Commodity price uncertainty comovement: Does it matter for global economic growth?

We investigate the macroeconomic effects of commodity price uncertainty by explicitly accounting for comovement across commodity markets. Using quarterly realized volatilities of major agricultural, metals, and energy commodity prices, we estimate a hierarchical dynamic factor model that decomposes uncertainty into a global component, common to all commodities, and group-specific components capturing sectoral uncertainty. The estimated uncertainty factors are then embedded into country-specific Structural VAR models to assess the dynamic macroeconomic responses to uncertainty shocks through impulse response functions. We focus in particular on business investment and exports across a panel of advanced and emerging economies. Our results show that a global commodity price uncertainty shock generates sizable and persistent recessionary effects on investment and trade worldwide. Benchmark comparisons indicate that this global commodity uncertainty shock produces larger and more persistent macroeconomic contractions than standard uncertainty measures. Importantly, we show that, once global uncertainty is accounted for, commodity-specific uncertainty shocks exhibit differentiated effects. Increases in agricultural and metals price uncertainty lead to contractionary outcomes, whereas energy-specific uncertainty shocks generate positive short-run responses in investment and exports. These findings provide new empirical evidence that oil price uncertainty can be expansionary when it reflects sector-specific dynamics rather than global demand uncertainty. Overall, our framework offers a novel way to disentangle "bad" and "good" commodity price uncertainty.