Global warming is likely to impact productivity of buffaloes due to their sensitivity to temperature changes. Air temperature, humidity, wind velocity and solar radiation are the main climate variables that affect buffalo production in tropical climate. In the present study sensitivity of lactating Murrah buffaloes to sudden temperature (Tmax, Tmin) change and THI have been analyzed from milk production and climatic records (1994-2004) of Karnal. Algorithms were developed and validated on lactating buffaloes during 2005-2006 at the Institute. A sudden change (rise or fall) in Maximum/Minimum temperature during summer and winter was observed to affect milk production. The decline in minimum temperature (>3°C) during winter and increase (>4°C) during summer than normal were observed to negatively impact milk production upto 30% on the next or subsequent days after extreme event. The return to normal milk production depended on severity and time period of thermal stress/ event occurrence. The R2 was very low for cool period observed during Feb- April/Sept-Nov and actual effect on milk production was minimum. This indicated that low THI had a relatively small effect on milk production performance. The lactation period of animals are shortened during extreme summer when THI were more than 80 and reproductive functions were also adversely affected. Thermal stressed buffaloes did not exhibit estrus or exhibited estrus for short period. The potential direct effects of possible climate change and global warming on summer season milk production of Murrah buffaloes were evaluated using widely known global circulation model UKMO to represent possible scenarios of future climate. Both milk production and reproductive functions of Murrah buffaloes are likely to be affected due to warming effects.