Do food imports increase the variability of domestic food prices? The answer to this question depends on whether foreign production is more volatile than domestic production. If imports are likely to destabilize domestic prices, storing crops for future consumption may prove an appealing strategy to cope with the adverse supply effects of a more unstable climate. Unfortunately, public storage has proven to be unsustainable due to the high costs of carrying crop inventories over time and the inability of policy planners to correctly forecast changes in domestic supply. Therefore, understanding the roles of imports and stocks on domestic food price instability is important as domestic shortfalls in food production are likely to become more frequent as the world's climate becomes warmer. Using maize prices observed in 76 maize markets of 27 maize net importers across Africa, Asia and Latin America during 2000-2015, we find that, on average, a 1% increase in the ratio of imports to total consumption is correlated with a 0.29% reduction of the intra-annual coefficient of variation of maize prices; likewise a 1% increase in the amount of maize available in stocks at the beginning of the season is correlated with a 0.22% reduction in the said coefficient. We also find that climate-induced supply shocks toward mid-century may increase maize price variability in the focus countries by around 10%; these increases could be offset with similar increases in the ratio of imports to total consumption or in the stock-to-use ratio at the beginning of the crop marketing year. The fact that both imports and stocks help to stabilize domestic prices suggests that their uses should hinge on a careful cost-benefit analysis, including the risk of facing world production more variable than domestic production and the costs of carrying maize inventories over time.

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In 2016, the U.S. launched a trade dispute against China at the World Trade Organization, arguing that China has been restricting its grain imports via tariff quota administration. Despite sharp criticisms by the U.S., the extent to which the grain imports were restricted in China remains largely unknown, primarily due to that China's grain import behaviors are still under‐researched. The U.S. grain export sector might actually gain little from China's grain trade liberalization in the short run, since China has become less import dependent on the U.S. through the pursuit of import diversification. In this context, this article aims to quantify impacts of the tariff quota administration on China's grain imports from its trading partners. We calculate ad valorem tariff equivalents of the tariff quota administration and then estimate import demand elasticities using a source differentiated import demand model. We find that the tariff quota administration might have reduced China's quota fill rates for the grain commodities by 10–35% during 2013–2017. In particular, the U.S. wheat exports to China were largely negatively affected. We also find that the tariff quota administration in China acts like a variable import levy—its import restrictiveness varies negatively with world prices, leading to lower import demand elasticities.

International trade helps to smooth food price swings caused from seasonal imbalances between domestic supply and demand. Trade also increases the possibility of importing price volatility from abroad. This concern looms large in the face of increased crop yield variability associated with climate change. We assess the extent to which maize yield shocks in exporting countries exacerbate the intra-seasonal variability of maize prices in a cross section of 75 markets in Africa, Asia, and Latin American countries during 2000-2018. We find that extreme below-trend reductions in maize yields in exporting countries are associated with increased intra-annual maize price variability in the focus countries. In contrast, above-trend maize yields in exporting countries are associated with reduced variability.