𝑆𝐼𝑦 𝑑𝑆𝐼𝑦 = 100 ( − 1) 𝑆𝐼1979−2006 3. Change in current year rainfall volatility relative to long run volatility in 1979-2006: 𝑑𝐶𝑉𝑦 = 100 ( 𝐶𝑉1|𝑦 𝐶𝑉28|1979−2006 − 1) 4. Change in maximum/minimum temperature in current year compared to long run average in 1979-2006: 2006 1 𝑑𝑇𝑀𝐴𝑋𝑦 = max(𝑇𝑀𝐴𝑋) − ∑ max(𝑇𝑀𝐴𝑋) 𝑦 𝑖 28 𝑖=1979 2006 1 𝑑𝑇𝑀𝐼𝑁𝑦 = min(𝑇𝑀𝐼𝑁) − ∑ min(𝑇𝑀𝐼𝑁) 𝑦 𝑖 28 𝑖=1979 Where max(𝑇𝑀𝐴𝑋) and min(𝑇𝑀𝐴𝑋) are maximum and minimum temperature at year i, 𝑖 𝑖 respectively. Estimation The final model specification varies according to the underlying trend in each dataset. Hence, the choice of level or form of measurement is essential in coming up with the final model. Take, for example, the climatology measures, including each of the climate variables without transformation is taken generally as assuming that the relationship between income from agriculture and say change in rainfall is linear. In this subsection, the objective is to establish the fact that the relationship is non-linear and interpretation of the trend will be deferred until the specific datasets since there are other explanatory variables. CBMS-FAO | 26