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Supporting Figures
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Systematic differences in crop yield response to climate change resulting from heterogeneity
in cropping intensity
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A. J. Challinor, B. Parkes and J. Ramirez-Villegas
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a. Temperature
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b. Precipitation
Figure S1. Mean temperature (a) and total precipitation (b) for the period covered by the
climate model simulations used in this study, corresponding to 144 calendar days between 1st
June through to 22nd October 2006. Blue boxes marked with letters indicate 3-degree
resolution grid cells where aggregation error was tested, with M for maize and G for
groundnut.
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a. Maize CYG=1
b. Maize CYG=0.5
c. Groundnut CGY=1
d. Maize CYG=0.5
Figure S2. Frequency plot of simulated GLAM yields for maize and groundnut with CYG = 1 (a,c)
and CYG = 0.5 (b,d). The black line represents all grid cells, whereas the blue line shows results
for areas of high cropping intensity, i.e. for maize cultivated area > 0.1 and for groundnut
cultivated area > 0.05.
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a. GLAM 12km All
b. GLAM 12km Intense
c. GLAM 3 deg.
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g. EcoCrop 12km All
h. Ecocrop 12km Intense
i. Ecocrop 3 deg.
Figure S3. GLAM maize yield and EcoCrop suitability response to temperature perturbations
for all grid cells in West Africa. Red thick horizontal line shows the median, boxes extend to 25
% and 75 % of the data and whiskers extend to 5 % and 95 % of the data. Outliers are marked
with red crosses. Three sets of GLAM simulations with CYG=1 are shown: All GLAM 12 km yield
simulations (A), high cropping intensity areas only (b), and 3-degree simulations (c).
Corresponding simulations with CYG = 0.5 are also shown (d,e,fF). Three sets of EcoCrop
simulations are shown: 12 km suitability simulation (g), high cropping intensity areas only (h),
3-degree suitability simulations (i).
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a. CYG=1
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b. CYG=0.5
Figure S4. Temperature sensitivity analysis for groundnut yield with two different values of the
calibration parameter (a: CYG=1; b: CYG=0.5). y-axis shows percentage change in crop yield,
averaged across the grid cells indicated. This figure is the same as main Fig. 3(a) and 3(b),
except for groundnut rather than maize.
Figure S5. Temperature sensitivity analysis for maize yield with YGP = 1. y-axis shows
percentage change in crop yield, averaged across the grid cells indicated.
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Figure S6. Normalised plots of crop yield as a function of area harvested for four combinations
of crops and location.
a. Yield differences (kg/ha)
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b. Yield percentage changes
Figure S7. The difference in yield response between the grid cells with high cropping intensity
and all simulations. Yield responses to changes in both temperature and precipitation are
shown as yield differences without normalisation : (a) all minus Intense, and (b) corresponding
percentage changes. A plus sign indicates that both changes are positive and a minus sign
indicates that the changes are both negative. Yield response at (0,0) is zero by definition. All
yield responses are values averaged across all grid cells.