Predictions about the year 2012 do not necessarily involve catastrophe. The idea that 2012 is meaningful stems primarily from Mayan astrology and its associated calendar, the Mesoamerican Long Count calendar. Whereas the Gregorian and Julian calendar systems repeat days and months ad infinitum, the Mesoamerican system involves cycles of approximately 5,125 years each. After 5,125 years, the calendar is re-set. The year 2012 marks the end of one such cycle.
So, where does the idea of catastrophe figure in? The Mayan's main religious text, the Popol Vuh, states that humankind is currently in its fourth cycle. The gods will create a new world on December 21, 2012, a winter solstice.
So-called Western peoples, possibly predisposed by a literal interpretation of the Bible, associate the Mayan belief with Armageddon. However, even as this religious belief may sound apocalyptic, it needn't be. A new world could be akin to another Age of Enlightenment, or a time when humankind interacts more sustainably with the natural environment. Some New Age scholars emphasize that one calculation for the beginning of the Age of Aquarius - a time of harmony - is the year 2012.
It's most likely that, like overblown Y2K predictions, prophesies about the year 2012 will be unmet. At the same time, it's hard to deny the symbolism of ushering in a new world at this time in human history.