Dr S. Pasupalak*

Global climate change is now certain and occurrence of extreme weather events is a part of this climate change. As per the International Panel on Climate Change (IPCC), the climate change also includes climate variability.

The eastern Indian state of Odisha is vulnerable to such climate change. All the sectors of the state are vulnerable to climate change. Agriculture in the state is now experiencing adverse effects of delayed monsoon, increased frequency of heavy rainfall, prolonged summer, warming of kharif and rabi season, etc. The climate change will have tremendous impact on rice yield which could decrease by 577 kilogram [kg] per hectare [[ha] in 2020 compared to 2011.

Odisha University of Agriculture and Technology [OUAT] has determined effects of high temperature and elevated carbon dioxide on kharif rice crop. The earlier research results have shown that increase in temperature by 2oC was not so alarming to kharif rice productivity mainly due to beneficial effect of carbon dioxide fertilization in the atmosphere.

An attempt has been made to project the rice productivity scenarios in the state in the future climate of 2020, 2050 and 2080. As a pilot study, Swarna, the popular variety of state and Bhubaneswar weather were taken. Projected maximum temperature, minimum temperature and evapotranspiration during the rice season were determined under four scenarios of temperature increase by 2.6, 4.5, 6.0 and 8.5oC. Rice yields on the future climate were compared with the experimental yields of Swarna in 2011, which was considered as good kharif season for rice.

Projected Rice Growing Environment :

With conservative projected scenario 2.6, maximum temperature is likely to increase by 1.5oC in 2020 compared to 2011(Fig.1a-d). During the same period, the minimum temperature would rise by 0.9OC, kharif growing season rainfall would decrease by 134.7 mm while evapotranspiration of crop will increase by 211.7mm.

Under the moderate scenario of 4.5, rice growing environment would change little from 2.5 scenario. In 2080, the maximum temperature would increase by 2.2oC under 2.6 scenario and 4.4oC under 7.5 scenario. Minimum temperature would also increase considerably, as high as 4.2oC under 7.5 scenario in 2080 compared to 2011.

Projected Rice Yield :

Rice yield would approximately decrease by 577 kg/ha in 2020 compared to 2011. In 2080, the rice yield may further decrease by about 300 kg/ha. Such yield decrease will largely be due to accelerated anthesis and maturity. In 2080, maturity duration would decrease by more than two days.

To compensate the yield loss due to climate change, agronomic management has to change. This includes increased fertilizer application, efficient water use and stress tolerant varieties, among others.

• Dr S. Pasupalak is the Head of Department of Agricultural Meteorology, OUAT, Bhubaneswar