The U.S. economy seems to be humming along – at the moment, but threats from a global slow down and trade war loom.

According to CNN, Federal Reserve Chairman Jerome Powell on Wednesday reported a healthy U.S. job market and rising incomes, but he warned of “noteworthy risks” that threaten future growth.

“In particular, sluggish growth abroad and trade developments have weighed on the economy and pose ongoing risks,” Powell said in prepared remarks for testimony before the Joint Economic Committee.

“During the hearing, Powell restated his position that negative interest rates would not be appropriate for the US economy…He also highlighted the risk of central banks having less room to rescue the US economy in a downturn given historically lower interest rates.”

“In the past, the Fed has been able to cut its benchmark rate by around 5 percentage points, but with the federal funds rate hovering a little above 1.5% Powell noted, “We don’t have that kind of room.” “