The Impacts of Climate Change on Regional Water Resources and Agriculture in Africa

This paper summarizes the methods and
findings of the hydrological assessment component of the
project studying likely impacts of climate change on water
resources and agriculture in Africa. The first phase of the
study used a version of a conceptual rainfall-runoff model
called WatBal (Water Balance) applied to gridded data to
simulate changes in soil moisture and runoff across the
whole continent of Africa rather than to any particular
catchment or water resource system. The model inputs were
the climate variables of the 1961-90 climatology and
physiological parameters (such as soil properties and land
use) derived from global datasets for each of the 0.5 degree
latitude/longitude cells across the continent. The primary
model output comprised a time series (monthly time step) of
simulated runoff for all the grid cells for each of the
districts in the countries of interest. The second phase of
the study extended the hydrology analyses to update the
above hydroclimatic series to the year 2000 using updated
input data. To ascertain the possible impacts of climate
change within the districts being investigated this study
used synthetic or GCM-based climate change scenarios as
input to the WatBal model. The WatBal model was used to
determine the impact of these different scenarios on runoff
and actual evaporation and hence flow in the districts under
study. The generated hydroclimatic series and scenario
analyses were used as inputs into various Ricardian
regressions in other analyses measuring likely impacts of
climate change on the agricultural economies of Africa.