This study analyzes the economic impacts of crop productivity change that will be caused by global climate change. It is also investigated whether liberalizing crop trade will exacerbate or offset the losses from climate change. Applying the PEP-w-1 global CGE model using the GTAP 8 DB shows that most of the welfare effects are generated by the change in crop productivity, and trade liberalization plays very limited role as far as the change in world GDP is concerned. However, it is also found that trade liberalization affects welfare in several regions where their protection rates are high. Moreover, crop production and self-sufficiency in each region are substantially affected by trade liberalization even if welfare in the region is affected very little because of product substitution.