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by 30 per cent or more by 2050. Several studies
presented in the IPCC’s Fifth Assessment Report
(Niang et al. 2014) find that Kenyan rivers such
as the Mara, the Nyando and the Tana can expect
an increase in water flow during the second half
of this century. Similarly, a study by Rockström
et al (2009), which assesses the impact of climate
change on water availability towards 2050, finds
that water availability will increase in most of the
subregion. Uganda, Burundi and Rwanda, however,
may experience a reduction in water availability, to
between 500 and 1,000 m³ per capita per annum,
but this will largely be due to their rapid population
growth. Ethiopia is also likely to experience a
decrease in water availability, but this will remain
between 1,300 and 1,500 m³ per capita per annum.
A study by Williams and Funk (2011) finds that
the eastern part of the Ethiopian Highlands will
experience reduced precipitation due to climate
change and, as a consequence, the river flow of the
Blue Nile River will decline towards the end of the
century (McCartney and Girmba, 2012). Similar
findings have been reported by Abdo et al. (2009).
Glacial retreat
Melting glaciers have provided the most compelling
evidence of climate change globally. East Africa is the
only subregion of Africa where glaciers are found
and only on the highest summits. They are scattered
across the peaks of Mount Kilimanjaro, Mount Kenya
and the Rwenzori Mountains (Mount Stanley, Speke
and Baker). It is not without reason that the media
and scientists alike are calling this the last chance to
see the glaciers of Africa. Since the 1990s, Africa’s
glaciers have lost 80 per cent of their surface area and,
if the current rate of recession continues, it is very
likely that they will disappear within a few decades
(UNEP, 2014). Six square kilometres of glaciers is all
that is left (Kohler and Masseli, 2012).
The glaciers started to retreat at the beginning of the
1880sduetoreductionsinprecipitationandcloudcover
– this resulted in lower rates of snow accumulation
and higher levels of solar radiation which further
increased the rate of melting (Hastenrath, 2010).
Scientific studies of current glacial retreat do not
agree, however, on the main drivers, which include air
temperature, evaporation, precipitation and humidity
(Campell, 2008; Taylor et al., 2009; Mölg et al., 2009;
Hastenrath, 2010; UNEP, 2012).
According to Taylor et al. (2006), the glaciers on
the Rwenzori Mountains have decreased from
a total of 6.5 km² in 1906 to about 1 km² in 2003.
From 1987 to 2003, the total area of the glaciers
decreased by about 50 per cent. If the current rate
of recession continues, these glaciers will disappear
within the next two decades. The same study argues
that the rapid recession of Rwenzori’s glaciers can be
attributed to the increase in temperature of 0.5 °C per
decade documented since the 1960s in areas close to
the mountain range. An increase in temperature is
also believed to be the reason for the shrinking of
Mount Kenya’s glaciers (Campell, 2008). On Mount
Kilimanjaro, a reduction in precipitation is seen as
the main reason for the shrinking of its glaciers in
recent decades (Mölg et al., 2009). Records indicate
that precipitation has declined in East Africa and that
the higher altitudes, in particular, have become drier.
Data from three weather stations on the southern
slope of Kilimanjaro show that precipitation
decreased by up to 39 per cent between 1911 and
2004 (Hemp, 2005).
Globally, water from melting glaciers provides fresh
water to millions of people. However, in East Africa,
receding glaciers are of little concern for future water
supply. Water from glaciers is relatively insignificant
for total river flows in the region. For example, a study
by Taylor et al. (2009), found that meltwater from the
glaciers onSpeke andElana in theRwenzoriMountains
contributes less than 2 per cent of the discharge of
the Mubuku River. Similar findings are likely for the
glaciers on Mount Kenya and Kilimanjaro. The main
source of fresh water in the Mubuku River is rainwater,
which the area receives in abundance – about 2,340-
2,600 mm a year (Taylor et al., 2009).
Mount Kenya, Kenya