Climate change and food production: Pakistan M. Arif Goheer Global Change Impact Studies Centre (GCISC) Islamabad – Pakistan GECAFS IGP CPW&F and APN Launch Workshops Kathmandu-Nepal, June 27-30, 2006

Climate Change “the greatest challenge facing the world at the beginning of the century” World Economic Forum Davos, Switzerland 2000

Changing Climatic Trends Increasing concentration of CO2 in the atmosphere Pre-industrial revolution (1789) 280 ppm Present (2004) 380 ppm Expected level (2050) 550 ppm Rising surface temperatures Global Av. Temp. rise (20th century) 0.6 °C Projections for 2100 1.4 to 5.8 °C Changing rainfall patterns Source: IPCC, 2001

Depending on the level of GHG emissions and concentration in the atmosphere, the average global temperature would rise between 1.4 oC – 5.8 oC over the 21st Century

Climate and Food Production Weather and Climate are the key factors in food productivity Being open to vagaries of nature, food production are highly vulnerable to climate change phenomena

Climate Related Parameters of Agricultural Productivity CO2 Temperature Solar Radiation Precipitation Others (Wind speed and direction, Soil Moisture, Water vapour, etc.) Basic understanding of these factors helps manipulate plants to meet human needs of food, fiber and shelter The parameters also help understand impacts of climate change and devise adaptation/mitigation strategies

Climate-Water-Food Linkages Crop Water Demand Water Availability Evapo-transpiration (ET) Agriculture (Crop Yield) Photosynthetic Activity Canal/ground water GDD and Corresponding GSL

Projections of IPCC for South Asia Increase in surface temperature will contribute to snowmelt resulting in risk of floods Indus river inflows will decrease by 27% by the year 2050 Land degradation will cause land to shrink from present 0.8 ha per capita to 0.3 by 2010 Areas in mid and high latitudes will experience increase in crop yield whereas in lower latitudes will experience a general decrease, under elevated CO2 conditions IPCC, 2001

Semi-arid areas Crop models showed that increase in temperature of 0.9 and 1.8°C resulted in reduction in length of wheat growing season by 4 and 8 days respectively At 0.9°C increase in temperature, wheat grain yield increased by 2.5% whereas at 1.8°C increase, the grain yield decreased by 4% The increase in temp. would reduce the productivity of rice crop due to heat stress and reduction in growing season length

Arid areas Crop modeling studies showed a non significant trend in wheat yields under increased temperature scenarios (0.9°C and 1.8°C) Wheat straw yields were reduced by 7% and 12% with temperature increases of 0.9°C by 2020 and 1.8°C by 2050

Impacts on Food Production Due to Increasing Temperatures Shift in spatial crop boundaries will have enormous economic and social impact. e.g. Rice transplantation, Cotton picking etc. Increase/decrease in crop yields Rise in evapotranspiration rates, calling for greater efficiency of water use Shift in timing of developmental stages of pests in Crop-weed-pest relationships

Due to Change in Precipitation Pattern More dependency on ground water in the face of low precipitation danger of depletion of aquifer due to injudicious pumping increased cost of cultivation soil salinization due to poor quality ground water

Effect of water supplies Decreased Surface Water Supplies Reduction in yield and quality of crops due to water stress during critical growth stages Shift in cropping patterns Nitrogen volatilization losses from ammonical fertilizers

b) Increased Water Supplies Potential development of Water logging and Salinity/Sodicity Denitrification losses from ammonical and nitrate based fertilizers Shift in cropping patterns Increased incidence of plant diseases

Extreme Weather Events In addition to changing climate, increased variability in weather may occur with consequent frequent extreme events such as heat waves, droughts, wind storms and floods having negative impacts on agriculture

Pakistan’s Resource Base LAND (in million hectare) Geographical area = 79.6 Area under cultivation = 27.6% (21.87) Crop area irrigated = 22.6% (17.99) Rainfed Agriculture area = 4.97% (21.87) Forest = 4.5% (3.61) Culturable waste = 11.7% (9.31) Range Lands = 59% (46.96)

Cropping Seasons Rabi Kharif November-April May-October Wheat, Lentil, Chickpea Kharif May-October Rice, Maize, Mungbean, Cotton

Agricultural productivity Crop Yield Wheat 2262 kg/ha Rice 1836 kg/ha Maize 1768 kg/ha Sugarcane 48.1 t/ha Cotton 579 kg/ha Fodder 22.3 t/ha Agricultural Statistics of Pakistan 2001-02

Demand and Production projections with respect to climate change in Pakistan Commodities Baseline Requirement Demands (000 tonnes) Production 1995 2020 2050 Wheat 17.9 32.4 43.0 27.46 35.70 Rice 5.1 9.2 12.2 6.21 7.89 S.Cane 41.6 75.3 100.0 50.0 60.0 Cotton 1.8* 3.3* 4.4* 18.00* 25.0* Fruits 13.8 18.3 Vegetable 4.5 16.2 20.0 Meat 2.1 5.7 7.6 5.0 14.0 Milk 15.3 41.5 55.0 125 * Million Bales Source: CICERO 2000:2

Work Done at GCISC

Wheat & Rice Simulation Results using DSSAT based CERES-Wheat & CERES-Rice models Semi-arid areas Arid areas Humid area Sub-humid areas

Effect of Increase in Temperature and CO2levels on Wheat yields

Effect of Increase in Temperature CO2levels and Water Scenarios on Wheat yields

Effect of Increase in Temperature CO2levels and Water Scenarios on Wheat yields

Growing Season Length (Days) Effect of Increase in Temperature on Wheat GSL (DSSAT based results 1994-95 to 2003-04 for Cv. Inqalab sown on Nov. 20th) Temperature (°C) Growing Season Length (Days) Humid (Shangla) Sub Humid (Islamabad) Semi Arid (Faisalabad) Arid (Multan) Baseline 246 161 146 137 1 °C (increase over baseline) 232 155 140 132 2 °C 221 149 135 127 3 °C 211 144 130 123 4 °C 202 138 125 118 5 °C 194 133 121 113

Effect of Increase in Temperature and CO2levels on Rice yields in Semi-arid areas of Punjab Baseline Yield

Growing Season Length (Days) Effect of increase in Temperature on GSL of Rice in Semi arid areas of Punjab (Faisalabad) (Cv. Basmati Super transplanted in 1st Week of July) Temperature Growing Season Length (Days) Baseline 108 (increase over baseline) 1 °C 102 2 °C 100 3 °C 98 4 °C 92 5 °C 89

Conclusions Rise in CO2 level only has positive impact on wheat yield Rise in Temperature shows negative impact on wheat yield But it could be mitigated if CO2 level = 550 ppm Negative impact of Rise in Temperature on yield could also be mitigated by increasing number of Irrigations (but…) Reduction in water resources shows a negative impact on wheat yield Even 550 ppm CO2 level would not result in sustaining current yield level if water resources reduce Rise in CO2 levels could sustain the baseline Rice yields up to 1C

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