By the mid-1920s, the great wave of immigration suddenly ended. The National Origins Act of 1924 and other measures set new highly restrictive immigr… - James Howard Kunstler

The germ theory, which emerged in the late nineteenth century, focused the world's attention on the specific agents responsible for... diseases, but the [physical,] social and ecological contexts are equally important [for it], and these are now coming more prominently into play with world population well beyond the limits of the earth's [sic] [...] [optimum] carrying capacity and with climate change... in progress. [...] Ecological... [pressures], rapid changes in land use, penetration of formerly inaccessible habitats, and disturbed migration routes can lead to the appearance or diffusion of a disease. While we may be able to identify [some, if not all] the microorganisms involved, we can be helpless in the face of it, and our behavior may still promote its spread.

In America, after the crash of 1929, the loss of faith in various forms of credit represented by abstract instruments of finance translated into a persistent lack of money—that is, a means of exchange— and the institutions devised to create it stood in disrepute. People could buy very little. Business stagnated. Companies would not hire workers when there was so little demand for products. It was a vicious cycle and it had vicious side effects. Another way of looking at the financial debacle of the 1930s is an ecological view such as ’s metaphor of the industrial economy as a “detritus ecosystem.”
Catton argues that the human race living off the “drawdown” of nonrenewable fossil fuel resources is the equivalent of the algae in a pond enjoying a temporary rush of nutrients in one brief season. Catton’s analogy can be applied and extended to clarify the Great Depression in the context of ecological economics. After the crash of 1929, something… definitely changed in America. But the puzzling part is that the “nutrients in the form of cheap oil—the plenty” Roosevelt spoke of—still flowed. So why did the economic environment become so intractably unhealthy? From an ecological view, the Great Depression represented the effects of severe socioeconomic pollution” produced by the oil-fueled boom of the 1920s, and this “pollution” had the effect of “poisoning the financial ecosystem and consequently killing off financial “organs” that people had come to depend on in order to “thrive” (i.e., to grow wealthy and reproduce). Specifically, the “pollution” killed off the organs that generated credit and turned it into money. This systemic “pollution” of the financial ecosystem harmed the industrial environment enough to temporarily quash any further exuberant “growth.” There was no human die-off but there was a die-off of expectations and a reduction in [the] carrying capacity of the U.S. economy.
Is it fair to say that the by-product of zealous oil use literally converts into such an abstract form of "pollution" capable of poisoning what amounts to a social consensus? This must return us to the idea of entropy. Entropy is the spending down of energy and its translation into negative by-products. […] Air pollution is one expression of entropy. But so is social disorder. So is [the] institutional breakdown. Bodily death is another. These negative by-products of entropy can become interchangeable as entropy progresses, depending on any combination of variable conditions and circumstances. A careful reading of twentieth-century history would bear this out. In the modern era, entropy has been expressed in conditions as seemingly unrelated as war, industrial pollution, pornography, mass political murder, the shattering of a consensus about the value of money, and incompetent parenting. The introduction of high entropy into a given system is profoundly destabilizing in many ways.

Oil and gas were generally so cheap and plentiful throughout the twentieth century that even those in the lowest ranks of the social order enjoyed its benefits—electrified homes, cars, televisions, [and] air conditioning. Oil is an amazing substance. It stores a tremendous amount of energy per weight and volume. It is easy to transport. It stores easily at regular air temperature in unpressurized metal tanks, and it can sit there indefinitely without degrading. You can pump it through a pipe, you can send it all over the world in ships, you can haul it around in trains, cars, and trucks, [and] you can even fly it in tanker planes and refuel other airplanes in flight. It is flammable but has proven to be safe to handle with a modest amount of care by people with double-digit IQs. It can be refined by straightforward distillation into many grades of fuel—gasoline, diesel, kerosene, aviation fuel, heating oil—and into innumerable useful products—plastics, paints, pharmaceuticals, fabrics, [and] lubricants.
Nothing really matches oil for power, versatility, transportability, or ease of storage. It is all these things, plus it has been cheap and plentiful. […] The lack of these qualities is among the problems with the putative alternative fuels proposed for the post-cheap-energy era. Cheap, abundant, versatile. Oil led the human race to a threshold of nearly godlike power to transform the world. It was right there in the ground, easy to get. We used it as if there was no tomorrow. Now there may not be one. That's how special oil has been.