BEIJING—Global stock markets slid Wednesday and oil prices surged more than $7 per barrel as Russian forces stepped up attacks on Ukrainian cities. Frankfurt, Shanghai, Tokyo, and Paris declined as President Vladimir Putin’s invasion fed fears of global economic turmoil. London opened higher. The war is adding to worries about global economic growth as the Federal Reserve and other central banks gear up to fight surging inflation by raising interest rates. “The conspiracy of geopolitical uncertainty and stagflation-type impulses is a brutal shock,” Tan Boon Heng of Mizuho Bank said in a report. Investors were waiting for more clues about possible rate hikes when Fed Chair Jerome Powell speaks Wednesday before Congress. In early trading, the DAX in Frankfurt fell 1.4 percent to 13,715.13 and the CAC 40 in Paris sank 1.2 percent to 6,322.17. The FTSE 100 in London gained 0.2 percent to 7,346.15. Russia’s central bank said stock …