東北タイにおける気候変動適応策としての天候インデックス保険の可能性

摘要

東北タイにおいて販売されている天候インデックス保険を対象として，保険金支払いのトリガーとなる インデックス値および農業被害が農家の世帯収入に及ぼす影響について評価した.東北タイ17県の3ヶ月 積算降水量と米生産量の関係から，米生産量は6-8月降水量と最も正の相関が高い県が多かったが，実際 に使用されている7-9月降水量を用いても相関は高くインデックス値は概ね妥当であると判断された.次 に，雨季米の生産量変動と米価格の推移から各県•各年における被害額を求め，農家世帯収入に及ぼす影 響を推定した結果，近年では被害割合は10%以下と小さかった.農家への世帯生計調査より，世带収入の 7割程度を農外収入が占めており農業収入の割合は比較的小さいこと，保険の適用頻度が5-10年に1回程度 であり支払いに対して懐疑的であることが天候インデックス保険普及の阻害要因と考えられた.%In northeast Thailand, the ratio of irrigated agricultural land was only 7.6% and others were rain-fed so that climate change makes agricultural production more unstable and also makes crucial damage to the societies and economics in rural area. To mitigate these issues, it is desirable to develop and disseminate enhanced adaptation systems. In this study, we focused on weather-index insurance for climate change adaptation measure. Firstly, we evaluated how affect the rainfall amount and patterns on rice production through regression analysis by using the meteorological and agricultural statistic data from 1985 until 2004. The production of wet season rice had positive relationship(R＞0.2, Slope＞0.2) with 3 month accumulated rainfall (Jun-Aug) in 11 province. As a result, employed rainfall index was suitable for accurate estimation of rice production in wet season. Secondly, household survey was conducted to grasp farmer's conditions of water use, cultivation, income balance. And then, economic loss by weather induced agricultural damage was estimated and impact on farmer's household income was evaluated by using the agricultural statistic and rice price data from 1981 until 2013. Recently, agricultural economic loss of around 600 million Baht was often occurred in northeast Thailand. However farmers household income was mostly rely on non-agricultural sector so that agricultural economic loss was less than 10% of their annual income. Current weather index was designed by 5-10 years return periods in many province and that also might be the one reason of obstacles of insurance sales.