The Regional Impacts of Climate Change

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2.3.5.4. Transport

The transport sector is based on long-term, immovable infrastructure such as roads, rails, and water. In most parts of the continent, road networks have tended to link industrial centers with major areas of agricultural activity; railways have been designed in the past primarily with a sea-route orientation to facilitate international shipments of primary products. Climate change may lead to industrial relocation, resulting either from sea-level rise in coastal-zone areas or from transitions in agro-ecological zones. This relocation would necessitate additional infrastructural investments. It also may render waterways dysfunctional, thereby necessitating additional road and rail investments to replace them. If sea-level rise occurs, the effect on the many harbors and ports around the continent will be quite devastating economically for many coastal-zone countries. Excessive precipitation, which may occur in some parts of Africa, is likely to have serious negative effects on road networks and air transport. On the other hand, if climate change leads to drier conditions, maintenance costs may be reduced. Typical road networks on the continent consist of gravel roads linking major urban centers, which have paved road systems. Swaziland has a reasonable percentage of paved roads (55% by 1990). The situation is much worse in other countries, as indicated in Table 2-11, which shows the quality of road networks for selected African countries.


Table 2-11: Road networks and density for selected African countries.
Country Vehicles/km Paved Roads % Paved Total (km) Density (km/1,000 km2)
Angola
8,900
12.1
73,400
59
4
Botswana
3,740
20.4
18,330
32
4
Ethiopia
13,300
34.5
38,600
32
1
Kenya
9,800
14.5
67,800
117
5
Lesotho
540
11.2
4,840
161
5
Malawi
2,400
18.3
13,140
111
2
Mauritius
1,795
86
2,090
1,045
65
Mozambique
5,400
15.1
35,700
45
2
Namibia
6,500
8
21
South Africa
29.8
Swaziland
730
21.2
3,450
203
17
Tanzania
3,580
4
82,600
87
1
Uganda (1993)
8,342
21
40,057
166
2.4
Zambia
6,300
16
39,160
52
3
Zimbabwe
13,000
17
78,700
202
5
Average
23
166
10
Source: Zhou and Molcofi, 1997.


Agricultural production activities involve extensive transportation on the farm, to ferry farm products and inputs and to move farm implements. These critical operations are easily disturbed by excessive rains. The effects of such disturbances are likely to be higher in the case of large-scale commercial farms, which are highly mechanized. During recent droughts on the continent, soils on roads became friable as a result of high temperatures and dry weather. Such roads were easily washed away when the rains finally came, resulting in serious soil erosion and high repair costs to farmers. For small-scale communal land farmers, this situation was represented by massive soil erosion along pathways on and off the farm. In many cases, these washed-out pathways became the source of gullies.

Impacts on air transport would be greatest for airports located in coastal areas or near other water bodies, such as rivers or lakes. Indirect effects also would be felt if increased precipitation resulted from climate change, as some models have suggested. In this case, existing air transport support systems-such as meteorological data bases-may be stretched to their limits because they were designed for certain prevailing climates in the continent. Bad weather, in general, would raise the potential for air traffic accidents.


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