Effect of probable increase in carbon dioxide and temperature on wheat yields in India

Effect of increase in carbon dioxide and temperature on growth, development, water use and grain yield of wheat was simulated for several locations of India using a dynamic crop growth simulation model, WTGROWS. Long term average weather data and average soil properties for various agro-ecological zones were input in the model. The effect of climate change on productivity was dependent upon the magnitude of temperature change. At 425ppm CO2 and no rise in temperature, grain yield at all levels of production increased significantly. In northern India, a 1°C rise in mean temperature had no significant effect on potential yields but irrigated and rainfed yields increased in most places. An increase of 2°C in temperature reduced potential grain yields at most places. The effect on irrigated and rainfed productivity varied with location. The natural climatic variability also had considerable effect on the magnitude of response to climate change. Evapotranspiration was reduced in irrigated as well as rainfed environments. The responses to climate change were closely related to the effects of increased temperature on crop duration