Eastern Himalayan Glaciers and Climate Change

MINGMA THUNDU SHERPA

After the influential IPCC reports which stated that “using current climate change trends, by 2100, the average global temperature mayrise by 1.4 – 5.8⁰C….” (IPCC, 2001); there has been almost a tenfold increase in the research and awareness activities so as to help the policy makers to develop strategies to control glacier retreat and control the climatic variability in the Himalayan ecosystem. 70% of the worlds freshwater are frozen in glaciers. During the dry seasons, these glaciers are the only source of fresh water to entertain and facilitate life in the biosphere. Freshwater is a limited source and might pose a serious worry about availability in future decades. The Himalayas are referred to as the “Water Tower of Asia” as it has the largest concentration of glaciers covering more than 33,000 km² other than the polar caps and annually it provides approximately 8.6 x 10⁶ m³ of water for the largest populated continent of the world as it is the ultimate source of Asia’s seven great rivers: The Ganges, Indus, Brahmaputra, Yangtze, Huang Ho, Salween and Mekong.

As per the literature reports, till date there has been at least 17 major glaciations in the past 1.6 million years and usually glaciations are followedby ‘interglacial’ periods, during which the glacier ice retreats as a result of global warming. Glacial cycles are periodically interrupted by relatively short periods of localized cooling and warming,during which glaciers advance and retreat. The most recent cooling episode of the presentinterglacial commonly referred to as the ‘Little Ice Age’ (LIA), affected parts of North America, Asia and Europeduring 1550-1850 AD.The present scenario at this crucial juncture of 21^st century have witnessed glacier retreats in almost all of the alpine regions of the globe where the first phase of glacier retreat was associated with emergence from the Little Ice Age that ended in the 19th centurywhich produced a warming of 0.3ºC in the first half of the 20th century in the Northern Hemisphere. Whereas during the last 25 years, a second 0.3ºC warming pulse caused Northern Hemisphere temperatures to rise to unprecedented levels compared to the last 1,000 years. The 1990s were the warmest decade of the millennium and 1998 the hottest year of the millennium as per the global weather reports analyzed till 2001. Overall, there was a temperature rise of close to 1ºC across the continents and now during the current decade analysis it would be interesting to note the latest temperature changes in global scenario.

There are different ways to compare the changes of glacier in the Himalayas, and one of the employed methods is the microbial niche analysis and community profile studies. The change of climate is monitored by looking on the bacterial (Archae bacteria) profile on glacier, ice and soil, identifying the carbon isotopes on the algal biomass present in the cryoconite holes, ecological responses, mapping and monitoring the seasonal snow and glacier cover etc. This type of comparative research of glacier in the Eastern Himalayas is a prime important in context of global climate change is concern.

Microorganisms living under the extreme environments provide vital information about the physical and chemical limits for physiological and biological adaptability. The extreme cold habitats and their microflora in different parts of the world have gained the attention of many researchers in the recent years. In addition to survival, microbial communities in these cold environments were investigated for their diversity, biogeography, colonization, and/or biofilm formation. In contrast to the general perception, a greater degree of microbial diversity was observed in the extremely cold environments of Arctic and Antarctica.

Talking upon the study of bacterial profile in glacier retreat, the layers of distribution of bacterial community in the ice core section, which reflects the microbial response to the past climate and environmental conditions at the time of deposition. The primary colonizers are determined by the chemical and physical characteristics of the glacier. Thus the quantitative and community structural variation of microbes in ice core might not only reflect the effect of global climate and environmental changes on the microbial transportation, but also exhibit more environmental conditions occurring at the time of deposition in local region. Thus, the quantitative distribution of these glacier bacteria in ice core section perhaps reflected the changes of climate change and environment in local region.

Research in the Himalayan Cryosphere has not been done till date and requires immediate attention. From the research perspectives, Sikkim alone houses 26 glaciers namely Changme Glacier, Changsang Glacier, Chuma Glacier, East Langpo Glacier, Gyamtang Glacier, Jongsang Glacier, Jumthul Glacier, KangkyongGlacier, Lhonak Glacier, North Lhonak Glacier, Onglaktang Glacier, Rathong – Rula Glacier, South Lhonak Glacier, South Simpu Glacier, Talung Glacier, Tasha Glacier, Tasha 1 Glacier, Tenbawa Glacier, Theukang Glacier, Teesta Glacier, Toklung Glacier, Tongshong Glacier, Umaram Glacier, Yulhe Glacier and Zemu Glacier. But unfortunately only three glaciers have been extensively studied. These glaciers are part of cryospheres which encompasses all the aspect of the frozen realm, including glaciers and ice sheets, sea ice, lake and river ice, permafrost, seasonal snow and ice crystals in the atmosphere.

Out of them RathongGlacier, ZemuGlacier and LhonakGlacier are considered as important because it is the source or origin point of riversRangit and Teesta. Most of the researchers focused on these three glaciers, whereas the remaining glaciers have not been well studied as it might be due to its dangerous topography and inconvenience of transportation. Himalayas come under seismic zone, due to the ongoing seismic activity and high rain fall it is subjected to intense cyclonic activity leading to the destruction of glaciers. Also rapid changes in temperature and intensive precipitation may lead to avalanches, rapid melting of glacier ice and snow cap, which results in the drying of natural lakes and hence is dangerous for future of Sikkim and neighboring areas of West Bengal and Bangladesh at large.

Many research works are already going on and had been undertaken by many researchers and research institutes, but the inter-disciplinary aspect and the approximate date regarding the change of glacier retreat is currently lacking. Due to poor policy and lack of appropriate research and hydrothermal water distribution strategies on this field, our water resources are depleting day by day and the downstream population is facing serious problem. Sikkim University is working on the project “Cryosphere and Science” in an inter-disciplinary manner on glacier retreat of Eastern Himalaya which is fully funded by the Department of Science and Technology, Govt. of India. This type of research is important in the context of climate change, as only one aspect of research is difficult to monitor the climate change in a particular area. So today most of the research needs inter-disciplinary aspects.

[The writer is a Junior Research Fellow IUCCCC- Project on Himalayan Cryosphere, Sikkim University]