It is probably because of what is happening in the Middle east. The Middle East is a tinderbox. The economies in the Unites States, in Europe and in other places are slowing down too, so there are many reasons (for this global sell off).
(iShares MSCI Emerging Markets Index ETF (EEM), SPDR S&P 500 ETF Trust (SPY), Market Vector Russia ETF Trust (RSX), SPDR Dow Jones Industrial Average ETF (DIA))
Jim Rogers is a legendary investor that co-founded the Quantum Fund and retired at age thirty-seven. He is the author of several investing books and also a renowned financial commentator worldwide famous for his contrarian views on financial markets.