TV talking heads and news headlines are heralding the fiscal cliff's danger to the U.S. economy. But a greater threat lies in wait thanks to the European debt crisis and slowing growth in China, says Harry Dent. The CEO and founder of HS Dent, a Tampa, Fla.-based economic research and forecasting firm, says we're on the brink of a "global meltdown" once the "debt bubble" explodes, regardless of what happens in Washington. He explains why this is