and Western Himalaya (Forsythe et al. 2017). The Karakoram
Himalayas appear to have gained glacial mass slightly at the
beginning of twenty-first century, which is contrary to many
other mountain peaks across the globe (Gardelle et al. 2012;
Hewitt 2005; Krishnan et al. 2019a). [More details regarding
WD are provided in Chap. 7.]
More than 30,000 km
2 of the Himalayan region is covered by glaciers which provide about 8.6 million m
3 of water
every year (NASA-LCLUC). Climate change over the past
several decades has influenced the Himalayan mountain
glaciers significantly (Rai and Gurung 2005); however,
detailed information is available only for a few glaciers.
Glaciers in the Chinese Himalayas are reported to have
significantly retreated since the 1950s, with accelerated
retreat after 1990s (Rai and Gurung 2005). Almost all glaciers in the region of the Mount Everest have experienced a
retreat from the late 1990s. Rai and Gurung (2005) reported
that Rongbuk glacier, which is an important source of
freshwater into Tibet, was retreating at the rate of 20 m/a.
The Gangotri glacier in India, which provides a significant
source of meltwater for the Ganges, has retreated about 30 m
every year during the recent decade (Rai and Gurung 2005).
Kulkarni and Pratibha (2018) reported a loss in glacier extent
by 12.6 ± 7.5% for the past 40 years based on a detailed
analysis of 83 glaciers utilising remote sensing and in situ
observations. They further reported maximum loss of glacier
extent in the Eastern Himalaya, near the Tista and Mt.
Everest region, followed by Bhutan and Western Himalayas,
with minimum loss over the Karakoram Himalayas
(Brahmbhatt et al. 2015).
Glacier inventory estimated from satellite images, topographical maps and aerial photographs provides information
about 9040 glaciers covering an area of 18,528 km
2 in the
HKH region (Sangewar and Shukla 2009; Sangewar and
Kulkarni 2010). An illustration of glacier retreat between
1960 and 2000 from Kulkarni and Karyakarte (2014) is
shown in Fig. 11.8. They further showed that the retreat of
the Himalayan glaciers ranges from a few metres to almost
61 m year
−1 , depending on the terrain and meteorological
parameters (Kulkarni and Karyakarte 2014). Mapping of
nearly 20,060 out of *40,000 km
2 of glaciated area, distributed in all major climatic zones of the Himalayas, suggests a loss in glacier area by about 13% during the last four
decades (Kulkarni et al. 2017). Using a high-resolution
cryospheric–hydrological model, Lutz et al. (2014) quantified the run-off of hydrological regimes of major Himalayan
Fig. 11.7 a Spatial map of trend in daily precipitation (APHRODITE)
exceeding the 90th percentile. b Time series of interannual variations of
daily precipitation exceeding 90th percentile over HKH1 from
APHRODITE and TRMM datasets. c Is same as b but from LMDZ
simulation. Dotted areas are trends exceeding 95% confidence level
based on Mann-Kendall test. Reprinted with permission from Krishnan
et al. (2019a)
216
T. P. Sabin et al.
Himalayas appear to have gained glacial mass slightly at the
beginning of twenty-first century, which is contrary to many
other mountain peaks across the globe (Gardelle et al. 2012;
Hewitt 2005; Krishnan et al. 2019a). [More details regarding
WD are provided in Chap. 7.]
More than 30,000 km
2 of the Himalayan region is covered by glaciers which provide about 8.6 million m
3 of water
every year (NASA-LCLUC). Climate change over the past
several decades has influenced the Himalayan mountain
glaciers significantly (Rai and Gurung 2005); however,
detailed information is available only for a few glaciers.
Glaciers in the Chinese Himalayas are reported to have
significantly retreated since the 1950s, with accelerated
retreat after 1990s (Rai and Gurung 2005). Almost all glaciers in the region of the Mount Everest have experienced a
retreat from the late 1990s. Rai and Gurung (2005) reported
that Rongbuk glacier, which is an important source of
freshwater into Tibet, was retreating at the rate of 20 m/a.
The Gangotri glacier in India, which provides a significant
source of meltwater for the Ganges, has retreated about 30 m
every year during the recent decade (Rai and Gurung 2005).
Kulkarni and Pratibha (2018) reported a loss in glacier extent
by 12.6 ± 7.5% for the past 40 years based on a detailed
analysis of 83 glaciers utilising remote sensing and in situ
observations. They further reported maximum loss of glacier
extent in the Eastern Himalaya, near the Tista and Mt.
Everest region, followed by Bhutan and Western Himalayas,
with minimum loss over the Karakoram Himalayas
(Brahmbhatt et al. 2015).
Glacier inventory estimated from satellite images, topographical maps and aerial photographs provides information
about 9040 glaciers covering an area of 18,528 km
2 in the
HKH region (Sangewar and Shukla 2009; Sangewar and
Kulkarni 2010). An illustration of glacier retreat between
1960 and 2000 from Kulkarni and Karyakarte (2014) is
shown in Fig. 11.8. They further showed that the retreat of
the Himalayan glaciers ranges from a few metres to almost
61 m year
−1 , depending on the terrain and meteorological
parameters (Kulkarni and Karyakarte 2014). Mapping of
nearly 20,060 out of *40,000 km
2 of glaciated area, distributed in all major climatic zones of the Himalayas, suggests a loss in glacier area by about 13% during the last four
decades (Kulkarni et al. 2017). Using a high-resolution
cryospheric–hydrological model, Lutz et al. (2014) quantified the run-off of hydrological regimes of major Himalayan
Fig. 11.7 a Spatial map of trend in daily precipitation (APHRODITE)
exceeding the 90th percentile. b Time series of interannual variations of
daily precipitation exceeding 90th percentile over HKH1 from
APHRODITE and TRMM datasets. c Is same as b but from LMDZ
simulation. Dotted areas are trends exceeding 95% confidence level
based on Mann-Kendall test. Reprinted with permission from Krishnan
et al. (2019a)
216
T. P. Sabin et al.