Cong Zhentao — Global irrigation requirement under the scenario of sra1 b

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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.

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Cong Zhentao — Global irrigation requirement under the scenario of sra1 b

  1. 1. ICCCFS 2011 Global Irrigation Requirement  under the scenario of SRA1B Zhentaoi Cong1o, Jun Liul1, Tingju Zhu2 r E d t y u r s o g a n h e e1 Department of Hydraulic Engineering, Tsinghua University, China2 International Food Policy Research Institute
  2. 2. BackgroundIrrigation is by far the largest single user of water globally,accounting for approximately 70% of global water withdrawal and90% of global consumptive water use (FAO, 2011)Irrigated land accounts for no more than 20% of the worldscultivated land, but contributes about 40% of all agriculturalproduction and 60% of cereal production (FAO, 2011).Assessing irrigation water requirement under climate change isessential for understanding potential future water crisis and foodsecurity.Given the potential impacts of climate change on irrigation wateruses, estimating climate change impacts on irrigation waterrequirements is a critical step towards evaluating how muchwater will be needed for irrigation in the future (Döll, 2002).
  3. 3. FrameworkIPCC Scenarios + GCMs Rn, T, RH, u (monthly) FAO-Penman-Monteith ET0 – Reference Evapotranspiration SAGE FAO-Kc Crop water requirement ETc = Kc*ET0 Pe – Effective Precipitation Net Irrigation Requirement IR = ETc-Pe
  4. 4. 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. Rapid economic growth; Population peaks in mid‐century and declines thereafter; New SRA1B and more efficient technologies; Balanced energy sources. Heterogeneous world: Continuously increasing population;  Regionally oriented  SRA2  economic growth(more fragmented and slower). Convergent world: Same population as SRA1B; Rapid changes in economic  SRB1 structures(towards service and information); Reductions in material intensity; Clean and  resource‐efficient technologies. Baseline: 20C3M scenario, 1961-1990 Climate change scenario: SRA1B scenario, 2046-2065
  5. 5. IPCC Scenarios and GCMsScenarios Source: Figure 10.4 in Meehl, et al. (2007)
  6. 6. IPCC Scenarios and GCMs GCMs BCC‐CM1 ECHAM5/MPI‐OM1.125°×1.125° BCCR BCM2 MRI‐CGCM2.3.2 4°×3° CGCM3_1‐T47 AOM 4x3 NASA, USA 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 1.125°×1.125° Japan 4°×5° INMCM3.0 MIROC3.2‐MED INM 2.8125°×2.8125° IPSL‐CM4 HadCM3 Japan FGOALS1.0_g HadGEM1
  7. 7. Method to calculate ET0FAO Penman-Monteith equationWhere:– 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]
  8. 8. Change of ET0 5 GCMs MIROC3_2-HI BCM2 INMCM3 AOM MIROC3_2-MED
  9. 9. What caused the increasing of ET0 ? R RHThe change of ET0 is similar to Tthe air temperature in the future. U
  10. 10. Land useSAGE the Center for Sustainability And the Global Environment University of Wisconsin-Madison Global Land Use Database, 1992, 18 crops, 0.5°× 0.5° Wheat Maize Rice Cotton
  11. 11. Köppen climate classificationKc in FAO
  12. 12. Kc in FAO
  13. 13. Crop water requirementChange of ETc of all crop in 5 GCMs Change of ETc of maize in 5 GCMs Change of ETc of rice in 5 GCMs Change of ETc of wheat in 5 GCMs
  14. 14. Change of ETc 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%
  15. 15. Change of P 5 GCMs MIROC3_2-HI BCM2 INMCM3 AOM MIROC3_2-MED
  16. 16. 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%
  17. 17. Precipitation vs ETcEffective rainfall (USDA)Time step: 10 daysRandom Matching with the ETc
  18. 18. Change of Irrigation Requirement (IR) 5 GCMs MIROC3_2-HI BCM2 INMCM3 AOM MIROC3_2-MED
  19. 19. 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%
  20. 20. IR‐Irrigation RequirementETc China: ETc - increasing P - inceasing IR - not obviouslyP USA, Mediterranean area ETc - increasing P - deceasing IR - increasing obviouslyIR
  21. 21. Change of Irrigation Requirement (IR) Doll, 2002, Figure1(C), 2020, ECHAM4
  22. 22. Change of Irrigation Requirement (IR) Food production of countries, FAO Wheat Rice It is a big challenge for future world food security. Maize
  23. 23. Change of IR in China 5 GCMs MIROC3_2-HI BCM2 INMCM3 AOM MIROC3_2-MED
  24. 24. IR‐Irrigation RequirementChange of IR in SRA1B 2046-2065 with MIROC3.2_HI
  25. 25. ConclusionsTrends of ET0, ETc, P and IR under climate changes dependon different GCMs and different regions.ET0 and ETc would increase all over the world due to globalwarming.IR would significantly increase in the Mediterranean area andin USA due to the increase in ET0 and the decrease in P.
  26. 26. OutlookMore GCMs and RCM;Coupling the crop growth model and hydrological model topredict the irrigation requirement under climate changes;To consider the trend of precipitation frequency.
  27. 27. ICCCFS 2011 E d i t y o u r s l o g a n h e r e congzht@tsinghua.edu.cn

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