Oil is the world's most critical resource. Without it, nothing works in industrial civilization as currently configured. Few people dispute the idea … - James Howard Kunstler

We regarded opium as a godsend. It did not develop into an illicit trade, though. There was no legal prohibition, no police running around trying to suppress drugs, driving up the price artificially, and no marketing system. There were no distant markets to send it to because shipping anything was slow at best and often unreliable, and travel was something you just didn't do anymore. Anybody could grow their own poppies or buy raw opium paste from one of the growers. Farmers made more money growing raspberries or asparagus. They grew poppies as a public service. A few people took to smoking opium, but those with an extremely apathetic attitude toward survival tended not to last long in the new disposition of things.

The total planetary endowment of conventional nonrenewable liquid oil was… two trillion barrels before humans started using it [and possibly more, as most of it was used to protect the Earth's crust]. Since the mid-nineteenth century, the world has burned through... one trillion barrels of oil, ...representing the easiest-to-get, highest-quality liquids. [...] Oil has enabled the [post-War] population explosion [and also enabled the public-health and feminist revolutions].

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.