Environmental Change in the Himalayas impacts societies in the most densely populated area on Earth. Rapid glacier retreat in the monsoonal Himalayas affects river discharge, energy production, and agriculture. A serious threat is posed by outburst floods from glacial lakes in the Himalayan country of Bhutan. Bhutan's welfare is directly linked to glacier dynamics because the country's primary source of income, exported hydropower, as well as the national agricultural irrigation infrastructure, are fueled by glacier melt. Melting glaciers and the steep relief have made outburst floods a prime hazard for Bhutan and their Himalayan neighbors, and the hazard potential depends on current and future glacier melt. Determining the rate of glacier retreat in response to climate change is fundamental for predicting future flood probabilities and for designing adaption and mitigation strategies for Bhutanese society. Currently the rate of glacier retreat is very poorly constrained. This EAGER proposal seeks funds to take the first step towards providing robust information about past, present and future glacier and climate change in Bhutan, and in turn contribute to a more robust scientific data for decision makers and mitigation strategists.
The identified target area for this EAGER project is Rhapstreng Glacier, in the Lunana area of Bhutan. Over the last decade the PIs have established connections to the scientific and political leadership in Bhutan, in particular with the Department of Energy/Ministry of Economical Affairs and the Ugyen Wangchuck Institute for Conservation and Environment (UWICE), and have also identified excellent climate and environmental records: (i) Outstanding past glacier records, consisting of well-preserved moraine sequences; (ii) Conifer tree species which will allow the PIs to reconstruct climate, especially summer temperature, back through the Little Ice Age and into late-Medieval times; (iii) Bhutanese glaciers that are, according to preliminary mass balance modeling in the Himalaya, particularly sensitive to changes in temperature as compared to precipitation, making them excellent targets for more refined glaciological modeling, and making the tree-ring reconstructions particularly useful to the glacier reconstructions.
The grant supports a concerted field campaign, including geomorphology, geochronology, paleothermometry, and glaciology in order to lay the foundation for reconstructing glacier histories and climate change over the last millennia, and to better predict Himalayan glacier change over the next centuries. The PIs have assembled a multidisciplinary team of experts with broad experience in Himalayan glacier and climate problems, including a female junior faculty at a primarily undergraduate university. This EAGER proposal is the first step towards a bilateral educational program, including bilateral student exchange between CU and UWICE and integration of Bhutanese students in annual field campaigns.
This EAGER awards was successfully used to organize the first major US-lead expedition to glaciers in Bhutan. In september 2012, an expedition including researchers from Lamont/Columbia University (glacial geology and geochronology, tree ring science), Brigham Young University (glaciology) and the Department of Hydromet Services, Ministry of Energy, Bhutan, took part in the expedition to reach the Rinchen Zoe Glacier system, which took about a 7 day extreme hike one way. The Rinchen Zoe Glacier system at about 5200 m altitude, was carefully mapped, equipped with glaciological stakes to measure the modern ice flow, and the highest moraines were sampled for cosmogenic 10Be surface exposure dating. In parallel, the tree ring crew collected samples from trees close to the moraines, and preliminary studies show that these samples afford for temperature reconstructions over at least 500 years. The EAGER awards also afforded the first glacier-climate publication, lead by the US researchers but including colleagues from Bhutan (Rupper et al., 2012). This EAGER awards also formed the base for a broader NSF-funded project about Glaciers, Climate and Society in Bhutan. In summary, this EAGER awards represents an excellent example for flexible and small NSF investments, opening an entirely new field of research for the US science community, in this example, the start of a truly cross-cutting research and education program between two US universities and government and academic institutions in Bhutan. Rupper, S., Schaefer, J.M., Burgener, L.K., Koenig, L.S., Tsering, K., Cook, E.R., 2012. Sensitivity and response of Bhutanese glaciers to atmospheric warming. Geophys. Res. Lett. 39, L19503.)
