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.
|