London—President Donald Trump’s unpredictable tariff policy and countermeasures by America’s trading partners will likely deal a heavy blow to economies worldwide, with US prosperity hit particularly hard, the International Monetary Fund warned Tuesday. Global economic growth will slow to 2.8% this year, from 3.3% last year and significantly below the historical average, the IMF forecast in its World Economic Outlook. The slowdown expected in the United States is even steeper, with its economy likely to grow only 1.8% in 2025, compared with a 2.8% expansion in 2024. Both predictions are more pessimistic than the fund’s January projections, which came before Trump’s flurry of tariff announcements took America’s average import tax to its highest level in a century. …North America, just like all regions, can’t expect any upside from the tariffs further down the line. “The long-term impact of the tariffs, if they are maintained, (will be) negative for all regions, just like the short-term impacts,” Gourinchas said.