Abstract:
This study investigates the future climatic impacts of different percentages of trees/shrubs,
C4 and C3 plant functional types (PFTs) over theWest Africa region. The ratio of co-existence among the
different PFTs was done as a representation of agri-silviculture practices over the region. Nine sensitivity
experiments of different percentages of trees/shrubs, and C4 and C3 PFTswere carried outwith a regional
climate model (RegCM4) driven by Global ClimateModel (HADGEM2-ES) outputs. These experiments
were carried out along the Guinea Savana zone of West Africa using both prescribed and dynamic
vegetation options of the model. The model simulated the seasonal evolution of precipitation and
temperature fields quite well, with correlations greater than 0.8, but exhibited cold and wet biases of
about 1–2 C and 1–4 mm/day, respectively. Widespread warming (1–3 C) and drying (1–2 mm/day)
is projected in the near future across most parts ofWest Africa all year round. TheWest African future
climate change associated with the different percentages of trees/shrubs, and C4 and C3 PFTs varied
with the vegetation state (prescribed or dynamic) and model domain sizes. The prescribed vegetation
experiments induced cooling of about 0.5–2 C in most areas along the designated agri-silviculture zone,
except Liberia and Sierra Leone. Similarly, enhanced precipitation occurred over most parts of Ghana
and coastal parts of Nigeria (0.5–3 mm/day). On the other hand, the dynamic vegetation option did
not exhibit pronounced changes in temperature and precipitation, except with a larger domain size.
This study suggests the implementation of agri-silviculture as a mitigation and adaptation land-use
practice acrossWest Africa if drought-tolerant crops and the deciduous trees are adopted.
