Future of water and agriculture in Sri Lanka in the face of climate change, Nishadi & Vladimir...
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Water for a food-secure world
FUTURE OF WATER AND AGRICULTURE IN SRI LANKA IN THE FACE OF CLIMATE CHANGE
Nishadi Eriyagama & Vladimir Smakhtin (IWMI)
GWP Workshop on Climate Change Food and Water Security
Colombo, Sri Lanka, February 2011
Water for a food-secure world Water for a food-secure world
• Climate change signals in Sri Lanka – observed changes
• What will the future hold? – projected changes
• Impacts
– On water resources
– On agriculture
• Climate change vulnerability hotspots?
• Responding to climatic changes
• Knowledge gaps
OUTLINE
Food Security
Water for a food-secure world Water for a food-secure world
INFORMATION SOURCES
Sources
IWMI climate change vulnerability mapping
Over 75 national and global climate change studies
Interviews and e-mail correspondence with
-Government officials -International experts
16
Preliminary review of recent floods
Water for a food-secure world Water for a food-secure world
Dry Zone
Wet Zone
Intermediate Zone
Warming trends (0C/year) 1961-2000
OBSERVED CHANGES
Temperature
Source: Zubair et al. 2005
Anuradhapura 0.024-0.026
Badulla 0.022-0.024
Rainfall
No significant change in Mean Annual Rainfall Amount
South-West Monsoon (May – Sept): Stable (Yala)
North-East Monsoon (Dec – Feb): reduced & variability increased (Maha)
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PROJECTED CHANGES - 1
• General consensus: increasingly warmer in 21st century
• IPCC: stronger warming than the global mean in South Asia
• Projected magnitude of change: differs from study to study
Temperature
Source Model Scenario Base Year Change at end
21st century
Cruz et al.
2007
AOGCM A1F1, B1 1961-1990 + 2.93-5.44 0C
Kumar et al.
2006; Islam
and Rehman
2004
Regional
Climate
Model-RCM
A2, B2 1961-1990 + 2-4 0C
Basnayake et
al. 2004; De
Silva 2006
Statistical
Downscaling
of GCMs
A1F1, B1,
A2, B2
1961-1990 + 0.9-3 0C
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Lower Mean Annual Rainfall
Mean Annual Rainfall
Higher Mean Annual Rainfall
PROJECTED CHANGES - 2
Rainfall
Increased Variability Increased Floods & Droughts
- Projections for this century confusing and contradictory!
Higher South-West Monsoon R/F
Higher North-East Monsoon R/F
Higher South-West Monson R/F
Lower North-East Monson R/F
Kumar et al 2006; Islam and Rehman 2004; Basnayake et al. 2004; Basnayake and Vithanage 2004 a
Cruz et al. 2007; De Silva 2006; Basnayake and Vithanage 2004b
Lower South-West Monsoon R/F
Lower North-East Monsoon R/F
Ashfaq et al. 2009; Basnayake et al. 2004
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Dry Zone
Wet Zone
Intermediate Zone
Dry Zone
Wet Zone
Intermediate Zone
PROJECTED CHANGES - 3
Spatial Pattern of Rainfall Projections for 2050s
Projection 1 Projection 2
De Silva, 2006
De Silva 2006 Basnayake et al. 2004
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Dry Zone
Wet Zone
Intermediate Zone
Projection 3
De Silva, 2006
Punyawardane et al. 2010
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- -
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Ambiguity!
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IMPACTS ON WATER RESOURCES
• Dominant School of Thought: Gain in Mean Annual Water Availability
• But increased temporal and spatial variability
• Brunt of impact on north eastern and eastern dry zone: May become even drier!
• Increase in Soil Moisture Defecit in the Dry and Intermediate zones by 2050 (De Silva 2006): More irrigation?
• Lower water availability in the upper Mahaweli watershed by 2025 (Shantha & Jayasundera 2005): More power cuts?
Dry Zone
Wet Zone
Intermediate Zone
No comprehensive national study!
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Sea Level Rise: Inundation + Salt intrusion
40% of National GDP from coastal zone
IMPACTS ON AGRICULTURE
Paddy Tea Coconut
Yield:
• 0.1-0.5 0C temp increase:
1.2 to 5.9% reduction
(Vidanage &
Abeygunawardena 1994)
• Temp increase + CO2
increase: 24-39% increase
(De Costa et al. 2006)
Yield:
• 100 mm monthly R/F
reduction: 30-80 kg
reduction in ‘made’ tea/ha
• Increase in ambient CO2
concentration to 600 ppm:
33-37% increase
(Wijeratne et al. 2007)
Yield:
• Production after 2040:
not sufficient for local
consumption
•Increased pest and
disease problems -
reduce yield (Peiris et al.
2004)
Irrigation Requirement:
13-23% increase in Maha by
2050 (De Silva 2006)
Spatial Impact:
• Cultivations at low and
mid elevations more
vulnerable (Wijeratne et
al. 2007)
Economy:
Losses in the range $32 -
$73 million (Fernando et.
al 2007)
Economy: Rs. -11 billion to Rs. +39 billion by 2100 (Seo et. Al. 2005)
Water for a food-secure world Water for a food-secure world
CLIMATE CHANGE VULNERABILITY HOTSPOTS-1
Climate Change Vulnerability Index
Anuradhapura
Nuwara-Eliya
Ratnapura Sensitivity Index
Exposure Index
Adaptive Capacity Index
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CLIMATE CHANGE VULNERABILITY HOTSPOTS -2
Exposure Index based on: Frequency of exposure to historical droughts, floods, cyclones
Sensitivity Index based on: Population density, % employed in agriculture, irrigation water availability, agricultural diversity (crops diversity, livestock farming, fishing)
Adaptive Capacity Index based on: education level, poverty incidence, level of infrastructure development
0 – lowest vulnerability 100 – highest vulnerability
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CLIMATE CHANGE VULNERABILITY HOTSPOTS -3
Anuradhapura
Nuwara-Eliya
Ratnapura
Highly vulnerable areas are:
• Typical farming areas
• Have low socioeconomic and infrastructural assets (low adaptive capacity)
• Show high levels of exposure to historical climate extremes
• Primary food producing areas - rely heavily on
water availability for agriculture
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Response
Mitigation Adaptation
Research
Knowledge
RESPONDING TO CLIMATIC CHANGES - 1
•Signatory to UNFCC and Kyoto Protocol
•Second National Communication prepared
•Small hydropower CDM projects
•Others – “Green Lanka” program
•National Adaptation Strategy
•“No Regrets” interventions
Eg: Restoration of the ancient tank system
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Adaptation
RESPONDING TO CLIMATIC CHANGES - 2
Crops
•Development of heat/salt/pest resistant short term crop varieties by 6 research institutes. eg. Rice Research and Development Institute (RRDI)
•Crop diversification, change of planting time and location
Climate Tools
•Predicting annual national coconut production
•Predicting seasonal water availability within the Mahaweli scheme
Water Resources
•Restoring existing tanks
•Developing sustainable groundwater
•Rainwater harvesting and storage
•Use of micro-irrigation
•Wastewater reuse
•Greater shift towards alternative energy from hydropower
Sea Level Rise
•Climate Change Adaptation Action Plan by Coast Conservation Department (CCD)
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• Detailed and quality controlled climate scenarios
• Flood and drought forecasting systems
• National Water Resources Audit eg. Prototype web tool by IWMI
• Comprehensive national study on vulnerability of water resources and agriculture to climate change covering:
– Both surface and ground water
– Water quantity and quality
– Combined impact of enhanced CO2 + temperature + increased/decreased rainfall on agriculture
• Central agency to cater to the need for corporation and data sharing
KNOWLEDGE GAPS
http://idistest.iwmi.org:8080/slwa/
Water for a food-secure world Water for a food-secure world
THANK YOU !
ACKNOWLEDGEMENTS: • Mr. Lalith Chandrapala, National Disaster Mitigation Council (NDMC) • Dr. B. V. R. Punyawardane, Department of Agriculture • Ms. Dharshanie De Silva, World Bank • Ms. Chandanie Panditharatne, Ministry of Environment and Natural Resources • Mr. Sarath Premalal, Department of Meteorology • Mr. Bandula Wickramarachchi, Coast Conservation Department (CCD) • Mr. N. Wickramaratne, Mahaweli Authority • Mr. H. M. Jayatillake, Irrigation Department • Mr. K. A. U. S., Imbulana, Ministry of Irrigation • Mr. L. Manawadu, University of Colombo • Dr. W. M. W. Weerakoon, Rice Research and Development Institute (RRDI) • Ms. Karin Fernando, Centre for Poverty Analysis (CEPA) • Dr. G. G. A. Godaliyadda, Irrigation Department • Dr. A. W. Jayawardena, Public Works Research Institute, Japan • Mr. Gerard Fernando, National Water Supply and Drainage Board • Mr. Harsha Sooriyarachchi, Water Resources Board • Staff of Sri Lanka Association for the advancement of Science (SLASS) • Dr. Herath Manthrithilake (IWMI)
Water for a food-secure world Water for a food-secure world
0
500000
1000000
1500000
2000000
2500000
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19
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Number Affected Damage (000 US$)
Source: "EM-DAT: The OFDA/CRED International Disaster Database
Top ten Natural Disasters from 1901 to 2000Number Affected