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from the surface in recent years. This is estimated by assum-
ing an average regional precipitation rate of 0.80 m of water
per year since 1998 as calculated using data from the NASA
Goddard Earth Sciences Data and Information Services Cen-
ter. Figure 11 suggests that much of this loss occurred very
recently. Unfortunately, glacier observations are limited
around the world but are even more limited in remote moun-
tains such as the Andes and Himalaya, and thus, they do not
offer a long-term perspective. The biological material (plants
and animals) recently exposed as ice melts and glacier mar-
gins retreat can be radiocarbon dated and thereby provide a
longer-term perspective. As previously mentioned, plants
exposed along the retreating margins of the Quelccaya Ice
Cap conrm that Earth ' is largest tropical ice cap is now
smaller than it has been during at least the last ~5000 years.
The glaciologists at the Institute of Tibetan Plateau Re-
search in Beijing have monitored 612 glaciers across the High
Asia region since 1980. They found that from 1980 to 1990,
90% of these glaciers were retreating, and from 1990 to 2005,
this proportion increased to 95% [Yao et al., 2007]. Meteoro-
logical records from the Tibetan Plateau and the Himalayas
are scarce and of relatively short duration, most beginning in
the mid-1950s to early 1960s; however, those that do exist
show that surface temperatures are rising and rising faster at
higher elevations [Liu and Chen, 2000]. The Tibetan Plateau
has been warming at a rate of 0.16°C per decade, with winter
temperatures rising 0.32°C per decade. However, while ex-
amining 71 meteorological stations in eastern and central
Tibetan Plateau, You et al. [2008] found a general warming
of the plateau from 1961 to 2005 which did not signi
Figure 10. Retreat of the Qori Kalis Glacier, the largest outlet
glacier flowing from the Quelccaya Ice Cap. Included are the retreat
histories for six other Peruvian glaciers located in the Cordillera
Blanca that were monitored by ElectroPeru from the early 1960s to
the early 1990s.
cantly
correlate with elevation. In recent decades, but especially
since 2000, the Tibetan Plateau has experienced a more rapid
warming than surrounding regions [Qin et al., 2009]. Moder-
ate Resolution Imaging Spectroradiometer monthly averaged
land surface data for the whole Plateau show that the warming
rate increases from 3000 to 4800 m, then becomes stable with
a slight decrease near the highest elevations. Using a global
database of 1084 high elevation meteorological stations, Pe-
pin and Lundquist [2008] found that rising temperature trends
through the twentieth century are most rapid near the annual
0°C isotherm due to snow-ice feedback. A 2009 study
[Matsuo and Heki, 2010] shows that from 2003 to 2009, the
average ice loss from the Asian high ice
all shrinking at rates that have markedly increased during the
last few decades. While the percent loss per year on Qori
Kalis and Kilimanjaro accelerated beginning in the 1990s,
Naimona ' nyi has undergone a dramatic decrease in surface
area loss over the last decade [Ye et al., 2006]. The Himalaya
Mountains are home to more than 15,000 glaciers that con-
stitute an important component of the dry season water
supply for India, Nepal, southern China, and Southeast Asia
via the major rivers of the region. Unfortunately, only a few
of the glaciers have been monitored over an extended period,
so the reliable ground observations that are crucial for deter-
mining ice retreat rates do not yet exist. However, a recent
study on an ice core taken in 2006 from the Naimona ' nyi
Glacier indicates that ice is disappearing from the top
[Kehrwald et al., 2008], as shown by the lack of the radio-
active bomb horizons from the 1950s and early 1960s that
appear in all Tibetan and Himalayan ice core records
[Thompson et al., 1989, 1997, 2000, 2006b]. If the top of
the time series from this ice core record is dated to before
1950, then between 30 and 40 m of ice have likely been lost
fields, as measured by
Gravity Recovery and Climate Experiment satellite observa-
tions, had accelerated to twice the rate measured four decades
before, but the recent loss was not consistent over space and
time. Ice retreat in the Himalayas slowed slightly, while loss
in the mountains to the northwest increased markedly over the
last few years.
Thus, taking into consideration the surface temperature
measurements, satellite studies, ground studies on glaciers,
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