Modelling climate change impact on crop evapotranspiration

Global warming and climate change and its impact on crop water requirement are a major concern of this century. It has been established that the regional and global temperature is rising due to increased concentration of green house gases in the atmosphere. Rising temperature is expected to affect the crop water requirement. This study was undertaken to evaluate the trend and predict the changes in climate parameters, and assess the impact of climate change on crop water requirement using local weather data. Auto Regressive Integrated Moving Average (ARIMA) model was used for forecasting the future climate trend. Assessment of impact of climate change on crop water requirement was done for different climate change scenarios. Scenarios considered for assessment were based on ARIMA, Indian Network for Climate Change Assessment (INCCA) and Inter-Governmental Panel for Climate Change (IPCC) predictions. Crop water requirement of various crops would decrease by 7.5 to 14.2 mm by 2030s if it is determined using all important climatic parameters. Increase in water requirement varied from 13 to 77.5 mm for rice and 7.2 to 43.5 mm for pearl millet depending on the scenarios. Results indicate that crop water requirement did not increase if it was estimated using all important climatic parameters even though the average temperature increased during this period. However, if only rise in temperature is considered, crop water requirement would increase under all scenarios considered in this study.