Botswana’s key environmental issues are influenced by, or relate to, (1) climate, (2) water
resources, (3) the management of land, (4) forests, vegetation and ecosystems, (5) conditions in
human settlements, (6) mineral resources and geology and (6) archaeological and cultural
resources.
Climate.
Botswana is largely arid or semi-arid because of geographic location. Rainfall, which is unreliable
and unevenly distributed, varies widely from about 250 mm in the south-west to about 650 mm in
the north-east of the country. Variations in temperatures are similarly high. Average daily
maximum temperature ranges from 22 °C in July to 33 °C in January, with an average daily
minimum of 5 °C in July and 19 °C in January. Extreme temperatures can reach 43 °C in January,
resulting in very high evaporation rates.
The country is susceptible to seasonal variations in climate which are influenced by the La Nina
and El Nino events. The latter contributes to drought conditions which, in turn, reduce water
supply as well as agricultural production. Drought, therefore, affects the livelihoods of the large
population which is dependent on agriculture and the rural communities that depend on individual
water sources that cannot withstand prolonged drought. The severity and extent of drought is
difficult to predict due to the absence of a fully established monitoring system and scarcity of
long-term data sets.
Botswana is highly vulnerable to climate change, even though the country is estimated to be a net
sink of greenhouse gases. Although a wet scenario is possible, most climate change models for
the region indicate generally drier conditions in future, which would reduce agricultural production,
and result in more severe drought and desertification.
Water
Water demand in all the sectors is expected to increase from 120 million cubic metres in 1990 to
335 Million cubic metres in 2020 due to population growth, improvements in living conditions, and
economic development. The major water users are human settlements, livestock, mining and
energy and irrigation.
The provision of reliable water supply is costly because Botswana has few surface water sources.
This is due to low rainfall, high seepage because of generally sandy soils, and high evaporation
rates. All rivers, apart from the Okavango and Chobe, are ephemeral. Consequently, dams have
been constructed to improve water supply mainly for urban areas. The uneven spatial distribution
of surface water has required costly transfers of the resource, within the country and from
outside.
Ground water is important, especially for rural communities, because of the limited supply of
surface water. The high reliance on ground water (estimated to be 80% in 2005) poses several
challenges. These include the protection of aquifers from pollution, the high cost of provision due
to the depth at which it is available, high levels of salinity in some places and the absence of
precise knowledge on the rate at which it is being recharged, which makes the determination of
future availability difficult.