Climate change impacts are increasingly visible in South Asia (SA) with greater variability of the monsoon systems and wind pattern. Indo-Gangetic Basin (IGB), which is the food basket of South Asia, experienced weather extremes in one or other part of the region in every year and get affected the food security of almost all the south Asian countries. The increase in the occurrence of extreme weather events such as heat waves and intense precipitation that affect agricultural production drastically and thereby the food security and livelihoods of many small and marginal farmers, particularly in the more stress-prone regions of the central and eastern IGB. Under this scenario, Project Directorate for Farming Systems Research, which is one of the constituent Institute of Indian Council of Agricultural Research, India leads a SA AgMIP project entitled “Strengthening simulation approaches for understanding, projecting, and managing climate risks in stress-prone environments across the central and eastern Indo-Gangetic Basin”. The other partners are ICAR Complex for Northeast hill region, Barapani, India, Bangladesh Agricultural Research Council, Nepal Agricultural Research Council and CIMMYT-Nepal. Under this project we will be working the Integrated climate change assessment through linking crop simulation models with the economic modeling approach based on the AgMIP protocol at selected sites. During the fast track mode, we have selected wheat crop, APSIM model and Meerut District, Uttar Pradesh, India. The comparison of two crop simulation models DSSAT and APSIM for 76 farmers field data with 6 sites soil database. Preliminary results of TOA-MD fast track analysis of wheat show that there is about 10 percent reduction in yield under climate change scenarios (2040-69). Without adaptation, gains as a percentage of mean net farm returns are 24.53 percent while losses are 35.27 percent, and variability in net farm returns increases under climate change.