Evidence from 2022–2023 shows that fertilizer- and acreage‑related stress on global food production did in fact persist at unusually high levels for roughly the 9–18 months after April 2022, broadly matching Friedberg’s timing.

• Fertilizer prices and use: Fertilizer prices spiked further after Russia’s invasion of Ukraine, then by March 2023 had only fallen back to pre‑invasion levels while still remaining above 2021, with significant uncertainty; high costs led farmers to cut fertilizer use and shift acreage away from more fertilizer‑intensive crops such as corn and wheat in 2022. (ers.usda.gov) Global data from the International Fertilizer Association show fertilizer use falling about 3% in 2021 and 5% in 2022, with especially sharp cuts (≥10%) in regions like West and Central Europe, West Asia, and Africa—consistent with the “reduced acreage and fertilizer use” mechanism he described. (world-grain.com)

• Food prices and inflation: The FAO Food Price Index peaked in March 2022, then declined but was still around 121 points in August 2023—more than 20 points above 2020 levels—indicating that global food commodity prices remained elevated through mid‑to‑late 2023 despite coming down from the peak. (fao-test.atmire.com) FAO also reports that food consumer price inflation rose to about 13.5% globally by December 2022 and was still around 9.3% in July 2023, far above pre‑pandemic norms, showing that the stress on consumers persisted into his forecast window. (fao-test.atmire.com)

• Food‑security outcomes: The 2023 State of Food Security and Nutrition in the World and related analyses report that about 2.4 billion people were moderately or severely food insecure in 2022—391 million more than in 2019—with hunger and food insecurity remaining far above pre‑COVID levels. (web.wtocenter.org.tw) The Global Report on Food Crises 2023 finds 258 million people in 58 countries in acute food insecurity in 2022, the highest number in the report’s history, with very high levels still projected for 2023. (web.wtocenter.org.tw) These impacts are explicitly linked to the combination of war‑driven fertilizer disruptions, reduced fertilizer use, and other shocks.

• Duration relative to his 9–18‑month window: Country‑level modeling (e.g., for Rwanda) expected high global fertilizer prices and associated reductions in fertilizer use and agricultural growth to last through at least 2024, with particularly strong effects in 2022–2023. (knowledge4policy.ec.europa.eu) At the same time, by late 2024 the World Bank reported that fertilizer prices had finally fallen about 17% year‑over‑year and were projected to keep easing, suggesting that the most acute phase of fertilizer‑driven stress was concentrated in the roughly 2022–2023 period Friedberg pointed to, rather than becoming a permanently escalating crisis. (blogs.worldbank.org)

Taken together, the data show a prolonged, fertilizer‑ and acreage‑related squeeze on global food production and supply that remained severe well into 2023, broadly in line with Friedberg’s forecast of a 9–18‑month "slow train" crisis after April 2022. While some indicators (like the FAO price index) began easing before the very end of that window, overall conditions remained materially worse than pre‑crisis for about the duration he predicted, so the prediction is best classified as right rather than wrong or merely ambiguous.