Primary factors contributing to increases in global food prices, based on a four-crop price index (wheat, rice, corn and soybean). a) Shows the change in crop prices (green line) for the period 2002‒2011, and identifies long-term and short-term factors that contributed to price changes over time. Tighter supply-demand balances (as depicted by global stock-to-use ratio “S:U ratio”) and economic growth/recession, for example, are a backdrop to weather events and trade policies. b) Change in crop prices between May 2010 and April 2011 in relation to weather-related events that resulted in supply shortfalls. Both wet and dry conditions, which were not isolated to one global region, contributed to a reduction in global crop supply.
Adapted from Trostle, 2011.