The State and Fate of Himalayan Glaciers

Abstract

Himalayan glaciers are a focus of public and scientific debate. Prevailing uncertainties are of major concern because some projections of their future have serious implications for water resources. Most Himalayan glaciers are losing mass at rates similar to glaciers elsewhere, except for emerging indications of stability or mass gain in the Karakoram. A poor understanding of the processes affecting them, combined with the diversity of climatic conditions and the extremes of topographical relief within the region, makes projections speculative. Nevertheless, it is unlikely that dramatic changes in total runoff will occur soon, although continuing shrinkage outside the Karakoram will increase the seasonality of runoff, affect irrigation and hydropower, and alter hazards.

Spatiotemporal patterns of High Mountain Asia's snowmelt season identified with an automated snowmelt detection algorithm, 1987–2016

“…This important water reserve is certain to be impacted by, and reflect changes in, the snowmelt regime of HMA, as the timing of precipitation has been shown to be an important factor in the response of glaciers to climate change (Maussion et al, 2014;Wang et al, 2017). While many regions have seen rapid glacier retreat (Bolch et al, 2012;Kääb et al, 2012Kääb et al, , 2015Scherler et al, 2011), there exist regions of glacier stability and even growth, such as the Karakoram (Hewitt, 2005;Gardelle et al, 2012) and Kunlun Shan (Gardner et al, 2013;Yao et al, 2012). Our results (see Fig.…”

“…Many regions rely on glaciers as their only water source between the end of snowmelt and the beginning of major precipitation systems (Bolch et al, 2012). This important water reserve is certain to be impacted by, and reflect changes in, the snowmelt regime of HMA, as the timing of precipitation has been shown to be an important factor in the response of glaciers to climate change (Maussion et al, 2014;Wang et al, 2017).…”

Compilation of a glacier inventory for the western Himalayas from satellite data: methods, challenges, and results

“…For the heavily glacierized region of the Himalaya all of the above purposes apply, but little information is available in digital form for a sound change assessment of these glaciers over a large region (Bolch et al, 2012). This results in high uncertainties when local observations need to be generalized (Raina, 2009).…”

“…Racoviteanu et al, 2009). For the reasons above, any derived changes in glacier area might be more artificial rather than real (Racoviteanu et al, 2009;Paul & Hendriks, 2010;Bolch et al, 2012). …”

Glacier changes on the Tibetan Plateau derived from Landsat imagery: mid-1970s – 2000–13

“…Nearly all mountain glaciers have been melting rapidly in recent decades (Gardner and others, 2013; Zemp and others, 2015) and this has been documented, especially in High Mountain Asia (HMA hereafter), in surveys of the whole ( Li and others, 2008;Cogley, 2016) or large parts (Bolch and others, 2012;Yao and others, 2012) of the region as well as in basin-scale and single-glacier studies (Fujita and Nuimura, 2011;Wang and others, 2013;Yang and others, 2013). As reported in these earlier studies, most HMA glaciers showed obvious shrinkage (area loss) and thinning (implying mass loss) except in the west, for example in the Karakoram ( Gardelle and others, 2012) and western Kunlun (Neckel and others, 2014; Kääb and others, 2015; Ke and others, 2015).…”