Collaborative Research: Climate and Glacier change in Bhutan: the last millennia, present and future

DESCRIPTION: 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.