El Niño, La Niña, and world coffee price dynamics
研究厄尔尼诺南方涛动（ENSO）事件对世界咖啡价格的短期影响，使用1989年3月至2010年12月的月度数据和平滑转换自回归模型，发现ENSO确实对咖啡价格有短期冲击，对咖啡生产者和市场中介有参考价值。
Abstract Coffee is produced in equatorial and subequatorial regions of the world, which are also most affected by El Niño Southern Oscillation (ENSO). ENSO events have a tendency to amplify weather conditions such as droughts or excess precipitation in the affected regions, resulting in production shortage or excess supply, subsequently impacting agricultural commodity prices. In this research we assess effects of ENSO events on world coffee price dynamics using the monthly data between March 1989 and December 2010. We employ smooth transition autoregression framework to examine nonlinear dynamics of ENSO and coffee prices, and illustrate the results of this research using generalized impulse‐response functions. We find that ENSO events indeed have short‐term impacts on coffee prices. The research findings are of interest to coffee producers and intermediaries in the coffee markets as well as researchers in the fields of environmental and development economics.