By Juveria Tabassum (Reuters) -Starbucks faces challenges in reviving its business, CEO Brian Niccol said on Tuesday, after the coffee giant posted disappointing global comparable sales and profit with inflation and economic uncertainty driving up costs and dampening U.

Starbucks (SBUX) reported second quarter earnings Tuesday that came in below Wall Street estimates as new CEO Brian Niccol's attempts to turn around the coffee giant. US comparable store sales — a closely watched metric that includes results only from stores open for more than a year — fell for the fifth-consecutive quarter,

Shares of Starbucks have fallen 8% this year, as investors worry about tariffs and how they will affect consumer spending.