usaid/nambia environmental threats and opportunities assessment

MAJOR THREAT 5. BUSH ENCROACHMENT
It is estimated that 26 million hectares of rangeland is encroached with bush, at current prices leading to
economic losses estimated at N$1.2 billion per year. Bush encroachment is therefore one of the most
serious and costly forms of habitat degradation in Namibia.
The Government recognizes that bush encroachment is causing a severe drain on rangeland productivity,
but has not yet implemented measures to actively combat it. This is left up to individual farmers, who
must carry the high cost of bush thinning. For many (especially on relatively small farms), it is
unaffordable. Activities such as harvesting wood for charcoal production, firewood and fencing stakes,
are helping farmers to derive financial benefits from encroacher wood so that the cost of clearing is
offset.
MAJOR THREAT 6. CLIMATE CHANGE
The expected increasing temperatures, lower and more variable precipitation, higher rates of evaporation,
and reduced soil moisture suggest that vegetation in Namibia will show a noticeable shift in spatial
dominance from Grassy Savanna to Desert and Arid Shrubland by 2080. The following important
implications for agriculture and rangelands are expected:
Arid vegetation types will increase in cover by about 20% by 2050, and up to 43% by 2080 in the
absence of a CO 2 fertilization effect. 22 With CO 2 fertilization modelled, the expansion by 2080 is
reduced from 43% to just under 30% (Midgely et al 2005).
There will be a reduction in ground cover and reduced Net Primary Productivity throughout
much of the country by 2050 (exacerbated by 2080).
Rising atmospheric CO 2 could increase primary productivity in certain plants. This suggests that
bush encroachment in some regions may intensify.
A steady decline in rain-fed crop production will occur until this activity becomes no longer
viable except in eastern Kavango and Caprivi.
Much higher irrigation water demands, increased use of fertilizers and pesticides – the latter in
response to increased pestilence and disease.
Fewer but more intense rainfall episodes will result in increased rates of erosion. They will also
have negative impacts on seed germination.
Namibia’s long-term carrying capacity for large livestock is already exceeded in many places and
under climate change predictions a mean loss of 28% of livestock revenue below 2009 estimates
can be expected by 2050 (Brown 2009).
The productive area for large stock in Namibia will shrink towards the east and north and it is
estimated that cattle numbers could decline to about 76% of present numbers by 2050 and 51%
of present numbers by 2080 (ibid). Cattle will probably be replaced by small stock, which is better
suited to arid conditions. The productive area for small stock will retreat from the west and
expand towards the north and east. Despite an overall increase in productive range the numbers
22 While there is considerable uncertainty pertaining to the CO2 fertilization effect on plants, higher CO2 could enhance the
reduced dominance of Grassy Savanna by 2080 (by exacerbating the increase in C3-dominated vegetation types, Woody
Savanna, Mixed Grassland, and C3 Grassland/Shrubland) (Midgely, 2005)
68 USAID/NAMIBIA ENVIRONMENTAL THREATS AND OPPORTUNITIES ASSESSMENT