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Scientists have discovered how weather and yield affect the world wheat trade


University of Maryland scientists (USA) have found that countries with large differences in extreme weather conditions and synchronous yield changes are generally trading partners and with higher wheat trade volumes. These results underscore the need to improve the existing international trade network, taking into account the patterns of extreme weather stress and the synchronicity of yields between countries.

Extreme weather events such as drought, floods and abnormal heat threaten food security on a regional to global scale as food availability, availability and appropriate use have declined sharply. Between 2003 and 2013, extreme weather events caused significant damage amounting to 30 billion US-Dollar in agricultural productivity. Crop production was the most affected: the decline in yields led to price fluctuations in food systems, affecting food trade, farmers' welfare and economic development, especially in low-income or import-dependent countries.

For example, the abnormal heat of 2010 in Russia led to restrictions wheat exports, led to wheat shortages and price spikes in the Middle East, where more than a third of wheat shipments went to Russia, and possibly contributed to destabilizing the region.

Simultaneous declines in the yields of major exporters can disrupt the global trade network and food supply, and synchronous fluctuations in yields between trading partner countries can further exacerbate the problem. Thus, the conflicting role of international trade in solving the food security problem is linked to extreme weather events and yield variability, but such associations remain poorly studied and require thorough investigation.

The scientists' analysis showed that two factors — the magnitude of extreme weather stress and the synchronicity of yield fluctuations — significantly affect the international wheat trading network. Pairs of countries with a larger difference in thermal load are more likely to have trade relationships and higher trade volumes. Meanwhile, in the existing wheat trading network, trading partnerships are more likely to be established between countries with synchronized yield fluctuations. This poses a systemic risk in the current global wheat market, as a synchronized crop failure can disrupt wheat supplies and aggravate the lack of food security for both partner countries.

Other fundamental drivers in the analysis (e.g. production levels, economic and geopolitical factors) show a significant link to trade relationships and volumes, further reaffirming their importance in the international trade network. The scientists' findings demonstrate the need to account for extreme weather stress and yield synchronicity within the framework of trade policy in order to increase the stability and equity of the global food system.

International trade in agricultural crops could potentially mitigate the negative impact of extreme weather events on food security by exporting food from regions in surplus to regions in deficit.

Source: Agronovosti (Russian)

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