New Zealand
in the 20th century, increased temperature became an Apart from a few glaciers on Mt. Ruapehu volcano in
additional driver, although its relative importance is still the North Island, the bulk of New Zealand’s glaciers are
debated
147–149
. Over the last century (1906–2006), these gla- located in the Southern Alps. They reached their maxi-
ciers have lost an estimated 82 per cent of their area – from mum recent extent towards the end of the 18th century,
approximately 21 to 3.8 km². Close to 50 per cent of the with only minor retreat until the end of the 19th cen-
glaciers on the Rwenzori Mountains, Mount Kenya and tury
153
. Total glacier area was 1158 km
2
in 1978, with an
Kilimanjaro have disappeared, while larger glaciers – par- estimated total ice volume of about 53 cubic km
154,155
.
ticularly on Kilimanjaro – have been fragmented
148,150,151
. The overall estimated area and volume changes since
the mid of the 19
th
century are –49 and –61 per cent,
The most pronounced impact of these receding glaciers respectively
156
. Since the mid-1970s, the glaciers overall
is on the scenery. Unlike mountain glaciers in higher lati- have experienced positive mass balances with those hav-
tudes, the shrinking of the East African glaciers will have ing short response times advancing noticeably from the
no significant impact on water resources. The hydrology mid-1980s. This period of advances appeared to be com-
on these mountains is dominated by extensive forest belts ing to an end at the beginning of the new century
157
. A
(hundreds to thousands times larger than the glaciated recent study
85
estimates a net ice volume loss over the
area) with a much higher annual rainfall. If all the glaciers period 1977–2005 of 17 per cent, mainly due to calving
on Kilimanjaro – which has the highest glacier to forest into lakes and associated wasting at glacier tongues.
area ratio – were to melt in just one year, the resulting loss Mass loss due to changes in glacier thickness, excluding
in water resources would be equivalent to only four per that related to lake growth, has contributed only 7 per
cent of the total annual rainfall over the forest belt
152
. cent to the overall ice loss since 1977.
CHAPTER 6B GLACIERS AND ICE CAPS 145