The document summarizes factors contributing to increased volatility in global markets in September 2015, including the potential for the Federal Reserve to raise interest rates. While the US economy has improved, global risks from China's economic slowdown and falling commodity prices pose challenges. It is unlikely the Federal Reserve will raise rates in September due to this increased turbulence, though a rate hike by the end of 2015 or in 2016 is still possible depending on how the global situation evolves.