"Black Swans" are history-changing events that are nearly unpredictable. Europeans believed that all swans are white; when it was discovered that there where indeed black swans in some Austrailian territories, it simply forced a change in thinking that had been entirely unexpected.
Naturally, the discovery of the existence of europeans did not particularly disturb the swans, but the aboriginal groups of Oceana and much of the rest of the colonial world where somewhat suprised, particularly when they believed that the horizon was the edge of the world. The arrival of the first anglo-saxon explorers would generally be a black swan event.
The sudden outbreak of the first world war now seems obvious, but the sudden coallecense of mechanized warfare, tactics, and the collapse of the treaties that held Europe up was at the time unprecedented. Indeed, there are a number of historical examples of dark Black Swans, ones that herald catastrophy and conflict. Before the turn of the century, most United States citizens considered terrorism to be a distant problem; Noone could predict the effect that nuclear weapons would have on the global community. The Hindenburg disaster, Chernoble, and the Black Plauge, are all Black Swans. But Black Swans are not always strictly bad; the popularization of the printing press, for instance, and the end of the cold war, man walking on the moon.
Indeed, most of our cherished inventions where Black Swans, in particular because they did things in new and unexpected ways. One of the more recent Black Swan inventions would be communication networks, or put simply, the internet.
Most Black Swans are neither good nor bad, or otherwise still so obscure in effect and total reach that we are still not sure how it will end up. The massive popularization of the Automobile, for instance, drove the transformation of the daily lives of perhaps the majority of humanity.
We may be upcoming upon new Black Swans as we speak; Though it seems predictable now, obviously noone at BP predicted that the Deepwater Horizon well could self-destruct as it has. It's massive, truamatic impact has yet to be fully comprehended, and may change the way the public thinks about ecological safety thuroughly and deeply.
By it's very definition, no one could reasonably predict the effects that a Black Swan could have, but they are not always beyond total comprehension. It is thus possible to guess what form our next Black Swan could take, but it's of little use beyond idle speculation. Since this is an internet forum we're basically here for idle speculation, however.
Of course, there are a few obvious Swans that can quite possibly occur:
- Thermonuclear War
- Major Catastrophic Climate Change
- Similar to above, high-level volcanic event such as a "supervolcano" or asteroid impact.
- Proof of extra-terrestrial life
- Proof of extra-terrestrial intelegence
- Proof of non-human terrestrial intelegence
- Artificial intelegence
- Sudden Economic collapse
- Invention of controlled fusion with net energy gain.
- Conventional "world" war, most likely involving China, India, Pakistan, and much of the mideast, possibly over the resources present in Myanmarr, and potential for limited US involvement.
- Manned landing on non-terrestrial planet such as Mars
- Large-scale industrialization of space
- New physical laws discovered with practical application (easy teleportation, new energy sources, transmutation of elements)
- Application of known laws in unexpected ways (practical space elevator, similar orbital development using new launch methods, popularization of miniturized production plants)
Of course, there are others. One of my favorites of this less-popular class are:
- Cultural shift away from conventional technology (In other words, end of techie "fad" as new people refuse to buy mp3 players, computers for use other than as tools, and otherwise less gadget-intensive life-styles.)