2012 is only said to be the end because of this reason:

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The largest solar flare.
You may say "This is nothing"
Solar flares emit radiation (or some other ray, I forgot) and that ray the solar flare emits interferes with radio waves.
"What are radio waves, and what uses them?"
Radio waves are part of the invisible spectrum, and play a major role in our society. Radio waves are used in: satellites, which means GPS's won't work. Cell phones use radio waves. Radio's use Radio Waves: Fun Fact: The Radio uses the frequency of a wave to determine the station. For example, 106.9 has a 106.9 frequency. 106.9 (some unit I forgot)/(per)s(second)Internet uses radio waves. Anything that needs a signal uses radio waves. Even TV. This means that the solar flare could cause all of this to go down.

[AK-47]

Uhhh, a solar EMP?

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Solar EMP?

[Fumetsu]

So? Humanity survived alot without all that. Society is way to spoiled on technology, we can always live differently.