Starbucks released its fourth-quarter earnings early on Tuesday.Spencer Platt/GettyStarbucks pre-released its earnings on Tuesday.The surprise release showed sales dropped in its key markets of the US and China.CEO Brian Niccol said he's planning a broader turnaround of the coffee chain.Starbucks sprung a surprise on investors on Tuesday and posted its earnings early — and the figures show that new CEO Brian Niccol has an uphill battle ahead.The company said comparable sales fell 7% for the fourth quarter, including a 6% slump at its US stores.