聖嬰現象對台灣氣候之影響與預測價值之估計

The Impacts of ENSO on Taiwan’s Climate and The Value of ENSO Forecast

溫室效應使得全球的氣候更加不穩定，而短期的聖嬰現象所導致的氣候變遷對農業經濟的影響已逐漸在擴大，如何將聖嬰預測的訊息適時的公佈，使得農民可以及時調整其生產決策以降低氣候變異之衝擊已經成為重要之研究課題。本研究將以台灣的稻米產業為例，來估計聖嬰預測對台灣稻米產業的潛在價值，進行之步驟有二，首先估計出聖嬰現象對台灣稻米產出的影響，接著將此影響帶入農業供需均衡模型中，並利用貝氏定理來求出聖嬰現象的預測價值。實証結果發現聖嬰年對中南部的一期稻作產出有正面的影響，影響的幅度在2.2%至8.3%左右，至於反聖嬰年與正常年對稻米一期與二期產出的影響則較無規則可循。其次，當聖嬰現象能被準確預測且農民能採取適當的因應措施時，全體社會的福利可增加2,451 百萬元，此即為聖嬰預測的潛在價值。

Global climate becomes unstable as green-house-gas emissioncontinues. Such climate changes have huge economic impacts onagriculture. The main purpose of this study is to estimate the value ofENSO forecast information on Taiwan’s rice industry. First, we estimatethe ENSO impacts on rice yield. The empirical results show that El Ninohas positive impacts, ranging from 2.2% to 8.3%, on rice yield at the firstproduction period in both central and southern regions. However, nosignificant change can be found in El Viejo and Neutral years. Second,a stochastic agricultural sector model is constructed to estimate the valueof ENSO information on rice based on the Bayesian theorem. We findthat if ENSO information is perfectly predicted and adopted by farmers toadjust their planting decisions, the value of such information is around2.45 NT billion.