164
models where mean temperatures in the growing season ranged from 15 to 32 °C
with artificial heating. Their results indicated that rise in temperature decreased
grain yield in the majority of wheat growing locations. Average yields for the periods between 1981 and 2010 decreased; ranging between 1% and 28% across 30
sites under increase in temperature by 2 °C. Furthermore, yield losses rose to
between 6% and 55% for a temperature of 4 °C. They also predicted that global
wheat production will fall by 6% for each 1 °C of further temperature increase.
Eyshi Rezaei and Bannayan (2012) studied rain fed wheat yield using the HadCM3
climate change model under the A2 scenario and using DSSAT crop simulation
model. They reported a yield reduction by 50% in the 2040–2069 periods. In another
simulation study in Mexico, Hernandez-Ochoa et al. (2018) projected a general
decline in wheat yields by the 2050s. They also stated that despite the growthstimulating effect of elevated CO 2 concentrations, consistent yield declines were
simulated across most of the main wheat growing regions of Mexico due to the
projected increase in temperature. They added that national wheat production of
Mexico is projected to decline between 6.9% for RCP4.5 and 7.9% for RCP8.5
climate change scenarios.
Using A2 and B2 climate change scenarios developed from HadCM3 model,
Khalil et al. (2009) and Moneir, (2012) found that for wheat planted in clay soil and
surface irrigation, yield losses will occur namely 33–36% and 31–35%, respectively
in both investigations. Whereas, for wheat grown in silty clay soil and under sprinkler system, yield losses were 39% and 34% under A2 and B2 climate change scenarios, respectively (Noreldin et al. 2012). In salt affected soil and under surface
irrigation, wheat yield losses under farmer irrigation practice were high, namely
47% and 44% under A2 and B2 climate change scenarios, respectively (Ouda et al.
2012). Similarly, for farmer irrigation practice in sandy soil and under sprinkler
irrigation, yield losses were 32% and 27% under A2 and B2 climate change scenarios, respectively (Ouda et al. 2010).
8.4 Climate Change Assessment
8.4.1 Projection of Wheat Water Requirements in 2030
To assess the effect of climate change on ETo, climate change scenario RCP6.0
resulted from MIROC5 model in 2030 was used in this analysis. It is available from
the following web site: http://www.ccafs.cgiar.org/marksimgcm#.Ujh1gjGfMY. The MIROC5 model is one of the CMIP5 General Circulation Models
developed by Atmosphere and Ocean Research Institute (The University of Tokyo),
National Institute for Environmental Studies, and Japan Agency for Marine-Earth
Science and Technology. The model has a horizontal resolution of 1.40° × 1.40°.
RCP6.0 climate change scenario is one of the four RCPs scenarios produced by
MIROC5 model to represent a larger set of mitigation scenarios and have different
S. Ouda and A. E.-H. Zohry
models where mean temperatures in the growing season ranged from 15 to 32 °C
with artificial heating. Their results indicated that rise in temperature decreased
grain yield in the majority of wheat growing locations. Average yields for the periods between 1981 and 2010 decreased; ranging between 1% and 28% across 30
sites under increase in temperature by 2 °C. Furthermore, yield losses rose to
between 6% and 55% for a temperature of 4 °C. They also predicted that global
wheat production will fall by 6% for each 1 °C of further temperature increase.
Eyshi Rezaei and Bannayan (2012) studied rain fed wheat yield using the HadCM3
climate change model under the A2 scenario and using DSSAT crop simulation
model. They reported a yield reduction by 50% in the 2040–2069 periods. In another
simulation study in Mexico, Hernandez-Ochoa et al. (2018) projected a general
decline in wheat yields by the 2050s. They also stated that despite the growthstimulating effect of elevated CO 2 concentrations, consistent yield declines were
simulated across most of the main wheat growing regions of Mexico due to the
projected increase in temperature. They added that national wheat production of
Mexico is projected to decline between 6.9% for RCP4.5 and 7.9% for RCP8.5
climate change scenarios.
Using A2 and B2 climate change scenarios developed from HadCM3 model,
Khalil et al. (2009) and Moneir, (2012) found that for wheat planted in clay soil and
surface irrigation, yield losses will occur namely 33–36% and 31–35%, respectively
in both investigations. Whereas, for wheat grown in silty clay soil and under sprinkler system, yield losses were 39% and 34% under A2 and B2 climate change scenarios, respectively (Noreldin et al. 2012). In salt affected soil and under surface
irrigation, wheat yield losses under farmer irrigation practice were high, namely
47% and 44% under A2 and B2 climate change scenarios, respectively (Ouda et al.
2012). Similarly, for farmer irrigation practice in sandy soil and under sprinkler
irrigation, yield losses were 32% and 27% under A2 and B2 climate change scenarios, respectively (Ouda et al. 2010).
8.4 Climate Change Assessment
8.4.1 Projection of Wheat Water Requirements in 2030
To assess the effect of climate change on ETo, climate change scenario RCP6.0
resulted from MIROC5 model in 2030 was used in this analysis. It is available from
the following web site: http://www.ccafs.cgiar.org/marksimgcm#.Ujh1gjGfMY. The MIROC5 model is one of the CMIP5 General Circulation Models
developed by Atmosphere and Ocean Research Institute (The University of Tokyo),
National Institute for Environmental Studies, and Japan Agency for Marine-Earth
Science and Technology. The model has a horizontal resolution of 1.40° × 1.40°.
RCP6.0 climate change scenario is one of the four RCPs scenarios produced by
MIROC5 model to represent a larger set of mitigation scenarios and have different
S. Ouda and A. E.-H. Zohry