Uncertainty of Climate Change Impacts To answer the second objective of the study, this study investigates the implication for greenhouse warming on Thailand's agriculture by employing our estimated coefficients in equation (5) together with future climate projections during 2040-2049 simulated by PRECIS (Providing REgional Climates for Impacts Studies) regional climate model and used Global Circulation Model (GCM) ECHAM4 dataset as initial data for calculation. The simulation covers IPCC emission scenarios A2 and 823, which could account for the upper and lower limit of climate change impact! on Thailand's agriculture.