Download Climate change and food production: Pakistan (Arif Goheer)

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
Climate
Temperature
Rainfall
Wind,
Sunshine,
Solar Radiation
CO2 level
GDD
and Corresponding GSL
Evapo-transpiration (ET)
Crop Water Demand
Canal/ground
water
Water Availability
Agriculture (Crop Yield)
Photosynthetic
Activity
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 Cropweed-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
a) 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
• November-April
• 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
(000 tonnes)
1995
2020
2050
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
5.1
13.8
18.3
50.0
60.0
Vegetable
4.5
12.2
16.2
20.0
50.0
Meat
2.1
5.7
7.6
5.0
14.0
Milk
15.3
41.5
55.0
50.0
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
Semi-arid Areas
360
360
550
5000
4000
Yield (kg/ha)
Yield (kg/ha)
Arid Areas
3000
2000
1000
0
550
5000
4000
3000
2000
1000
0
1
2
3
4
1
5
2
3
4
5
Change in Temperature (°C)
Change in Temperature (°C)
Subhumid Areas
3500
3000
Yield (Kg/ha)
Yield (Kg/ha)
Humid Areas
4500
4000
3500
2500
3000
2500
2000
1500
2000
1500
1000
1000
500
0
500
1˚C
2˚C
3˚C
4˚C
Change in temperature (°C)
5˚C
0
1˚C
2˚C
3˚C
4˚C
Change in temperature (°C)
5˚C
Effect of Increase in Temperature CO2levels and Water Scenarios
on Wheat yields
Semi Arid Areas
Yield (kg/ha)
5000
4000
3000
2000
1000
0
1
2
3
4
5
Tem perature Increase (°C)
4irri_360ppm
4irri_550ppm
2 irri_360ppm
2 irri_550ppm
Effect of Increase in Temperature CO2levels and Water Scenarios
on Wheat yields
Arid Areas
Yield (kg/ha)
4000
3000
2000
1000
0
1
2
3
4
5
Tem perature Increase (°C)
4irri_360ppm
4irri_550ppm
2 irri_360ppm
2 irri_550ppm
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
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
(increase over baseline)
Effect of Increase in Temperature and CO2levels on Rice yields
in Semi-arid areas of Punjab
Baseline Yield
5000
4500
Yield (kg/ha)
4000
3500
3000
2500
2000
1500
1000
500
0
1°C
2°C
375ppm
3°C
Temperature
4°C
550 ppm
5°C
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)
102
1 °C
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