cong zhentao — global irrigation requirement under the scenario of sra1 b
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DESCRIPTION
The Chinese Academy of Agricultural Sciences (CAAS) and the International Food Policy Research Institute (IFPRI) jointly hosted the International Conference on Climate Change and Food Security (ICCCFS) November 6-8, 2011 in Beijing, China. This conference provided a forum for leading international scientists and young researchers to present their latest research findings, exchange their research ideas, and share their experiences in the field of climate change and food security. The event included technical sessions, poster sessions, and social events. The conference results and recommendations were presented at the global climate talks in Durban, South Africa during an official side event on December 1.TRANSCRIPT
E d i t y o u r s l o g a n h e r e
1 Department of Hydraulic Engineering, Tsinghua University, China2 International Food Policy Research Institute
Global Irrigation Requirement under the scenario of SRA1B
Zhentao Cong1, Jun Liu1, Tingju Zhu2
ICCCFS2011
Background
Irrigation is by far the largest single user of water globally, accounting for approximately 70% of global water withdrawal and 90% of global consumptive water use (FAO, 2011)Irrigated land accounts for no more than 20% of the world's cultivated land, but contributes about 40% of all agricultural production and 60% of cereal production (FAO, 2011). Assessing irrigation water requirement under climate change is essential for understanding potential future water crisis and food security. Given the potential impacts of climate change on irrigation water uses, estimating climate change impacts on irrigation water requirements is a critical step towards evaluating how much water will be needed for irrigation in the future (Döll, 2002).
Framework
Rn, T, RH, u (monthly)
ET0 – Reference Evapotranspiration
Crop water requirement ETc = Kc*ET0
FAO-Penman-Monteith
FAO-KcSAGE
Net Irrigation RequirementIR = ETc-Pe
Pe – Effective Precipitation
IPCC Scenarios + GCMs
IPCC Scenarios and GCMs
Scenarios1PTO2X CO2 concentration increase 1% /year, until DOUBLE; constant thereafter.
1PTO4X CO2 concentration increase 1%/year, until QUADRUPLE; constant thereafter.
20C3M Greenhouse gasses increasing as observed through the 20th century.
COMMIT Atmospheric burdens of long‐lived greenhouse gasses are held fixed at AD2000 levels.
PICTL Constant pre‐industrial levels of greenhouse gasses.
SRA1BRapid economic growth; Population peaks in mid‐century and declines thereafter; New and more efficient technologies; Balanced energy sources.
SRA2 Heterogeneous world: Continuously increasing population; Regionally oriented economic growth(more fragmented and slower).
SRB1Convergent world: Same population as SRA1B; Rapid changes in economic structures(towards service and information); Reductions in material intensity; Clean and resource‐efficient technologies.
Baseline: 20C3M scenario, 1961-1990Climate change scenario: SRA1B scenario, 2046-2065
IPCC Scenarios and GCMs
Scenarios
Source: Figure 10.4 in Meehl, et al. (2007)
IPCC Scenarios and GCMs
GCMsBCC‐CM1 ECHAM5/MPI‐OM
BCM2 MRI‐CGCM2.3.2
CGCM3_1‐T47 AOM 4x3
CGCM3_1‐T63 GISS ModelE‐H
CNRM‐CM3 GISS ModelE‐R
ECHO‐G CCSM3
CSIRO Mark 3.0 PCM
CM2.0 ‐ AOGCM MIROC3.2‐HI
INMCM3.0 MIROC3.2‐MED
IPSL‐CM4 HadCM3
FGOALS1.0_g HadGEM1
1.125°×1.125°Japan
2.8125°×2.8125°Japan
4°×3°NASA, USA
1.125°×1.125°BCCR
4°×5°INM
Method to calculate ET0
FAO Penman-Monteith equation
Where:– ET0 : reference evapotranspiration [mm day-1]– T : mean daily air temperature [°C]– Rn : net radiation [MJ m-2 day-1]– G : soil heat flux density [MJ m-2 day-1]– es : saturation vapor pressure [kPa]– ea : actual vapor pressure [kPa]– Δ : slope of temperature-pressure curve [kPa °C-1]– γ : psychrometric constant [kPa °C-1]– u: wind speed [m/s]
5 GCMs MIROC3_2-HI
BCM2 INMCM3
AOM MIROC3_2-MED
Change of ET0
R
RH
T
U
The change of ET0 is similar to the air temperature in the future.
What caused the increasing of ET0 ?
SAGEthe Center for Sustainability And the Global EnvironmentUniversity of Wisconsin-MadisonGlobal Land Use Database, 1992, 18 crops, 0.5°× 0.5°
Land use
Wheat
Rice
Maize
Cotton
Kc in FAOKöppen climate classification
Kc in FAO
Crop water requirement
Change of ETc of all crop in 5 GCMs
Change of ETc of rice in 5 GCMs
Change of ETc of maize in 5 GCMs
Change of ETc of wheat in 5 GCMs
Region MIROC3_2‐HI BCM2 INMCM3 AOM MIROC3_2‐MED
China +4.9% +2.6% +7.8% +4.7% +5.4%
USA +12.6% +8.8% +13.6% +4.9% +14.7%
India +4.4% +1.9% +1.2% +1.6% ‐3.2%
Australia +12.4% +6.5% +8.9% +6.8% +5.4%
Europe +10.9% +6.7% +8.8% +3.7% +17.9%
Russia +8.5% +4.6% +9.7% +0.5% +8.7%
Global +8.6% +5.2% +7.7% +4.4% +7.5%
Change of ETc
5 GCMs MIROC3_2-HI
BCM2 INMCM3
AOM MIROC3_2-MED
Change of P
Region MIROC3_2‐HI BCM2 INMCM3 AOM MIROC3_2‐MED
China +12.1% +5.0% +4.3% +1.8% +6.6%
USA ‐2.5% ‐2.2% ‐5.0% +5.8% ‐11.3%
India +3.7% +9.4% +13.0% +11.4% +14.5%
Australia ‐2.0% +4.1% ‐7.1% ‐9.9% +7.6%
Europe +5.8% ‐0.8% ‐0.7% +0.5% +4.4%
Russia +13.0% +4.4% +8.4% +8.1% +10.5%
Global +3.1% +1.6% +1.8% +3.7% +3.0%
Change of P
Effective rainfall (USDA)
Time step: 10 days Random Matching with the ETc
Precipitation vs ETc
5 GCMs MIROC3_2-HI
BCM2 INMCM3
AOM MIROC3_2-MED
Change of Irrigation Requirement (IR)
Region MIROC3_2‐HI BCM2 INMCM3 AOM MIROC3_2‐MED
China +3.7% +0.6% +10.1% +1.4% +5.7%
USA +30.6% +23.4% +27.9% +6.4% +33.6%
India +12.8% ‐1.1% ‐5.7% ‐1.6% ‐10.5%
Australia +15.0% +3.5% +8.3% +7.8% +1.9%
Europe +11.2% +17.1% +22.0% +13.9% +31.3%
Russia +6.2% +12.9% +22.7% +3.8% +5.8%
Global +14.8% +8.5% +11.6% +5.0% +12.1%
Change of Irrigation Requirement (IR)
ETc
P
IR
China:
ETc - increasing
P - inceasing
IR - not obviously
USA, Mediterranean area
ETc - increasing
P - deceasing
IR - increasing obviously
IR‐Irrigation Requirement
Change of Irrigation Requirement (IR)
Doll, 2002, Figure1(C), 2020, ECHAM4
Change of Irrigation Requirement (IR)
Wheat
Rice
Maize
Food production of countries, FAO
It is a big challenge for future world food security.
Change of IR in China
5 GCMs MIROC3_2-HI
BCM2 INMCM3
AOM MIROC3_2-MED
IR‐Irrigation Requirement
Change of IR in SRA1B 2046-2065 with MIROC3.2_HI
Conclusions
Trends of ET0, ETc, P and IR under climate changes depend on different GCMs and different regions.
ET0 and ETc would increase all over the world due to global warming.
IR would significantly increase in the Mediterranean area and in USA due to the increase in ET0 and the decrease in P.
Outlook
More GCMs and RCM;
Coupling the crop growth model and hydrological model to predict the irrigation requirement under climate changes;
To consider the trend of precipitation frequency.