11 Disruptive Events That Could Alter Earth's Future

Think tanks and futurists call them "Disruptive Event" - events on a scale so global and so cataclysmic, they have the potential to irrevocably alters the future of humanity. 

Do the people who run our world have contingency plans for these, I wonder?  Since the U.S. government doesn't even have a contingency plan for a big snowstorm, as this past winter just proved, I have my doubts! 

1. Asteroid Strike.  Scientists estimate an asteroid a mere 10km in diameter was responsible for the destruction of 70% of species inhabiting the Earth at that time (including those lovable dinosaurs).   The good news is that we now have the smart folks at NORAD scanning the skies for potential threats; and researchers from federal labs actively have been brainstorming ideas for ways to deal with this type of  extraterrestrial threat.
2. Plague. Apparently it's not going to be swine flu that takes us out, but one thing the swine flu outbreak did teach us is that we are still a long way from ensuring we have effective containment plans that account for the realities of the world today, including illegal immigration and air travel. Isn't it comforting to know that we're basically one genetic mutation away from annihilation?
3. Climate change.  The effects on humanity would be dramatic enough (near-term, think starvation, civil unrest, and property destruction; long-term, expect massive global population shifts) - but that doesn't even begin to contemplate the impact on flora and fauna, which don't have the adaptability of humans, creating the potential for massive species extinction. 
4. Nuclear War.  As anyone who'se watched a Godzilla movie knows, it isn't necessarily the bomb that kills you: it's the radiation it leaves in its wake that renders the environment unstable (aka nuclear winter), land uninhabitable, and DNA unstable.  Assuming some nations survive the apocalypse, prepare for global civil unrest, environmental disaster, and roaming zombie hoards.
5. Volcanic Eruption.  Geologists believe a massive volcanic eruption may have been the cause of the "Great Permian Extinction," the greatest mass extinction in Earth's history.  It's not the eruption that kills you; it's the decades of perpetual twilight and buildup of greenhouses gases caused by the quantities of ash flung into the atmosphere that ultimately leads to extinction.  People with solar powered homes should expect to be eaten first.
6. Genetic Modification/Cloning.  It took nature several millions of years of experimentation to come up with DNA sequences capable of producing living creatures.  Alas, we humans don't have that kind of patience - it's likely we won't fully comprehend the consequences of our genetic tinkering until it's too late to undo whatever it is we've done.  It's possible that these impacts may be positive, enabling humanity to eliminate disease and create new food and energy sources.  It's also possible that genetic modification may wreak havoc by creating fatal superviruses, undermining the human immune system, or fundamentally recalibrating the value we place upon life. (Repeat after me: "Soylent Green is people!")
7. Artificial Intelligence. It's only a matter of time before AI becomes capable of genuine cognitive independence.  After that, Darwin's theory of evolution suggests that AI will turn its attention towards perpetuating its own survival.  Are we ready to coexist with a species smarter than we are? I have my doubts.
8. Energy Crisis. Whoever controls the energy, wins. The end.
9. Natural Disaster That Destroys a Major Country/City.  The nature of the disaster (earthquake, flooding, tsunami, tornado, megastorm) doesn't matter.  What matters is that, as 9/11 and the recent economic recession have taught us, the people of the world are - for better or worse - irrevocably interconnected, and a disaster striking any significant appendage of that body threatens the political, financial and social survival of the rest of the body.
10. Cyberwarfare. One minute you're googling "funny babies" - the next, it's a world-wide power outage that never ends.  All the wealth stored in the form of stocks, bonds and other financial constructs, destroyed.  Virtually all transportation and communication systems, unusable.  Safety features at water purification plants, nuclear power plants, prisons, and dams, disabled.  You may want to start now on your list of stores to loot first. 
11. Alien Encounter.  Doesn't have to be an invasion a la "Independence Day" - basically, any encounter with intelligent life forms is going to irrevocably alter humanity's future.  Let's hope the folks at Area 51 are ready.