You've probably heard the claims that the Mayan calendar prophecies the end of the world in 2012 -- an idea that for some reason is tremendously appealing to modern-day apocalypse junkies, even though it's totally incorrect. Here's the 411: While December 21, 2012 corresponds to the end of a Mayan calendar cycle, the calendar calls for another cycle to begin immediately after that [source: Wolchover].
That said, there are some lesson from the Mayan collapse that we ignore at our own peril. Scientists worry that we are repeating the same pattern of deforestation that may have exacerbated climate change in Central America more than a millennium ago, except on a far more massive scale. Trees are about 50 percent carbon, and in the U.S alone, they presently absorb between 1 and 3 million metric tons (984,206 to 2,952,691 tons) of atmosphere-warming carbon dioxide, which offsets between 20 and 46 percent of what Americans spew into the atmosphere by burning coal and gasoline. But when we cut down trees or burn them, they release their stored carbon into the atmosphere, and they aren't around to absorb any more of it [source: Johnson].
Over the past several centuries, the U.S. has cut down about 90 percent of the forests that once covered the continent, and what remains is still in peril. In the Pacific Northwest, for example, about 80 percent of the old-growth forestland is slated for eventual logging [source: University of Michigan]. Worse yet, in nations in the developing world -- Latin America, the Caribbean, Africa, and Asia -- once-lush forests have been disappearing at an alarming rate, thanks to logging, agriculture, and need for living space. In recent years, there's been some international progress in slowing the rate of deforestation, but we still face the risk that it will push us even faster into climate chaos [source: Johnson]. It's a problem that we must work harder to solve.