If someone asked you at 9 a.m. on the morning of 10 September, 2001, when you thought the World Trade Centers in NYC might collapse, what would your answer be?

If they were to ask you 24 hours later, would that answer have changed?

If someone were to ask you where major earthquakes were likely to occur, might you be able to do so?

If the were to ask you when, within even decadal precision, could you?

Complex systems are ... complex. Major state changes may occur suddenly and with little warning, but also relatively unpredictably.

There's a widely-held misconception that science is specifically predictive or is based on laboratory experiments. Neither are true. Science is based on empirical observation and systemic theories, generally arriving at a causal understanding of phenomena. In the case of many complex systems, there's a long history of classification and ontology preceding a deep theoretical understanding. In specific cases such as biology and geology, scientific study existed for centuries before a core theory developed. The theory of evolution in biology, for example, does little to predict what forms of species will come to exist, but Darwin and Wallace's work, based on observation, did make several specific predictions which were subsequently born out:

- That organisms are subject to continous change and variance, and that "species" (the term has a philosophical meaning long predating its biological one) are not fixed and constant, but change, emerge, differentiate, and die out, over time.

- That there is a selective pressure exerted by the environment.

- That there is some mechanism for storing and transferring genetic information over generations, providing genetic inheritance. Darwin and Wallace's work predated notions of genes, genomes, or DNA and RNA. The general characteristics of those phenomena were, however, predicted by and consistent with the underlying theory.

The specific predictions of evolution are not generally time-based, but describe conditions and mechanism. There is some back-casting prediction based on genetic and molecular clocks which permits dating genomes roughly based on the differences which have accumulated. There is not much by way of future predictions, though we can generally presume that these will evolve in a fitness landscape (or more recently, "seascape" --- a landscape which is constantly changing itself).

Geology didn't arrive at its core principle officially until the late 1960s: plate tectonics. (I've discussed this several times elswhere on HN.)

What a complexity and systems-based analysis does provide is a framework for analysing the past and identifying patterns and correlations.

We know that the previously forecast global mass famine didn't occur, and can identify reasons why it did not: better cultivation techniques, cultivars, fertilisers, pest control, irrigation, harvesting, transportation, processing, preservation.

We can look at those factors and consider what happens if or as these are reversed. There are correlations between, for example, natural gas prices and crop yields: higher gas prices -> higher fertiliser prices -> lower fertiliser use -> lower crop yields.

Similarly, I'd expect weather disruptions (heat, drought, freezes, storms) to have measurable impacts, and unstable weather to be a factor. A major secular change (sharp global warming, sea-level rise and salt-water intrusion, major volcanic event, asteroid impact, solar variance) could have devastating global impacts, whether for a few years or millennia. The historical record shows instances of each.

A major crop disease affecting staples (maize, rice, wheat) could be immensely disruptive, especially if it crosses national borders. This is the scenario which concerns me most, especially as populations and their pathogens tend to co-evolve. See Kyle Harper's The Fate of Rome, which refers to human pathogens, though my sense is that our agricultural foundations, both plant and animal, are even more vulnerable.

Civil disruption and wars in major exporting regions (as presently in UA/RU) can and do have major effects. So do economic disruptions reducing purchasing power in food-precarious markets. This was a major factor precipitating the Arab Spring / Green Revolutions. It's a factor that's watched closely by global organisations such as the UN and Nato, as this has a huge impact on regional instability and migrations.

Transportation disruptions, through, say, higher fuel prices, piracy, or naval conflicts at major shipping choke points (Straits of Malacca, Gulf of Aden, Suez Canal, Bosperous, Gibralter, South China Sea) can also have a huge impact.

And as tolerances and surpluses shrink, the system is ever more susceptible to major shocks.

In the case of the WTC, what changed the prediction horizon was a major exogenous shock. In the case of the global food system, I'd suggest similarly looking at crop yield trends, purchasing power amongst the poorest states, climatic patterns, disease trends, and the like. Most likely what we'll see are a growing number of regional famines, spreading both in area and up global income levels.

The last major famines were in the early 1970s in Bangladesh. If you're old enough to recall Live Aid and starvation in Ethiopia in the 1980s ... that was mild by comparison. The list of major famines through history is sobering, particularly that there were several during the 20th century.

https://en.wikipedia.org/wiki/List_of_famines

Historically, famines reducing populations by 10--90% within affected regions were common. A huge factor in these was the inability to either transport large stocks of grain long distances quickly or cheaply (effectively impossible until the 19th century), or to have early warning that such shipments might be required. Much current famine-avoidance occurs through global crop arbitrage. Countries which have traditionally had large agricultural surpluses (notably the United States) no longer do to nearly the extent they had a half century ago, despite advances in overall crop yields.

So, no, a precise schedule is difficult to provide. The locations and conditions under which circumstances might become rapidly perilous, however, are predictable, noted above, similar to seismic, tsunami, and climate or natural disaster risks.