Geoscience Reference
In-Depth Information
Tabl e 6. 5
Model predictions of the impact of climate change on
the Nile water budget
Model
a
Temperature rise (K)
Water budget (bcm)
Percent
Base
0
86
100
GFDL
3.15
20
23
UKMO
4.73
76
88
GISS
3.45
112
130
a
Current climate models
1. Increase of temperature increases losses by evaporation and demands for water
for agricultural domestic and industrial applications increase.
2. Change of precipitation patterns will lead to a loss of water in coastal areas if
proper storages are not available to collect runoff from upstream.
3. Increases in airborne dust levels, soil salinity and domestic use decreases water
quality.
4. Sea level rise will increase occurrence of saline intrusion with contamination of
groundwater resources in the coastal zone.
5.1.1
Water Resources
Both water supply and demand are expected to be affected by climate change.
Impacts on the supply side are likely to arise from possible changes of precipitation
patterns over the Ethiopian hills (which accounts for around 85 % of water flow into
the River Nile), and equatorial lakes such as Lake Victoria (15 %). The effects of
predicted climate change on both components are uncertain. The first is dependent
on two factors, namely variation of the general cycle of the wind, and the El-Nino
and ENSO phenomena. The second component is also uncertain due to increased
frequencies of droughts and their intensities over the last two centuries. Rainfall on
the upper White Nile catchment, the upper Blue Nile catchment, and the Middle
Nile basin (which includes the confluence of the two major Nile tributaries), are all
showing a decline in total rainfall and some change in rainfall intensity.
A combination of salt water intrusion due to Sea Level Rise (SLR) and increased
soil salinity due to increased evaporation are expected to reduce the quality of
shallow groundwater supplies in the coastal areas and this will impact both sown
crops and other vegetation as well as those people who rely on groundwater for
their business or for daily living.
5.2
Impact on Agricultural and Food Resources
Intensive, multiple cropping and high occupation rates are normal agricultural
practices in Egypt. More than 6 million ha of crops are cultivated annually on
3 million ha of land, giving an intensity index of 2. (based number of crops per
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