Impact of Climate Change on Arab Countries - (IPCC) - Working ...

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CHAPTER 5
FOOD PRODUCTION
The water situation in the Arab region is threatened
by both environmental and socio-economic
pressures. Many negative impacts <strong>of</strong> climate
change on freshwater systems are observed in
recent studies. These impacts are mainly due to
the observed and projected increases in temperature,
evaporation, sea level and precipitation variability
(IPCC, 2007a). Decreases in precipitation
are predicted by more than 90% <strong>of</strong> climate
model simulations by the end <strong>of</strong> the 21st century
for the North Africa and Middle East region
(IPCC, 2007b).
<strong>Change</strong>s in annual mean run<strong>of</strong>f are indicative <strong>of</strong>
the mean water availability for vegetation.
Projected changes between now and 2100 show
some consistent run<strong>of</strong>f patterns: increases in high
latitudes and the wet tropics, and decreases in
mid-latitudes and some parts <strong>of</strong> the dry tropics.
Declines in water availability are therefore projected
to affect some <strong>of</strong> the areas currently suitable
for rain-fed crops (e.g., in the Mediterranean
basin and sub-tropical regions) (Christensen et
al., 2007).
<strong>Climate</strong> change will increase consumptive water
use in key sectors in the future, especially in
countries that have limited water resources, high
population growth and high development rates
(Medany, 2007). Magano et al. (2007) point out
that irrigation demands will increase and the irrigation
period <strong>of</strong> supplementary irrigation will
become longer under projected climate changes.
For example, the total annual reference irrigation
demands <strong>of</strong> Egypt are projected to increase by 6
to 16% by the 2100s, due to the increase in reference
evapotranspiration values, which will lead
to a general increase in the crop-water demands.
Figure 1 illustrates the change in crop-water
requirements <strong>of</strong> major field and vegetable crops
due to the change in temperature and CO 2 levels
based on the IPCC SRES A1 and B1 scenarios
for the 2025s, 2050s and 2100s (Medany, 2008).
Smallholder agriculture is used here to describe
rural producers, who farm using mainly family
labour and for whom the farm provides the
principal source <strong>of</strong> income (Cornish, 1998).
Pastoralists and people dependent on artisanal
fisheries and household aquaculture enterprises
(Allison and Ellis, 2001) are also included in this
category. Smallholders in most <strong>of</strong> the Arab
countries are poor and suffer in varying degrees
from problems associated both with subsistence
production (isolated and marginal location,
small farm size, informal land tenure and low
levels <strong>of</strong> technology), and with uneven and
unpredictable exposure to world markets, which
FIGURE 1
CHANGE BETWEEN CURRENT AND FUTURE VALUES (FOR YEARS 2025S, 2050S AND 2100S) AT NATION-
AL LEVEL SEASONAL CROP-WATER REQUIREMENTS OF SOME FIELD AND VEGETABLE MAJOR CROPS
16
Crop-water requirement change (%)
14
12
10
8
6
4
2
0
2025 2050 2100 2025 2050 2100
Wheat [W] Tom ato [N] Potato [S] Maize [N] Potato [W]
M aize [S]
A1
Tom ato [W ] Broad Bean [W ] Tom ato [S] Potato [N]
Source: Medany, 2008 W: Winter season S: Summer season N: Nili season
B1