Donna Laframboise discusses 18th century transportation issues, and particularly the horse manure problem:
The Superfreakonomics authors draw heavily on the work of Eric Morris, whose urban planning Masters thesis explored the reality of horse-based transportation in 19th-century cities. A user-friendly encapsulation of his research appears in an 8-page article here. (It was published in Access, a U of California transportation publication. The entire issue is available here.)
Morris points out that, by the late 1800s, large urban centers were “drowning in horse manure.” Not only were there no solutions in sight, people were making dire predictions:
In 1894, the Times of London estimated that by 1950 every street in the city would be buried nine feet deep in horse manure. One New York prognosticator of the 1890s concluded that by 1930 the horse droppings would rise to Manhattan’s third-story windows.
The automobile helped solve this growing ecological problem. Back in 2006, I had considered the same thing with a hypothetical blog post from 1870 which is pretty close to the Times of London article quoted above (which I had never seen):
As the US Population reaches toward the astronomical total of 40 million persons, we are reaching the limits of the number of people this earth can support. If one were to extrapolate current population growth rates, this country in a hundred years could have over 250 million people in it! Now of course, that figure is impossible – the farmland of this country couldn’t possibly support even half this number. But it is interesting to consider the environmental consequences.
Take the issue of transportation. Currently there are over 11 million horses in this country, the feeding and care of which constitute a significant part of our economy. A population of 250 million would imply the need for nearly 70 million horses in this country, and this is even before one considers the fact that "horse intensity", or the average number of horses per family, has been increasing steadily over the last several decades. It is not unreasonable, therefore, to assume that so many people might need 100 million horses to fulfill all their transportation needs. There is just no way this admittedly bountiful nation could support 100 million horses. The disposal of their manure alone would create an environmental problem of unprecedented magnitude.
Or, take the case of illuminant. As the population grows, the demand for illuminant should grow at least as quickly. However, whale catches and therefore whale oil supply has leveled off of late, such that many are talking about the "peak whale" phenomena, which refers to the theory that whale oil production may have already passed its peak. 250 million people would use up the entire supply of the world’s whales four or five times over, leaving none for poorer nations of the world
To the last point, my article on how John D. Rockefeller and Standard Oil saved the whales is here.