41
about 1 km
2
(a resolution grid of 30 arc-sec) (Hijmans et al. 2005). Interpolations of
observed data for the period 1960–1990 are henceforth referred to as the “historical
baseline” period.
The future effects of climate change in the study area were computed based on
analysis of 29 general circulation models (GCMs) downloaded from the AgMERRA
dataset (Ruane et al. 2015). Future climate changes in 2050 for monthly mean temperature (Tmean), monthly minimum temperature (Tmin), and monthly mean precipitation (Precip) were computed assuming the scenario of RCP 8.5 (high emission
pathway).
4.2.2 Analysis of Crop Suitability
The influence of future climate change predictions on crop suitability was assessed
using the Ecocrop suitability model developed by the Food and Agriculture
Organisation (Ecocrop 2010), based on the methodologies described in RamirezVillegas et al. (2013). The Ecocrop model calculates the relative suitability of a crop
in response to a range of climate variables such as temperature, rainfall; and growing period, thereby generating a suitability index score ranging from 0 (totally
unsuitable) to 1 (optimal/excellent suitability) as an output. It should be noted that
this study did not undertake any additional ground-truthing or calibration of the
range of climate parameters preferred for either crop, and therefore the default
EcoCrop parameters were assumed. Suitability index scores were calculated for the
range of climate variables reported for the historical baseline period (WorldClim
data) and future (GCM predictions for 2050).
4.3 Results and Discussion
4.3.1 Projected Climate Changes
By 2050 a clear trend of warming is projected across the entire study region throughout all months of the year, with predictions of increases of Tmin and Tmean of
approximately 1–2.5 °C. The mean and minimum monthly temperature (Tmean and
Tmin) is predicted to increase by 1.5–2 °C in the eastern and southern interior of the
country (including large areas of Bié, Huambo, Huíla and Malanje provinces), and
increases of about 1 °C predicted for the coastal, central and northern regions of the
country. Figure 4.2 depicts the spatial distribution of Tmin and Tmean (left and
centre, respectively), with anomalies between the two time periods indicated by red
shading (bottom row).
With respect to predicted effects of climate change on rainfall, it is projected that
the onset of the rainy season (typically September–October) in 2050 will be charac4 Large Scale Crop Suitability Assessment Under Future Climate Using the Ecocrop…
about 1 km
2
(a resolution grid of 30 arc-sec) (Hijmans et al. 2005). Interpolations of
observed data for the period 1960–1990 are henceforth referred to as the “historical
baseline” period.
The future effects of climate change in the study area were computed based on
analysis of 29 general circulation models (GCMs) downloaded from the AgMERRA
dataset (Ruane et al. 2015). Future climate changes in 2050 for monthly mean temperature (Tmean), monthly minimum temperature (Tmin), and monthly mean precipitation (Precip) were computed assuming the scenario of RCP 8.5 (high emission
pathway).
4.2.2 Analysis of Crop Suitability
The influence of future climate change predictions on crop suitability was assessed
using the Ecocrop suitability model developed by the Food and Agriculture
Organisation (Ecocrop 2010), based on the methodologies described in RamirezVillegas et al. (2013). The Ecocrop model calculates the relative suitability of a crop
in response to a range of climate variables such as temperature, rainfall; and growing period, thereby generating a suitability index score ranging from 0 (totally
unsuitable) to 1 (optimal/excellent suitability) as an output. It should be noted that
this study did not undertake any additional ground-truthing or calibration of the
range of climate parameters preferred for either crop, and therefore the default
EcoCrop parameters were assumed. Suitability index scores were calculated for the
range of climate variables reported for the historical baseline period (WorldClim
data) and future (GCM predictions for 2050).
4.3 Results and Discussion
4.3.1 Projected Climate Changes
By 2050 a clear trend of warming is projected across the entire study region throughout all months of the year, with predictions of increases of Tmin and Tmean of
approximately 1–2.5 °C. The mean and minimum monthly temperature (Tmean and
Tmin) is predicted to increase by 1.5–2 °C in the eastern and southern interior of the
country (including large areas of Bié, Huambo, Huíla and Malanje provinces), and
increases of about 1 °C predicted for the coastal, central and northern regions of the
country. Figure 4.2 depicts the spatial distribution of Tmin and Tmean (left and
centre, respectively), with anomalies between the two time periods indicated by red
shading (bottom row).
With respect to predicted effects of climate change on rainfall, it is projected that
the onset of the rainy season (typically September–October) in 2050 will be charac4 Large Scale Crop Suitability Assessment Under Future Climate Using the Ecocrop…