PARIS—The main risk to an otherwise upbeat global economic outlook is that the current inflation spike proves longer and rises further than currently expected, the OECD said on Wednesday. Global growth is set to hit 5.6 percent this year before moderating to 4.5 percent in 2022 and 3.2 percent in 2023, the Organisation for Economic Cooperation and Development said in its latest economic outlook. That was little changed from a previous forecast of 5.7 percent for 2021, while the forecast for 2022 was unchanged. The OECD did not produce estimates for 2023 until now. With the global economy rebounding strongly, companies are struggling to meet a post-pandemic snap-back in customer demand, causing inflation to shoot up worldwide as bottlenecks have emerged in global supply chains. Like most policymakers, the OECD said that the spike was expected to be transitory and fade as demand and production returned to normal. “The main …