usaid/nambia environmental threats and opportunities assessment

The findings by Turpie et al 2010 can be summarized as follows :-
It is predicted with a high degree of certainty that Namibia will experience increasing
temperatures which will be higher inland than at the coast (an increase of between 2 - 6°C
depending on the locality)
It is estimated that for every degree of temperature rise in Namibia, potential evaporation will
increases by 5%.
It is predicted with a fair degree of certainty that Namibia can expect a 10% decrease in rainfall
in the northern and southern regions, and a 20% decrease in the central part of the country by
2050. This situation will worsen with possible rainfall reductions of 20% and 30% respectively by
2080. Despite these predictions there is a possibility that eastern Caprivi will receive more rain,
as this (currently) sub-humid area lies on the edge of the ITCZ which, under many predictions,
will become wetter in future decades. In all likelihood this will translate into increased rainfall
variability in this region.
The fire-affected areas of Namibia presently lie above the 250 mm rainfall isohyet and currently
affect Caprivi far more than Kunene. With climate change, under the decreasing/more variable
rainfall scenario, a commensurate eastward shift in fire frequency is likely which means that
Kunene will become less vulnerable to seasonal fire hazards.
Future precipitation in the Angolan highlands and Zambia is predicted to increase. This will
influence streamflows in Namibia’s northern rivers, which are likely to experience a 10 – 15%
increase in water volume – with floods becoming more frequent and of greater magnitude.
The cumulative impacts of higher temperature, lower rainfall, lower humidity, higher evaporation
rates and lower plant cover will cause dramatically reduced soil moisture and primary production
(PP) and a corresponding decline in carrying capacity. Increasing aridification will result in a shift
in the hyper-arid desert and arid shrublands eastwards.
The reduced primary production of rangelands could be offset to some degree by the CO 2
fertilisation effect.
A decline in numbers of large trees in westward flowing ephemeral rivers (linear oases) will occur
due to lower water tables, increasing elephant damage and increasing upstream abstraction.
A loss of unique (endemic) plant assemblages that occur on the western escarpment is predicted.
There is the likelihood of improved availability of arid-adapted veldkos and important INP species
(e.g. Commiphora; Harpagophytum & Hoodia). Commiphora ,for example, produces more resins (the
valuable INP ingredient) when under stress.
With respect to water availability the following responses are expected:-
Periodically higher flows in the Kunene River and other north eastern perennial rivers – more
intense and frequent flooding events.
Lower flows in the Orange river.
Declining surface water (small springs, seeps etc) which will affect wildlife presence in the more
arid parts of the country.
98 USAID/NAMIBIA ENVIRONMENTAL THREATS AND OPPORTUNITIES ASSESSMENT