Black unemployment has historically been higher than white unemployment in the U.S. This gap was narrowing before the coronavirus pandemic. But with unemployment hitting record highs across the board, Black Americans could be left even further behind. Photo illustration: Carter McCall/WSJ The U.S. labor-market recovery is losing momentum as a surge in coronavirus cases triggers heightened employer uncertainty and consumer caution. Job openings in July are down from last month across the U.S., and Google searches for “file for unemployment” are creeping up. Growth in worker hours is waning at small businesses after several weeks of gains. The…