According to the , sea levels rose by ten to twenty centimeters during the twentieth century and are currently rising by about two millimeters a year… - James Howard Kunstler

As hunger and hardship increase, the world may see more than one wave of more than one disease. If and when an influenza pandemic emerges, for instance, many AIDS sufferers will succumb, but people infected with the AIDS precursor, HIV, will still survive influenza and AIDS will march on. India, for example, was among the hardest-hit nations in the 1918 flu pandemic. Today it has among the highest rates of AIDS infection. The age-old human enemies, tuberculosis, malaria, cholera, streptococcus, and other members of the familiar gang will be on hand with new immunity to the old techno-tricks of the [nineteenth and] twentieth centur[ies]. Even after these diseases may have spent themselves for a while, climate change [which in turn could create new diseases] will still be with us. Nobody really knows where that is taking us, though we do know that the human race has endured more than one ice age in the past.

[Everything, and not just] all human enterprise can tend toward diminishing returns and unsustainability, but some modes have far more long-term prospects than others and some are socially suicidal, even in the short term. Many civilizations, from the Sumerians to the Maya, have faltered when overinvestments in the scale and complexity of food production produced ruinous diminishing returns. On American farms in the early 1800s, the balance between calories expended and calories produced as [the] food was about even. This occurred as tools reached a high stage of refinement but before machines replaced human labor and traditional knowledge. It implies a distinction between tools and machines, between work done with tools and work done by machines. Production improved while entropy was kept to a minimum. Under the current industrial farming system, it takes sixteen calories of “input” to produce one calorie of grain, and seventy calories of input to produce one calorie of meat. A hundred years ago, just before the introduction of… fossil fuel-based technologies, more than 30 percent of the American population was engaged in farming. Now the figure is 1.6 percent. The issue is not moral, academic, or aesthetic. […] It’s a matter of those ratios being made possible only because cheap oil and automation made up for so much human labor. We did what we did in the twentieth century because we could. Of course, not all farm labor amounts to slavery or serfdom. Depending on how farming is organized, it can result in a very satisfactory way of life and rewarding social relations. Agriculture in the United States was organized very differently in Pennsylvania and South Carolina 150 years ago, and not simply because of climatic differences.
Farmers had quickly become addicted to a new debt system of annual operation, mortgaging their farms to raise cash to pay for new machinery and fertilizer—literally betting the farm on a good crop. With prices chronically depressed, mortgages could not be paid off. Farm foreclosures soared in the mid-1920s. Another unanticipated consequence of mechanized farming was the destruction of [the] soil. The tractor and its implements were machines that no one had previously experienced before, and it was some time before farmers noticed the insidious effects of soil compaction, rutting, and erosion that occurred. This would combine a few years later with an extended drought to produce the additional hardship of the .

We can conclude that the Earth is a fickle place for all life, not least the human project of civilization. We maintain a most uncertain toehold in our narrow niche of comfort here, with a vast community of other living things on a planet that might have a self-regulating life of its own. I’m not altogether convinced by the Gaia theory, but there’s plenty of reason to believe in a form of cosmic equilibrium that amounts to rough justice. There are consequences for our doings, and when we cross the frontier into the realm of too much magic cosmic judgment may come thundering through our little lives like what our distant ancestors thought of as the wrath of God.