Download Assessing Rice Productivity and Adaptation Strategies for the

Assessing Rice Productivity and
Adaptation Strategies for the
Indochinese peninsula under
Climate Change using a Regional
Rice Model
Sanai LI, Jong Ahn Chun, Qingguo Wang
APEC Climate Center
Busan, South Korea
Importance of Agriculture
 agriculture represents the primary
source of employment for 80% of
the Cambodian labor force
 Rice is the most important food
crop in Cambodia, which accounts
for 90% of agricultural land use
and rice production contributes
significantly to national food
supply and the livelihoods of the
rural poor
 Cambodia is highly vulnerable to
climate change, especially to the
effects of flooding and drought
Future challenges

We need sustained growth of crop production
-to enhance rural livelihoods
-to stimulate economic growth
In the Indochina peninsula region, the agriculture sector is
quite vulnerable to climate conditions

-serious environmental challenges
-low technical inputs into agriculture

Food security, remains a
challenge
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The purposes of this study
 Assess the impacts of climate change on
rice production in the Indochinese
peninsula
 test whether adaptive actions: adjustment
of planting dates, adoption of irrigation,
and the use of heat tolerant varieties, can
counter any negative climate impacts
 Assess the uncertainties related to RCMs
 Cambodian potential rice production
capacity in comparison to neighboring
countries
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General Large Area Model for annual
crops (GLAM; Challinor et al, 2004)
 Aims to combine:

the benefits of more empirical approaches (low input data requirements, validity
over large spatial scales) with

the benefits of capturing intra-seasonal variability, and so cope with changing
climates)

The simplified model formulation makes it possible to input less crop parameters
and it can be operated at a relatively larger spatial scale
 Field management -Yield Gap Parameter
 Groundnut, wheat, maize, soybean, rice
general
circulation
model
crop
model
Development of GLAM-rice
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GLAM – Inputs and outputs
INPUTS
Daily weather data:
OUTPUTS
- Rainfall
- Solar radiation
- Min temperature
- Max temperature

Soil water
balance
Soil type

canopy
\

GLAM
Planting date
Leaf
Root
growth

Biomass

Crop Yield
Validation of GLAM-rice at national level of
South Korea from 1996 to 2010
8000
R=0.823, P<0.001
7500
Yield(kg/ha)
7000
6500
6000
5500
Observed yield
simulated yield
5000
4500
4000
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Application of GLAM-rice in seasonal crop forecast
Skill of GLAM-rice at the national level when the model is run using 6 months MME forecast from 6 models
By updating of seasonal forecast with observation, the skill of GLAM-rice
improved as season progresses
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CORDEX-East Asia
GCM
Downscaling
models
HadGEM2-AO
YSU-RSM
HadGEM2-AO
RegCM4
HadGEM2-AO
SNU-MM5
HadGEM2-AO
HadGEM3-RA
ity
y
Institute
Resolution
Periods
Yonsei University
0.44 degrees
1980-2005
2005-2050
0.44 degrees
1979-2005
2006-2050
0.44 degrees
1979-2005
2006-2035
0.44 degrees
1950-2005
2006-2010
Kongju National Univers
Seoul National Universit
National Institute of Met
eorological Research
The daily maximum and minimum temperatures, rainfall, and solar
radiation from four regional climate models (YSU-RSM, RegCM4,
SNU-MM5, and HadGEM3-RA) at a 0.44 × 0.44 degree scale (see
Table 2.1 for details) were re-gridded to a 0.25 × 0.25 degree scale
using the Climate Data Operator (CDO) software
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Validation of GLAM-rice in Cambodia
Scatter plot of the simulated rice yield against the observed
rice yield at a 0.25 × 0.25 degree scale for 2000–2005
GLAM-rice forced with RegCM4 and YSU-RSM had better performance in
reproducing the observed yields than the other two models
GLAM-rice was forced by climate variables from SNU-MM5 and HadGEM3,
the variability in the simulated rice yields was much larger than the
variability in the observations.
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Projected changes in temperature o C
By the 2040s the average seasonal temperature is likely to increase by
about 2 o C
By the 2080s the RCP8.5 scenario shows a great increase in
temperature; the temperature will increase by 4.08-5.35 o C
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Projected changes rainfall (%)
Changes in the average total seasonal rainfall (%) from HadGEM3, YSU-RSM and RegCM4 for the 2020s,
2040s, 2050s and 2080s under the RCP4.5 and RCP8.5 scenarios, relative to the baseline 1990s
Generally, all RCMs show a small increase in projected rainfall for
the 2020s and 2040s relative to the baseline.
HadGEM3 shows a greater increase (20-30%) in seasonal rainfall
for Cambodia and Myanmar for the RCP8.5 scenario
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the climate impacts on rice yields for the Indochinese peninsula
to compare the impacts projected by each RCM
climate change scenarios derived by HadGEM3 lead to the
largest reductions in rice yield
simulated impacts from YSU-RSM and RegCM4 are similar
the projected impact of climate change on rice production
depends on the regional climate model used
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the impacts of climate change on rice yields for the
Indochinese peninsula for 2040s under the RCP4.5
scenarios
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the impacts of climate change on rice yields for the
Indochinese peninsula for 2080s under the RCP4.5
scenarios
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examine how climate variables affect future rice yield
changes in rice yield under future climate scenarios was regressed
against changes in temperature and rainfall using the multiple linear
regression method.
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Changes in rice yields in response to an increase
in temperatures at the country level in the
Indochinese peninsula by 2080s
changes in rice yields are quite sensitive to increases in
temperature, however they are not as sensitive to changes in
rainfall. Each one-degree increase in temperature can cause
about a 10.85% reduction in rice yields.
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the uncertainty in impact assessment
The uncertainty in the projected temperature from climate
models is the main source of uncertainty for the climate change
impact assessment, rather than the uncertainty in projected
rainfall
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Adaptation: shifting the planting date to 20 days
later
Shifting the planting date to 20 days later would have would have a small
beneficial impact on rice yields in Cambodia, Myanmar and Vietnam. The
beneficial impacts for the 2050s and 2080s would be greater
In Thailand, both positive (2050s and 2080s) and negative (2040s and
2040s) impacts on rice yields occur
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Adaptation: irrigation
the predicted rice yields with irrigation would increase by up to 8.242.7%, with the greatest increase in yields in Cambodia and Thailand,
especially for the 2050s and 2080s.
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Impact of extreme temperature on rice yield
Relation between average daily maximum temperature and
spikelet fertility during the flowering period under different
CO2 concentrations(Horie 1993)
.
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Changes in rice
yield(%)
Adaptation: using heat tolerant varieties
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16
14
12
10
8
6
4
2
0
16.9
RCP4.5
2.1
Cambodia
10.9
RCP8.5
3
0
Laos
0.1 0.6
0.5
Myanmar Thailand
0.2
2.4
Vietnam
high temperatures at flowering would have a greater impact
on rice yields in Cambodia and Thailand than in other
countries by 2080s
rice yields would increase by 16.9% and 10.9% in Cambodia
and Thailand, respectively
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challenge to Cambodia’s rice production
 In Cambodia, current rice yields are relatively
low compared to the surrounding countries,
due to low nitrogen, heat and/or water stress,
lower levels of technology, and unfavorable
crop environments
 Global population increases and the negative
impacts of climate change will present a
significant challenge to Cambodia’s rice
production and competition with neighboring
rice producing countries
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How farmers can adapt to the changed climate
farmers can:
 changing the timing of field operations to
make the best use of available water
 adjust sowing dates according to temperature
and rainfall patterns,
 Use high-yielding and stress-resistant
varieties with specific abilities such as
resistance to drought and heat
 improving water use efficiency
Public policy must support farmers
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Policy recommendations
 Raising awareness of climate change among the main
stakeholders and policy-makers,
 Promoting water saving techniques such as watersaving irrigation, collecting rainfall, and saving water
 Building/improving agricultural infrastructure, such as
constructing water-saving irrigation and drainage
systems
 Breeding/Introducing stress-resistant seed varieties
 Developing crop yield monitoring and forecast systems
and improving early warning capabilities before
extreme climate events
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