2012 is not y2k, y2k is a misunderstandment of technology. 2012 is the doomsday predicted by the mayans, (For the life of me I can't remember his name...), and several Native American Tribes, and various cultures around the world. Okay so not too specific in that but it's so widespread in when it was predicted and recurring predictions since that makes it stand out so much.
Anyways as a quick list, here are the ways the world has been predicted to end by Science:
YellowStone- biggest volcano to erupt that could cover the entire world in soot and block the sun out for over ten years, basically Like venus for ten years. Not to mention Canda, U.S. and Mexico are dodging flaming balls of rock and a large portion of all three is being taken out by lava and earthquakes.
Magnetic Shift: Geologists predict it to happen, not if but when in the next few years (2012) or in the next 100,000 years. This would cause all computers to fry and anything else electronic, so basically end of the world due to anarchy and chaos. There is a computer under development that runs on light and not electrical components, but it's completion is in 2013, and public release 2018. Full integration of it would take another decade.
There are tons more but I'm only going to say one more, Massive Solar Storm. Oh it's just what, solar energy and it happens all the time right? Well it looks as if a massive one could be building up and remember the magnetic shift I told you about? Well same EMP effect. Anarchy and Chaos follow as well. :3