1 Asia-Pacific Symposium on new technologies for prediction and mitigation of sediment disasters. Japan Society of Erosion Control Engineering (JSECE), 18-19 Nov 2009, Tokyo, Japan.

Glacial lake outburst floods risk reduction activities in Nepal

Samjwal Ratna BAJRACHARYA sabajracharya@icimod.org

International Centre for Integrated Mountain Development (ICIMOD) PO Box 3226 Kathmandu Nepal

Abstract:

The global temperature rise has made a tremendous impact on the high mountainous glacial environment. In the last century, the global average temperature has increased by approximately 0.75 °C and in the last three decades, the temperature in the Nepal Himalayas has increased by 0.15 to 0.6 °C per decade. From early 1970 to 2000, about 6% of the glacier area in the Tamor and Dudh Koshi sub-basins of eastern Nepal has decreased. The shrinking and retreating of the Himalayan glaciers along with the lowering of glacier surfaces became visible after early 1970 and increased rapidly after 2000. This coincides with the formation and expansion of many moraine-dammed glacial lakes, leading to the stage of glacial lake outburst flood (GLOF). The past records show that at least one catastrophic GLOF event had occurred at an interval of three to 10 years in the Himalayan region. Nepal had already experienced 22 catastrophic GLOFs including 10 GLOFs in Tibet/China that also affected Nepal. The GLOF not only brings casualties, it also damages settlements, roads, farmlands, forests, bridges and hydro-powers. The settlements that were not damaged during the GLOF are now exposed to active landslides and erosions scars making them high-risk areas.

The glacial lakes are situated at high altitudes of rugged terrain in harsh climatic conditions. To carry out the mitigation work on one lake costs more than three million US dollars. In Nepal, 18 lakes were already identified as potentially dangerous and more than 70 lakes are growing in size, which might be dangerous in the future. Hence to carry out the physical mitigation works on these lakes are impractical, but creating awareness and bringing adaptation measures can effectively reduce the GLOF risk.

1. Introduction

The glaciers work as a water tower for fresh water supply as well as repository of information for exploring quaternary climate changes as they remain sensitive to global temperature conditions (Houghton and others 2001, Oerlemans 1994). Nepal houses 3,252 glaciers and 2,323 glacial lakes. Due to the impact of global warming, glaciers are melting rapidly (Fujita and others 2001, Bajracharya and others 2006, 2007), resulting in the decrease of ice mass balance and formation and expansion of substantial number of glacial lakes behind the loose moraine (Watanabe and others 1994). The rapid accumulation of water in such lakes can lead to a sudden breach of unstable moraine dams. The result is a discharge of huge amount of water and debris—GLOF—that often have catastrophic effects downstream presenting a serious hazard to the populated mountain regions. A number of GLOFs have been reported in the region in the last few decades, particularly from the eastern region (Mool and others 2001, Yamada 1998, Richardson & Reynolds 2000, Bajracharya and others 2007). The ICIMOD identified 20 such lakes as potentially dangerous in 2001; however, two lakes have been removed from the danger list (Bajracharya 2007). In 2000 physical mitigation work was carried out in Tsho Rolpa by reducing the water level by three meters (m) that cost almost US$ 3 million. To mitigate the GLOF risk,

2

the water level should be reduced by 20 m in successive phases. Due to harsh climatic conditions in high altitude, rugged terrain, remoteness with difficult access, it became expensive and impossible to complete the project. Alternative solutions that are reliable and applicable to Nepal should be identified.

2. Study Area

Nepal opened its borders to foreigners only after 1950, and therefore there were no studies conducted on glaciers and glacial lakes before then. In the early 1960 to 1970, some studies were initiated by foreign scientists and Nepalese professionals became involved only after the Dig Tsho GLOF in 1985. Until 2000, only very scanty and sporadic information of glaciers and glacial lakes of Nepal were available. The information of glaciers and glacial lakes are imperative to comprehend global warming and to reduce GLOF risk in the Hindu Kush-Karakoram-Himalayan (HKKH) region. The ICIMOD with partner institutes and in collaboration with United Nations Environment Programme (UNEP) studied glaciers and glacial lakes in Nepal from 1999 to 2001, and revealed that there are approximately 3,252 glaciers and 2,323 glacial lakes (Mool and others 2001). Most of the glaciers are above 5,000 m above sea level (masl) however, the snouts of the moraine-covered glaciers are extending down to 4,200 masl. The rapid melting and retreating of moraine-covered glaciers aided in creating large and rapidly growing glacial lakes (Bajracharya and others 2007 and 2009, Bolch and others 2008a, Kadota and others 2000). The glacial lakes were mapped from the elevation 3,500 to 5,600 masl (Mool and others 2001, Bolch and others, 2008b) and identified potentially dangerous glacial lakes are from the altitude 4,200 to 5,200 masl (Bajracharya and others 2004, Richardson & Reynolds 2000, Benn and others 2000, Yamada & Watanabe 1998, Watanabe and others 1994).

3. Global Climate Change

As mentioned earlier, in the last century, the global average temperature has increased by approximately 0.75 °C (IPCC 2001), and in the last three decades, the temperature in the Nepal Himalayas had increased by 0.15 to 0.6 °C per decade (Shrestha and others 1999), which is two to eight fold higher than the global average temperature. In the recent decades, there has been a significant increase in the global average temperature. Each year is recorded as hottest year since 1987 on the global record from 1880 to present (Ekwurzel 2006, IPCC 2007, the Independent 2007).

Most climate models show that a doubling of pre-industrial emission of greenhouse gases is very likely to raise the temperature of the earth between 2 to 5 °C in global mean temperatures between 2030 and 2060 (IPCC 2007). Several new studies suggest up to a 20% chance that warming could be greater than 5°C. If annual greenhouse gas emissions remained at the current level, concentrations would be more than treble pre-industrial levels by 2100, raising the temperature of earth by 3 to 10°C, according to the latest climate projections (Stern review 2007).

4. Glacier Retreat

The climate variability and global climatic change has brought tremendous impact on the high mountainous glacial environment (Bajracharya and others 2006 & 2008, Houghton and other 2001 and Oerlemans 1994). As mentioned earlier, from 1970 to 2000, approximately 6% of glacier areas have decreased in the Tamor and Dudh Koshi sub-basins of eastern Nepal (Bajracharya 2006, 2009). Since the early 1970 and more rapidly after 2000, the Himalayan glaciers are shrinking and retreating and the glacier surface are lowering (Bajracharya and others 2009, Fujita and others 2001, Khromova and others 2003, Paul 2002, Paul and others 2004). For example, the AX010 Glacier of Mt. Everest region is shrinking at all sides with the fear of it disappearing by 2060 (Asahi and others 2006); the Valley glaciers in the Mt. Everest region are retreating at a rate of 10 to 60 m per year on average; and the

3 Asia-Pacific Symposium on new technologies for prediction and mitigation of sediment disasters. Japan Society of Erosion Control Engineering (JSECE), 18-19 Nov 2009, Tokyo, Japan.

Imja Glacier has been retreating at a rate as high as 74 m per year since 2001 (Bajracharya and others 2007).

5. Potentially Dangerous Glacial Lakes

In 2001, a study by ICIMOD and UNEP identified 2,323 glacial lakes out of which 20 lakes are identified as potentially dangerous (Figure 1); however, two lakes were removed from the danger list as the area of the lakes has been reduced drastically due to outburst (Bajracharya 2007, 2008, 2009). As an impact of global warming, 50 lakes are growing and 22 new lakes have been formed after 2000 (Bajracharya 2005, 2006) (Table 1). If the lakes continue to form and grow in the present trend with respect to the climate change it is anticipated that the number of potentially dangerous glacial lakes will increase with a high possibility of GLOF in the near future.

6. Glacial Lake Outburst Flood Disaster

The glacial lake outburst flood is an inherent part of glaciers and the glacial lakes. In some instance, the glacier snout area and down valley is favorable in the formation of lakes. The continuous and enhanced retreat of glaciers due to global climate change resulted the formation, expansion and merging of many glacial lakes behind the unconsolidated moraine at the toe of glaciers. The rapid accumulation of water in these lakes can lead to a sudden breach of their unstable dams causing GLOF (Boltch and others 2008b, Watanabe and others 1994, Bajracharya and others 2005, Hambrey and others 2008). The GLOF often have catastrophic effects downstream and pose a severe hazard to mountain communities.

Figure 1: Distribution of potentially dangerous glacial lakes in Nepal.

China 

Nepal 

India 

4

The past record shows that at least one catastrophic GLOF event had happened at an interval of three to 10 years in the Himalayan region. Related disasters repeatedly caused casualties; for instance, farmland was inundated and destroyed, micro-and macro-hydro-power schemes damaged or bridges torn down, often in less-developed regions where these infrastructures are urgently needed, and seldom established through development activities. In particular, the population living in the harsh mountain reality suffers from these in the short-and long-term through environmental and socio-economic hazards. Nepal had already experienced 22 catastrophic GLOFs including 10 GLOFs in Tibet/China damaging inside Nepal (Table 1) (Bajracharya and others 2007, Mool 1995, Mool and others 2001, Reynolds 1998, Yamada 1998 and 2000, Yamada and Sharma 1993). The Zhangzangbo GLOF of 1981 in Tibet (China) did a lot of damage in Tibet (China) and Nepal. It even caused severe damage to sections of the Nepal–China Highway including wash out of three bridges. The Dig Tsho GLOF in 1985 in the Dudh Koshi sub-basin damaged the Namche hydropower station, 14 bridges, cultivated lands and many more (Vuichard and Zimmerman 1987).

Table 1 Status of Glacial Lakes and GLOF in Nepal

_______________________________________________________________________ Number of Glacial Lakes 2323 Total Glacial Lake area 75 sq km Glacial Lakes larger than 0.02 sq km in area

− Total number 411 − Associated with mother glaciers 347 − Distance less than 1 km 330

Growing Glacial Lakes 50 Glacial Lakes formed after 2000 22 Potentially dangerous Glacial Lakes 20 GLOF in Tibet/China damage inside Nepal 10 GLOF in Nepal 12

_________________________________________________________________________ The damaging phenomenon occurs at the river valley sides of high altitude where the harsh climatic condition allows very slow growth of vegetation. Once the slope is disturbed by the GLOF, the slope remains unstable due to high erosive nature of rain, snow and wind than the natural slope stabilisation. Hence the undamaged settlements, landforms and infrastructure during the GLOF are now exposed to the active landslides and erosion scars (Figure 2) making this a high-risk area. The damage caused by GLOF is not a one-time occurrence; it is followed by continuous erosion phenomena with the threat of danger throughout the year.

.

a. Namche micro-hydropower site

damaged by Dig Tsho GLOF b. Dig Tsho dam breach in 1985 c. Marginal settlements

Figure 2. The Dig Tsho GLOF happened in 1985 but the damage is continuous throughout the year.

1986 2007 2007

5 Asia-Pacific Symposium on new technologies for prediction and mitigation of sediment disasters. Japan Society of Erosion Control Engineering (JSECE), 18-19 Nov 2009, Tokyo, Japan.

7. GLOF Risk Reduction Activities

Almost all of the dangerous and growing glacial lakes are situated at remote and high altitudes of rugged terrains with harsh climatic conditions. Hence to carry out the physical mitigation works on these lakes are expensive and impractical, but awareness and adaptation measures can be carried out to reduce the GLOF risk. As a pilot case study, GLOF risk reduction activities were carried out in the Everest region downstream of Imja Tsho, one of the fastest growing lakes in the Himalayas.

To understand and reduce the GLOF hazard and risk, and strengthen the mountain people’s resilience, ICIMOD had studied the glaciers, glacial lakes and GLOFs in the Hindu Kush-Himalayan region. The study is continued successively by using simulation of GLOF, vulnerability and risk assessment, near real-time monitoring, real-time monitoring, networking of field sensor and transmission station, rural wireless internet connectivity and possible mitigation measures in the Everest region in 2008. Simulation of GLOF Using the Dam Break and HEC Ras models possible extension of debris flow, flood depth and time travel of the debris and nature of flood propagation in the downstream was derived from the hydrodynamic modeling. The spatial distribution of the flood was analysed by preparing inundation

Table 2: GLOF events that have occurred affecting inside Nepal No. Date River basin Lake Latitude Longitude

TAR China 1 Aug 1935 Sun Koshi Tara-Cho 28° 17’ 00” 86° 08' 00” 2 21 Sept 1964 Arun Gelhaipco 27° 58' 00” 87° 49' 00” 3 1964 Sun Koshi Zhangzangbo 28° 04' 01” 86° 03' 45” 4 25 Aug 1964 Trisuli Longda 28° 37’ 01” 85° 20’ 58” 5 1968 Arun Ayaco 28° 21’ 00” 86° 29' 00” 6 1969 Arun Ayaco 28° 21’ 00” 86° 29' 00” 7 1970 Arun Ayaco 28° 21' 00” 86° 29' 00” 8 11 Jul 1981 Sun Koshi Zhangzangbo 28° 04' 01” 86° 03' 45” 9 27 Aug 1982 Arun Jinco 28° 00' 35” 87° 09' 39”

10 6 Jun 1995 Trisuli Zanaco 28° 39’ 44” 85° 22’19” Nepal

11 About 450 years ago Seti Khola Machhapuchhre 28° 31' 13" 83° 59' 30" 12 3 Sept 1977 Dudh Koshi Nare 27° 49' 47" 86° 50' 12" 13 23 Jun 1980 Tamor Nagma Pokhari 27° 51' 57" 87° 51' 46" 14 4 Aug 1985 Dudh Koshi Dig Tsho 27° 02' 36" 86° 35' 02" 15 12 Jul 1991 Tama Koshi Chhubung 27° 52' 37" 86° 27' 38" 16 3 Sept 1998 Dudh Koshi Tam Pokhari 27° 44’ 20” 86° 50’ 45” 17 Unknown Arun Barun Khola 27° 50' 33" 27° 50' 33" 18 Unknown Arun Barun Khola 27° 49' 46" 87° 05' 42" 19 Unknown Dudh Koshi Chokarma Cho 27° 54’21” 86° 54’48” 20 Unknown Kali Gandaki Unnamed 29° 13' 14" 83° 42' 09" 21 Unknown Kali Gandaki Unnamed 29° 07’03" 83° 44' 19" 22 Unknown Mugu Karnali Unnamed 29° 39’00” 82° 48’00”

6

maps for the high flood level along the river (Table 3). This table helps to estimate the arrival time of the flood, which is useful in reducing the GLOF risk. The result needs to be verified, and if it is closure to the reality this type of simulation can be replicated with some modification in other potentially dangerous glacial lakes of the Himalaya

Table 3: Estimated flood arrival time and discharge from Imja GLOF Place Chainage (Km) Time (min) Discharge (m3S-1) Flood depth (m)

Imja lake outlet 0.0 0.0 5461 Dingboche 7.52 13.9 5094 5.8 Orso 11.55 18.8 4932 5.5 Pangboche 13.65 21.3 4800 7.6 Larja Dovan 25.94 34.8 3223 6.9 Bengkar 29.67 38.8 2447 6.6 Ghat 34.58 48.4 2355 5.8

GLOF Vulnerability and Risk Assessment The vulnerability of an area to a GLOF is assessed by calculating the probability of a direct or indirect hit by the GLOF. The GLOF vulnerability assessments of the downstream valley along Imja Tsho were carried out through visual inspections, walkover surveys and additional information used from the modeling and flood routing along the river valley. Most of the major settlements, infrastructure and trekking routes are at lower terraces of GLOF risk area (Figure 3). The analysis of possible lateral or bed erosion and sedimentation from Imja Tsho to Larja Dovan were estimated by comparing data from the Langmoche valley (which experienced a GLOF in 1985). The Larja Dovan is the confluence of the streams from the Lakes Dig Tsho and Imja Tsho. The area downstream from Larja Dovan has already experienced the Dig Tsho GLOF; an additional GLOF event in this valley would be more catastrophic. The landslides that were generated from 1985 GLOF is still active in Ghat and Phakding. A new GLOF event could trigger new instabilities in many places and reactivate the old ones. The vulnerability and risk assessment result will be helpful in planning and developing the area as well as to create awareness among the people living in the downstream to reduce the GLOF risk.

a. Possible GLOF impact in Dingboche village b. Field photograph

Figure 3 :GLOF Vulnerability assessment along the downstream of Imja Tsho

Near real-time monitoring The glaciers are retreating and the lakes associated with the glaciers are rapidly increasing in size and number in recent decades. Up-to-date database of the glaciers and glacial lakes are of utmost importance to understand the glaciers and glacial lakes activities, which is only possible to through satellite images. Clouds can be a major hindrance to satellite imaging particularly during the monsoon season in the visible and infrared remote sensing range. Information missed due to cloud cover cannot be retrieved and is then accessible only by field observation, which is not possible to cover for all regions. An alternative solution is microwave remote sensing. Since microwave sensing can penetrate cloud cover, it is independent of weather conditions and is thus suitable for year-round monitoring of glacial lakes. Since 2007, ICIMOD

7 Asia-Pacific Symposium on new technologies for prediction and mitigation of sediment disasters. Japan Society of Erosion Control Engineering (JSECE), 18-19 Nov 2009, Tokyo, Japan.

with support from European Space Agency (ESA), Synthetic Aperture Radar (SAR) and Advanced Synthetic Aperture Radar (ASAR) data are being used to monitor the growth of Imja Tsho and its vicinity (Figure 4). The RADAR can be used to monitor as often as monthly.

CORONA 15 Dec 1962 Space Shuttle Dec 1983 LANDSAT TM 1992 ENVISAT, ASAR, Oct 2007

Figure 4: Growth of Imja Tsho from 1962 to 2007. Real-time monitoring ICIMOD identified many potentially dangerous glacial lakes in the Himalayas and Imja Tsho is one of the fastest growing lakes in the entire Himalayan region. Scientific studies and regular monitoring of growing lakes is of utmost importance to prevent potential GLOF hazards. With the cooperation of Department of National Park and Wildlife Conservation (DNPWC) and Keio University of Japan, ICIMOD is aiming to regularly monitor and devise an early warning system using remote sensing, geo-ICT tools and techniques in the Imja Tsho (Figure 5). The collected information like lake water level, total weather station and photographs collected from the web camera transmits through the stations to local Internet Service Provider (ISP) in Namche bazaar to upload to. This information is processed, scanned, filtered and again uploaded into the website by Asian Institute of Technology (AIT) (http://fsds.dc.affrc.go.jp/data4/Himalayan) for stakeholders to view.

Figure 5: Networking of transmit station and field sensors to nearest ISP in Namche Bazar.

Rural wireless Internet connectivity The installation of networking of field sensor and transmission station can facilitate to commission local area WIFI with the possibility to connect with national telecom network and provide rural connectivity and access to information. Wireless Internet facilities are provided by Keio University at Chhukung, Pangboche, Tengboche and Dingboche Villages and further could be added in other GLOF risk area. The services will be limited within the area where networking of field sensors and transmission stations are available.

8

Create global and local awareness

ICIMOD and Asian Trekking jointly organised the Eco Everest Expedition 2008 program. Under this program, different climate change awareness activities were carried out at the Information Centre at Everest Base Camp from 12 April to 12 June 2008. The program included photographs of Himalayan glaciers taken in last 50 years (Figure 6); message from the Director General of ICIMOD read by Dawa Steven Sherpa and demonstrations of eco-friendly alternative energy.

Message: “Let us care for Environment of Himalaya & strengthen its people’s determination and resilience”

a: 1956: Fritz Muller; courtesy of Jack Ives Figure 6: 50 Years repeat photographs of Imja glacier.

b: 2006: Giovanni Kappenberger courtesy of A. Byers

GLOF Awareness Workshop was organised for the local people in Namche Bazaar (point of

entry to Mt. Everest) on “Climate change impact in the Himalaya: Glacial Lake Outburst Flood (GLOF)” on 25 April 2008 with the contribution of Appa Sherpa, 18-times Mt. Everest summiteer, Dawa Steven Sherpa, leader of Eco Everest Expedition, Japanese team from Keio University and NHK TV team, ICIMOD experts, local media people, senior citizens and about 50 local people (Figure 7).

Figure 7: Glacial lake outburst flood (GLOF) awareness workshop in Namche Bazar.

9 Asia-Pacific Symposium on new technologies for prediction and mitigation of sediment disasters. Japan Society of Erosion Control Engineering (JSECE), 18-19 Nov 2009, Tokyo, Japan.

Early warning systems Early warning systems aim to detect impending GLOFs in sufficient time to relay a warning to people who might be affected so that they can move to safer grounds. In 1997, the meteor burst early warning system with duel function of receiver and transmitter was installed in Tsho Rolpa Lake and its downstream areas. Due to poor maintenance and lack of ownership, the system worked for only a couple of years and now not a single set exist in the field. For effective and practical use of early warning systems, an information technology (IT) based system with clear ownership guideless are necessary. The use of geo-ICT tools and techniques will be a state-of-the-art in the region and the Internet connectivity will be the backbone to the overall system. The web-based early warning system can be developed at ICIMOD and disseminated through the Internet and can be replicated in other basins of potentially dangerous lakes. This type of system is innovative in nature and will be first-of-its kind in the Himalayan region. It is necessary to develop awareness and capacity of the local people who now have access to wireless Internet, but not in full capacity.

Encourage development activities in less GLOF risk area The Everest region is one of the most popular tourist destinations and hence many hotels, lodges and other infrastructures linger near or along the trekking route. Most of the trekking routes are along the riverbanks at lower terraces that might be easily washed out in case of GLOF. To reduce GLOF risk, it is necessary to discourage or stop development activities in GLOF risk area and encourage shifting and development of new activities only in the low GLOF risk areas.

Safe breaching of potentially dangerous glacial lakes to reduce GLOF risk and water resources management A study conducted by ICIMOD and UNEP identified 18 potentially dangerous glacial lakes with 50 lakes that are currently being formed and 22 lakes that are newly formed in Nepal. The number of dangerous glacial lakes may increase with the pace of global warming. To reduce the Tsho Rolpa GLOF risk, in 2000, 3 m of water level was reduced by constructing about 70 m long, 6.4 m wide and 4.2 m deep canal at the end moraine that cost approximately US$ 3 million. This reduced the danger level of the lake temporarily for some years, but the overall structure is resting over loose moraine that will create a havoc if hit by an earthquake. Nepal is situated in an earthquake-prone zone, where many small and high-scale earthquakes are predicted in the region. The loose moraine will be unstable even it is hit by a smaller earthquake. In the context of Nepal, it is not feasible to spend large sums of money on uncertain projects, and it is not recommended to construct any civil structure on the moraine itself for mitigation work. The most permanent, safe and cheap methods for mitigation work is needed, which is possible by safe breaching moraine dams before the settlements begin with the safeguard of many check dams and an earth dam at stable and narrow river valley downstream of the lake for new reservoir This will reduce not only the GLOF risk but can be managed the water resources for the hydropower, water supply for drinking and irrigation etc. which will improve the livelihood of the mountain people. 8. Conclusions

In the period of 30 years from 1970 to 2000, there has been about 6% of glacier area loss in eastern Nepal and an increase in the glacier retreat in the recent decade. The immediate impact of fast and continuous retreat of glaciers is the proliferation of moraine dammed glacial lakes. The continuous growth of the lake ultimately leads to the breaching of the moraine dam with catastrophic GLOF. The region had already experienced many GLOF events with continuous erosion and instability of slopes consequently threatening settlement. The rapid growing glacial lakes will most likely pose danger in the future and therefore it is vital that these glaciers and glacial lakes are monitored for the sound management of water resources and disaster risk reduction. Instead of constructing physical mitigation structure on the unstable moraine and earthquake prone zone, it will be more feasible to create awareness for the adaptation and safe breaching of the moraine dam. However, the phenomenon is a

10

challenge with limits imposed by the higher altitude, rarefied atmosphere, remoteness of many of the locations and short working season due to near-freezing temperatures in the area.

9. Acknowledgements

The author is grateful to Basanta Shrestha and Pradeep Mool from ICIMOD for their support and cooperation in preparing this document.

10. References Asahi, K., T. Kadota, N. Naito, and Y. Ageta 2006. Variations of small glaciers since the 1970s to 2004

in Khumbu and Shorang regions, eastern Nepal’ Data Report 4 (2001-2004). Glaciological Expedition in Nepal (GEN) and Cryosphere Research in the Himalaya (CREH). Graduate School of Environmental Studies, Nagoya University and Department of Hydrology and Meteorology, HMG of Nepal. 109 – 136.

Bajracharya, S. R. and P. K. Mool 2009. Glaciers, glacial lakes and glacial lake outburst floods in the Mount Everest region. Nepal. Annals of Glaciology, 50 (53) London, UK. 81 – 86.

Bajracharya, S.R., P.K. Mool and B. R. Shrestha 2008. Global climate change and melting of Himalayan glaciers. In Ranade, P.S., ed. Melting glaciers and rising sea levels: impacts and implications, Hyderabad, India, Icfai University Press, 28–46.

Bajracharya, S.R., P.K. Mool and B.R. Shrestha 2007. Impact of climate change on Himalayan glaciers and glacial lakes: case studies on GLOF and associated hazards in Nepal and Bhutan. ICIMOD and UNEP, 119.

Bajracharya, S. R., P. K. Mool, B. R. Shrestha 2006. The impact of global warming on the glaciers of the Himalaya. In Proceedings of the International Symposium on Geodisasters, Infrastructure Management and Protection of World Heritage Sites, 25-26 Nov 2006, Kathmandu: Nepal Engineering College, National Society for Earthquake Technology Nepal, and Ehime University Japan, 231-242.

Bajracharya, S.R. and P.K. Mool 2005. Growth of hazardous glacial lakes in Nepal. In Yoshida, M., B.N. Upreti, T.N. Bhattarai and S. Dhakal, eds. International Seminar on Natural Disaster Mitigation and Issues on Technology Transfer in South and Southeast Asia – JICA Regional Seminar, 30 September to 13 October 2004. Proceedings, Kathmandu, Nepal, Tribhuvan University, Tri-Chandra Campus, Department of Geology with Japan International Cooperation Agency (JICA), 131–148.

Bajracharya, S.R., and P.K. Mool 2004. Potential glacial lake outburst floods from major glacial lakes in Nepal in the event of a large earthquake. Seminar and Workshop on the Potential for Landslides in Nepal in the Event of a Large Earthquake, 4–6 August 2004, Kathmandu, Nepal. Proceedings, Kathmandu, Nepal, Tribhuvan University, Mountain Risk Engineering Unit and University of Durham, U.K., 1–10.

Benn, D., S. Wiseman, and C. Warren 2000. Rapid growth of a supraglacial lake, Ngozumpa Glacier, Khumbu Himal, Nepal. Debris-Covered Glaciers, IAHS 264: 177-186.

Bolch, T., M. F. Buchroithner, T. Pieczonka, and A. Kunert 2008a. Planimetric and volumetric Glacier changes in Khumbu Himalaya since 1962 using Corona, Landsat TM and ASTER data’. Journal of Glaciology 54(187): 9.

Bolch, T., M.F. Buchroithner, J. Peters, M. Baessler and S. Bajracharya 2008b. Identification of glacier motion and potentially dangerous glacial lakes in the Mt. Everest region/Nepal using spaceborne imagery. Natur. Hazards Earth Syst. Sci. (NHESS), 8(6), 1329–1340.

Ekwurzel, B., 2006. Expected impacts of climate change in the U.S. Urban leaders initiative on infrastructure, Land use and climate change, Center of Clear Air Policy and Union of Concerned Scientists.

Fujita, K., T. Kadota, B. Rana, R.B. Kayastha and Y. Ageta 2001. Shrinkage of Glacier AX010 in

11 Asia-Pacific Symposium on new technologies for prediction and mitigation of sediment disasters. Japan Society of Erosion Control Engineering (JSECE), 18-19 Nov 2009, Tokyo, Japan.

Shorong region, Nepal Himalayas in the 1990s. Bull. Glaciol. Res., 18, 51–54. Hambrey, M.J., D.J. Quincey, N.F. Glasser, J.M. Reynolds, S.J. Richardson and S. Clemmens 2008.

Sedimentological, geomorphological and dynamic context of debris-mantled glaciers, Mount Everest (Sagarmatha) region, Nepal. Quat. Sci. Rev., 27(25–26), 2361–2389.

Houghton, J.T. and 7 others, eds. 2001. Climate change 2001: the scientific basis, Cambridge, etc., Cambridge University Press. Intergovernmental Panel on Climate Change. (Contribution of Working Group I to the Third Assessment Report.)

IPCC Third Assessment Report 2001 - Climate change 2001: Working Group I, the scientific basis, Cambridge University Press. Intergovernmental Panel on Climate Change.

IPCC Fourth Assessment Report 2007 – Climate Change 2007: Working Group 1, The Physical Science Basis, Summary for Policymakers. (http://ipcc-wg1.ucar.edu/wg1/wg1-report.html).

Kadota, T., K. Seko, T. Aoki, S. Iwata and S. Yamaguchi 2000. Shrinkage of Khumbu Glacier, east Nepal from 1978 to 1995’ IAHS Publication 264: 235-243.

Khromova, T.E., M.B. Dyurgerov and R.G. Barry 2003. Late-twentieth century changes in glacier extent in the Ak-shirak Range, central Asia, determined from historical data and ASTER imagery. Geophys. Res. Lett., 30(16), 1863. (10.1029/2003GL017233.)

Mool, P.K., S.R. Bajracharya and S.P. Joshi 2001. Inventory of glaciers, glacial lakes and glacial lake outburst floods: monitoring and early warning systems in the Hindu Kush–Himalayan region: Nepal. Kathmandu, Nepal, International Centre for Integrated Mountain Development (ICIMOD) with United Nations Environment Programme/Regional Resource Centre for Asia and the Pacific.

Mool, P.K. 1995. Glacier lake outburst floods in Nepal. J. Nepal Geol. Soc., 11, Special Issue, 273–280. Oerlemans, J. 1994. Quantifying global warming from the retreat of glaciers. Science, 264(5156), 243–

245. Paul, F., A. Kääb, M. Maisch, T. Kellenberger and W. Haeberli 2004. Rapid disintegration of Alpine

glaciers observed with satellite data. Geophys. Res. Lett., 31(21), L21402. (10.1029/2004GL020816.)

Paul, F. 2002. Combined technologies allow rapid analysis of glacier changes. Eos, Trans. AGU, 83(23), 253, 260–261.

Richardson, S.D. and J.M. Reynolds 2000. An overview of glacial hazards in the Himalayas. Quat. Int., 65–66, 31–47.

Shrestha, A.B., C.P. Wake, P.A. Mayewski, J.E. Dibb 1999. Maximum Temperature Trends in the Himalaya and its Vicinity: An Analysis Based on Temperature Records from Nepal for the Period 1971-94. In Journal of Climate, 12: 2775-2767.

Stern review 2007. The economics of climate change. www.sternreview.org.uk the Independent (U.K.) Jan. 1, 2007. May Be Hottest Year On Record.

http://www.heatisonline.org/contentserver/objecthandlers/index.cfm?id=6209&method=full Vuichard, D. and M. Zimmermann 1987. The 1985 catastrophic drainage of a moraine-dammed lake,

Khumbu Himal, Nepal: cause and consequences. Mtn Res. Dev., 7(2), 91–110. Watanabe, T., J.D. Ives and J.E. Hammond 1994. Rapid growth of a glacial lake in Khumbu Himal,

Himalaya: prospects for a catastrophic flood. Mtn Res. Dev., 14(4), 329–340. Yamada, T. 2000. Glacier lake outburst floods in Nepal. Seppyo, J. Jpn. Soc. Snow Ice, 62(2), 137–

147. [In Japanese with English summary.] Yamada, T. & O. Watanabe, Eds. 1998. Glacier lake and its outburst flood in the Nepal Himalaya.

Monographs of Data Center for Glacier Research. Tokyo. Yamada, T. and C.K. Sharma 1993. Glacier lakes and outburst floods in the Nepal Himalaya. IAHS

Publ. 218 (Symposium at Kathmandu 1992 — Snow and Glacier Hydrology), 319–330.