The Organization for Economic Cooperation and Development (OECD) released its growth forecast on Wednesday. The OECD downgraded its global growth outlook. The downgrade was largely driven by a slowdown in emerging market economies.

Global GDP is estimated to grow 3.0% in 2015 and 3.6% in 2016, down from 3.1% and from 3.8%.

"Global growth prospects have weakened slightly and the outlook is clouded by important uncertainties. Emerging economies have vulnerabilities that could be exposed by rising US interest rates and/or a sharper-than-expected slowdown in China, giving rise to financial and economic turbulence that could also exert a significant drag on advanced economies," OECD Chief Economist Catherine Mann said.

The OECD expect the U.S. will grow at 2.4% in 2015, up from the previous estimate of 2.0%, and at 2.6% in 2016, down from the previous estimate of 2.8%. The OECD said that the Fed will soon start to hike its interest rates, adding that the pace of the interest rate hike is more important than the timing.

Japan's economy is expected to grow at 0.6% in 2015 and at 1.2% in 2016, down from June estimate of 0.7% for 2015 and down 1.4% for 2016.

Eurozone's forecasts were upgraded to 1.6% in 2015 from the previous estimate of 1.4% and downgraded to 1.9% in 2016 from the previous estimate of 2.1%. OECD chief economist noted that the pace of recovery in the Eurozone was disappointing.

China is expected to expand at 6.7% in 2015, down from 6.8% estimate in June. Growth forecast for 2016 remained unchanged at 6.5%.

Mann pointed out that advanced and emerging countries should implement structural reforms "to encourage investment and reverse the slowdown in the growth potential output".