Policy Brief: State of Himalayan glaciers and future projections

Abstract

Highlights: • Snow and glacier melt is one of the major source of water in Himalaya and it influences the water security in north-India. Himalayan states (Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and Arunachal Pradesh) and lowland states (Uttar Pradesh, Punjab, Haryana, Bihar, Assam and West Bengal) depend on this source of water. Together, these states constitute approximately 44% of India's population (Census, 2011). • Glacial stored water in Indian Himalaya is 3,651 Giga-ton (Gt) and losing mass at the rate of 6.6 ± 1 Gt per annum. This has led to 13% loss in total area from 1960-2000. [1] • Loss in glacier mass has implications for: (i) Water and food security (ii) Glacial Lake Outburst Floods (GLOF) and (iii) Hydropower generation. • For last 3 decades, mean temperature in Himalaya is higher than global mean. Further, decrease in snowfall and increase in rainfall is observed. [2] • Model projections suggest Himalayan region will experience temperature rise of approximately 2.36 0 C in low emission scenario and approximately 5.51 0 C in high emission scenario by the end of 21 st century. [3] • The present pattern of stream runoff and availability of water resources could be largely maintained if global temperature rise is restricted below 2 0 C. Temperature rise of 5.51 0 C by the end of 21 st century will result in additional loss of 27% of the glacier area. [3] • Paris Agreement aims to limit global warming below 2 0 C. A global concerted effort is required to mitigate climate change. Even in a scenario where Paris goals are attained, some degree of climate change is inevitable. So, India should also focus on adaptation activities at the state and district level to minimize future damages. • We can save the Himalayan glaciers if all the major countries of the world were to follow India's example by at least implementing their respective Paris Agreement goals.

Full text

Divecha Centre for Climate Change
Indian Institute of Science, Bengaluru Policy Brief
March 2018
State of Himalayan glaciers and future projections
Ashutosh Kulkarni, Pratibha S, Rajiv Chaturvedi, Anil Kulkarni, SK Satheesh
Highlights:
• Snow and glacier melt is one of the major source of water in Himalaya and it influences the water security in
north-India. Himalayan states (Jammu & Kashmir, Himachal Pradesh, Uttarakhand, Sikkim and Arunachal
Pradesh) and lowland states (Uttar Pradesh, Punjab, Haryana, Bihar, Assam and West Bengal) depend on
this source of water. Together, these states constitute approximately 44% of India’s population (Census,
2011).
• Glacial stored water in Indian Himalaya is 3,651 Giga-ton (Gt) and losing mass at the rate of 6.6 ± 1 Gt per
annum. This has led to 13% loss in total area from 1960-2000. [1]
• Loss in glacier mass has implications for: (i) Water and food security (ii) Glacial Lake Outburst Floods (GLOF)
and (iii) Hydropower generation.
• For last 3 decades, mean temperature in Himalaya is higher than global mean. Further, decrease in snowfall
and increase in rainfall is observed. [2]
• Model projections suggest Himalayan region will experience temperature rise of approximately 2.360C in
low emission scenario and approximately 5.510C in high emission scenario by the end of 21st century. [3]
• The present pattern of stream runoff and availability of water resources could be largely maintained if global
temperature rise is restricted below 20C. Temperature rise of 5.51 0C by the end of 21st century will result in
additional loss of 27% of the glacier area. [3]
• Paris Agreement aims to limit global warming below 20C. A global concerted effort is required to mitigate
climate change. Even in a scenario where Paris goals are attained, some degree of climate change is
inevitable. So, India should also focus on adaptation activities at the state and district level to minimize
future damages.
• We can save the Himalayan glaciers if all the major countries of the world were to follow India’s example by
at least implementing their respective Paris Agreement goals.

Water Security for North India
Indus, Ganga and Brahmaputra, 3 major river basins, form the
lifeline for water security of North Indian states.
The snow and glacier meltwater contribution for upper Indus
is up to 72% and 10-30% for upper Ganga. This difference
is likely due to high monsoon rainfall in Ganga basin as
compared to Indus.
To highlight the importance of snow and glacier melt water,
for example, in Bhakra dam, the contribution of glacier and
snow meltwater is approximately 59% [5]. For the state of
Punjab, Haryana, Delhi and Rajasthan, this has implications
on: water security, food security and hydropower generation.
Divecha Centre for Climate Change
Figure 2: Location of Glaciers where retreat was measured from 1960-2000. The basin wise retreat is represented in yellow star. Glacial mass
loss is 6.6 ± 1 Giga-ton per annum and overall loss in glacier area is 13%. [1], [6]
2 Policy Brief - March 2018
Figure 1: Geographic location of three main rivers (Indus, Ganga & Brahmaputra) and the various regions in Himalaya.
Observed Changes in Himalayan Glaciers
Areal extent of entire Himalayan range (including Karakoram)
is 40,000 Km2. Out of this, Indian Himalaya constitute 23,314
Km2 and stores 3,651 Giga-ton of glacier water. [1]
Himalayan glaciers are losing mass at a rate of 6.6 ± 1 Giga-
ton per annum. 81 glaciers spread over different climate zones
were used to assess this rate of retreat. [1]
Himalaya has lost 13% of glacier area over the period of 40
years from 1960-2000. This loss was estimated using satellite
images. [1]

Divecha Centre for Climate Change
3 Policy Brief - March 2018
Table-1: Percentage glacier area loss and average rate of retreat for glaciers in 3 basins [6]
BASIN Glacier Area Loss (% per decade) Avg. retreat rate (meters per decade)
Indus 3.72 (+ 1.93) 178 (+ 138)
Ganga 3.03 (+ 2.25) 148 (+ 97)
Brahmaputra 3.22 (+ 1.83) 135 (+ 110)
Case Study: Samudra Tapu Glacier
Samudra Tapu is a well-studied glacier in Chandra basin, H.P.
It is one of the largest glacier in the basin and its areal extent
has reduced from 73 Km2 (1960) to 65 Km2 (2000) i.e. loss of
11% in area. [7] The glacier retreated by 742 m from 1960 to
2000. This continuous retreat has aided in the expansion of
lake at its terminus. In 2015, the lake covered an area of 138
hectares and models show that upon further deglaciation, the
existing lake could expand by an area of 14 ± 2 hectares. [8]
Figure 3: Field photographs of Samudra Tapu glacier terminus showing glacier retreat and expansion of glacier lake.
Figure 4: Comparison of increase in global mean temperature
with mean temperature rise in Greater Himalaya zone of Western
Himalaya. For global temperature, the base period is 1901-2000 and
for Himalayan region, the base period is 1990-2015.
-1
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1
1990 1995 2000 2005 2010 2015
Mean Temperature anomaly
Temperature anomalies
Western Himalaya
Global
Climate change in Himalaya
Temperature and precipitation change (rainfall & snowfall)
are key indicators of climate change.
Global temperature, on average, has increased by 0.850C from
1880-2012 [9]. However, the rise in temperature observed in
Himalaya from 1990 is much higher than the global average.
[2]
For the entire region of Western Himalaya and Karakoram,
shown in figure-1, the total observed increase in mean
temperature from 1991-2015 was 0.650C. [2]
Snowfall for the period of 1991-2015 has decreased with
concurrent increase in rainfall. [2]
This has led to the loss in glacier area by 13% from 1962 to
2000. [1]
Recent survey of communities in high altitude region of
western Himalaya show increase in temperature. Since these
communities mainly depend on glacier and snow melt for
their water needs, they are likely to experience changes in
water availibility in future.

4 Policy Brief - March 2018
Divecha Centre for Climate Change
References
[1] A. V. Kulkarni and Y. Karyakarte, “Observed changes in
Himalayan glaciers,” Curr. Sci., vol. 106, no. 2, pp. 237–244,
2014
[2] H. S. Negi, N. Kanda, M. S. Shekhar, and A. Ganju,
“Recent wintertime climatic variability over the Recent
wintertime climatic variability over the North West Himalayan
cryosphere,” Curr. Sci., vol. 114, no. February, 2018
[3] R. K. Chaturvedi, A. Kulkarni, Y. Karyakarte, J. Joshi, and
G. Bala, “Glacial mass balance changes in the Karakoram and
Himalaya based on CMIP5 multi-model climate projections,”
Clim. Change, vol. 123, no. 2, pp. 315–328, 2014
[4] “The State and Fate of Himalayan Glaciers,” Science, vol.
336, pp. 310–314, 2012
[5] P. Singh and S. K. Jain, “Snow and glacier melt in the
Satluj River at Bhakra Dam in the western Himalayan region,”
Hydrol. Sci. J., vol. 47, no. 1, pp. 93–106, 2002
[6] A. Kulkarni and Pratibha. S, “Assessment of Glacier
Fluctuations in the Himalaya.,” in Science and Geopolitics of
The White World. Springer, Cham, 2018
[7] A. V. Kulkarni, S. Dhar, B. P. Rathore, K. Babu Govindha Raj,
and R. Kalia, “Recession of Samudra Tapu glacier, Chandra
river basin, Himachal Pradesh,” J. Indian Soc. Remote Sens.,
vol. 34, no. 1, pp. 39–46, 2006
[8] U. S. Maanya, A. V. Kulkarni, A. Tiwari, E. D. Bhar, and J.
Srinivasan, “Identification of potential glacial lake sites and
mapping maximum extent of existing glacier lakes in Drang
Drung and Samudra Tapu glaciers, Indian Himalaya,” Curr.
Sci., vol. 111, no. 3, pp. 553–560, 2016
[9] IPCC, 2014: Climate Change 2014: Synthesis Report.
Contribution of Working Groups I, II and III to the Fifth
Assessment Report of the Intergovernmental Panel on Climate
Change [Core Writing Team, R.K. Pachauri and L.A. Meyer
(eds.)]. IPCC, Geneva, Switzerland, 151 pp
Acknowledgements
We would like to thank Divecha Center for Climate Change for
providing funds to carry out this work. This work was carried
out by a large number of researchers at glacier lab and we
would like to acknowledge their contribution. We are also
thankful to Prof. J. Srinivasan for his valuable suggestions.
Predicting future Changes in Himalayan
Glaciers
Future projections of climate change are based on how
atmospheric concentration of greenhouse gases (GHG) vary.
If low GHG emission scenario is followed, the increase in
mean temperature in Himalaya by the end of 21st century will
be limited to 2.360C. On the other hand, if high-end emissions
scenario is followed, the mean temperature in the Himalaya
is expected to increase to 5.510C by the end of 21st century,
relative to the pre-industrial period (1880s). [3]
In the Himalayan region, the rise in the temperature and
concurrent decrease in snowfall will reduce the snow cover
area and volume in coming decades. Subsequently, this will
have influence on the water availability for the communities
in the high-altitude regions.
Figure 6: Observed and predicted glacier mass loss. Himalaya
is currently losing a mass of 6.6 ±1 Giga-ton every year. If the
temperature in Himalaya rises by 2.360C by the end of 21st century,
they would be losing 12 ± 2 Giga-ton every year that time onward. If
the temperature in Himalaya rises by 5.510C by the end of 21st century,
they would be losing 35 ± 2 Giga-ton every year that time onward.
12
35
0
5
10
15
20
25
30
35
40
Temperature rise
(2.36 deg C)
Temperature rise
(5.51 deg C)
Giga-ton per annum
Glacier Mass Loss
(end of 21st century)
Figure 5: Inter-annual variation in wintertime rainfall and snowfall for
25 years. Total precipitation was observed to increase; with decrease
in snowfall and concurrent significant increase in rainfall. [2]
0
100
200
300
400
500
600
700
800
900
1000
1991
1993
1995
1997
1999
2001
2003
2005
2007
2009
2011
2013
2015
Precipitation (mm)
Rainfall Snowfall
Precipitation Change in Western Himalaya