and water, as well as to prevent collasal traffic jams.
Others go one step further and suggest that instead of separate residences, places of work, governmental and recreational facilities, we build cities-within-cities, or super-dense, self-contained metropolises housed within skyscrapers. At the present, "archologies" are far from feasible. We could produce certain goods on site, but the vast majority of resources would have to be shipped in. Also, there are major health risks to living in such close confinement, as well as the risks of pollution and crime. We don't like to be fenced in, and even with all the material pleasures in the world available to residents, it's likely people would start to go bonkers.
Still others propose that we should try and develop our homes in barren areas so that we do not destroy areas rich in flora and fauna and areas containing arable soil. However, you still have to ship all the resources a consumer demands to that area. As of now, it is more viable to build a city in an area rich in natural resources such as San Francisco or Seattle than to choose a wasteland such as the area surrounding Las Vegas. Once again, we presently lack economical and efficient ways of transporting water, power, food and consumer goods over long distances. With increases in technology, it will also become possible to produce such things in more locations. But, we are not there yet.
So, we see that urban sprawl is inevitible for the near future. There is still plenty of usable land in California and other states across the US. We will continue to develop it until we see direct and significant consequences. This is just something that we must accept in a capitalist society. To our minds, the short-term economic costs of placing a localized moritorium on new construction and relocation will override the long-term environmental damage.
About all we can do is to continue to provide wildlife refuges and allow for greenbelts in our city planning. We can also work for more environmentally friendly transportation and construction. But, the cost must be reasonable. Far too often, we clear-cut the areas in which we develop subdivisions without replanting anything more than froufrou plants and shrubs simply because it's cheap. But, it really doesn't cost that much to line the streets with trees like they did prior to the 1950s. If we cannot stop environmental sprawl, we can at least make efforts to lessen it's impact.
Frankly, the bigger issue here is human overpopulation and its influence on the environment. We can reduce our per-capita emission of VOCs and the like, but can it keep pace with the growth rate of our population?? In general, it cannot.
So, we better hope that we continue to develop technology to deal with these problems, because we are doomed to self-destruction otherwise.