46
cereal crops, including maize, by 20–30% by 2050 (Liu et al. 2008; Schlenker and
Lobell 2010).
In agreement with past studies, EcoCrop analyses predict that climate change
will result in minor but widespread decreases in the crop suitability index score for
maize in the planalto region by 2050, particularly at the onset of the rainy season in
October. In Huíla province, the absolute spatial extent of areas which are suitable
for maize production are predicted to decrease considerably as a result of climate
change, to the extent that the entire province is likely to become poorly suited to the
crop by 2050. Of the remaining five provinces, the maize-suitable production areas
are predicted to remain unchanged in absolute spatial extent but will undergo
decreases in crop suitability index score.
In addition to the effects of increasing temperature, a major challenge that will
affect maize farmers in Angola is the projected delay in onset of the rainy season as
a result of climate change. The trend towards reduced suitability for maize production is likely to be attributable to the predicted decreases in rainfall over the growing
season; EcoCrop’s parameters specify a minimum seasonal rainfall of 400 mm and
optimum rainfall of at least 600 mm. Analysis of GCMs suggest that onset of rainfall is likely to shift from October/November to December/January by 2050. For
households practicing rain-fed maize cultivation, the delayed rains will increase the
duration of the “lean” season, when households are reliant on the previous season’s
harvest. Households therefore will need to adopt new strategies to ensure that food
reserves (and adequate seed for planting) can last through this longer lean season. It
is unclear whether a long-term shift in the onset of Angola’s rainy season will result
in a delay to the planting season, or whether changing rainfall patterns will shorten
the effective growing season. It is recommended that Angola urgently promote the
development and adoption of locally adapted, improved maize cultivars that are
more tolerant to heat and drought stress and that can grow to maturity within the
confines of a shortened or variable growing season, as well as the promotion of
comparatively drought-resilient cereals such as millet and sorghum.
4.4 Implications for Development
The approach and results presented in this chapter demonstrate the use of downscaled climate projections and crop suitability models as a useful but broad-level
means of assessing the possible effects of climate change on the temporal and spatial distribution of crop suitability. This is particularly important in countries such as
Angola where agronomic data and climate measurements are not readily available.
In this case study of six provinces in the planalto region of Angola, the diverse
impacts of climate change on the crops analysed cannot be easily generalised across
the entire study area and indicate the need for detailed local-level studies and strategies for intervention.
R. Hunter and O. Crespo
cereal crops, including maize, by 20–30% by 2050 (Liu et al. 2008; Schlenker and
Lobell 2010).
In agreement with past studies, EcoCrop analyses predict that climate change
will result in minor but widespread decreases in the crop suitability index score for
maize in the planalto region by 2050, particularly at the onset of the rainy season in
October. In Huíla province, the absolute spatial extent of areas which are suitable
for maize production are predicted to decrease considerably as a result of climate
change, to the extent that the entire province is likely to become poorly suited to the
crop by 2050. Of the remaining five provinces, the maize-suitable production areas
are predicted to remain unchanged in absolute spatial extent but will undergo
decreases in crop suitability index score.
In addition to the effects of increasing temperature, a major challenge that will
affect maize farmers in Angola is the projected delay in onset of the rainy season as
a result of climate change. The trend towards reduced suitability for maize production is likely to be attributable to the predicted decreases in rainfall over the growing
season; EcoCrop’s parameters specify a minimum seasonal rainfall of 400 mm and
optimum rainfall of at least 600 mm. Analysis of GCMs suggest that onset of rainfall is likely to shift from October/November to December/January by 2050. For
households practicing rain-fed maize cultivation, the delayed rains will increase the
duration of the “lean” season, when households are reliant on the previous season’s
harvest. Households therefore will need to adopt new strategies to ensure that food
reserves (and adequate seed for planting) can last through this longer lean season. It
is unclear whether a long-term shift in the onset of Angola’s rainy season will result
in a delay to the planting season, or whether changing rainfall patterns will shorten
the effective growing season. It is recommended that Angola urgently promote the
development and adoption of locally adapted, improved maize cultivars that are
more tolerant to heat and drought stress and that can grow to maturity within the
confines of a shortened or variable growing season, as well as the promotion of
comparatively drought-resilient cereals such as millet and sorghum.
4.4 Implications for Development
The approach and results presented in this chapter demonstrate the use of downscaled climate projections and crop suitability models as a useful but broad-level
means of assessing the possible effects of climate change on the temporal and spatial distribution of crop suitability. This is particularly important in countries such as
Angola where agronomic data and climate measurements are not readily available.
In this case study of six provinces in the planalto region of Angola, the diverse
impacts of climate change on the crops analysed cannot be easily generalised across
the entire study area and indicate the need for detailed local-level studies and strategies for intervention.
R. Hunter and O. Crespo