Future projections of glacier mass loss

In our new study published in Nature last week, we show that even if the planet only warms up by 1.5 degrees Celsius 36% of all Asian glacier ice will have melted by the end of the century. More extreme temperature scenarios, for example the ones projected by IPCC’s RCP8.5, will result in mass losses of up to 64%.

Glaciers in the high mountains of Asia play a substantial role in regional water resource and they have been losing mass over the last decades (e.g. Brun et al, 2017), a trend that is most likely to persist under future temperature rise. At the 2015 UN Climate Change Conference in Paris, 195 nations signed the “Paris Agreement” and agreed on efforts to limit the global temperature rise to 1.5 °C. It was unknown, however, how much of Asia’s ice mass would be lost under such a scenario, or under more extreme temperature scenarios.

To determine this, we have developed a glacier model for all individual Asian glaciers larger than 0.4 km2. We have forced the glacier model transiently up to 2100 by the full CMIP5 ensemble of 110 climate models, and have taken into account present-day climate, the imbalance of the glaciers, and the effect of debris cover.

Our results show that only a handful of the climate models project a global temperature rise of 1.5 °C and that the glaciers in the region warm consistently more than the global mean because of elevation dependent warming. By the end of the current century the 1.5 °C scenario results in a loss of over one third of the present-day ice mass in the region, while mass losses projected under more extreme temperature projections go up to almost two third.

We have also found that there are large regional differences in projected mass loss, which are caused primarily by regional differences in debris cover, ice mass, present-day glacier imbalance, and glacier sensitivity to climate perturbations.

 

Mass loss projections for the current century aggregated by sub-region of the Randolph Glacier Inventory v5.0. The bar charts indicate the regional prevalence of debris-covered glaciers.

 

To learn more about our study refer to the paper below, or have a look at our visual story line.

 

Impact of a global temperature rise of 1.5 degrees Celsius on Asia’s glaciers
Kraaijenbrink, P. D. A., Bierkens, M. F. P., Lutz, A. F., & Immerzeel, W. W. (2017)
Nature, 549(7671), 257-260. DOI: 10.1038/nature23878

 

New estimates of HMA glacier change

Fanny, Patrick, Etienne Berthier and colleagues from Oslo University (Andreas Kääb and Désirée Treichler) have just published the study “A spatially resolved estimate of High Mountain Asia glacier mass balances from 2000 to 2016” in Nature Geoscience. They used more than 50,000 ASTER satellite images to derive digital elevation models and to track glacier thickness changes over High Mountain Asia. They provide the first consistent estimate of volume change for ~90 000 km2 of glaciers.
 
Their study confirms the existence of the so called “Karakoram anomaly” and, following a 2015 study by Andreas Kääb et al. refines its location: glaciers located in the West Kunlun, Karakoram and Eastern Pamir have balanced or slightly positive mass changes. The most negative mass changes are found in the Eastern Himalaya, where glaciers loose mass at rates similar to the ones in the European Alps (up to 0.62 ± 0.23 m w.e. yr-1).
 

Rate of glacier elevation change (in m/yr) for the period 2000-2016. Red dots represent area where glaciers are thinning and blue dots area where glaciers are thickening.

Rate of glacier elevation change (in m/yr) for the period 2000-2016. Red dots represent area where glaciers are thinning and blue dots area where glaciers are thickening.

 

 
These data will help to constrain glacio-hydrological models and to better understand the contribution of glaciers to stream flow and sea level rise. Nevertheless, they provide only mass balance values averaged over 16 years and therefore do not give access to the processes responsible for these changes. More field data are needed to investigate these.

 

naturegeocmyk

AGU Session – Recent advances in understanding the high-mountain water cycle

We are excited about hosting a session at this year’s AGU in New Orleans. We hope to bring together a wide range of research from catchment hydrology, the cryosphere, snow hydrology and atmospheric sciences. Two invited lecturers – Dirk Scherler from GFZ and Duncan Quincey from the University of Leeds – have agreed to give insights into recent forays in their field sites in High-Mountain Asia. Deadline for submissions is the 2nd of August – we look forward to see many of you there.

Click here for details and Submission:

C028: Recent advances in understanding the high-mountain water cycle
Session Description:

High-mountain catchments play an important water supplying role and are sensitive to climate change. Yet the monitoring and modelling of such regions remains a challenge, due to poor accessibility, limited data availability and the lack of numerical models that address key cryospheric and hydrological processes in sufficient physical detail. This session brings together studies that focus on integrating observations, remote sensing and numerical models with the aim to understand present and future glacio-, hydro- and meteorological processes in mountainous regions. It focuses on advances in understanding high-altitude meteorology, feedbacks between the cryosphere and atmosphere, glacier and snow dynamics, climate change impacts and the associated hydrological response. The session welcomes in particular  studies that: i) link results from atmospheric modelling to the high-altitude water cycle, (ii) advance the process understanding of glaciers, snow and the hydrological cycle, (iv) quantify hydro-meteorological extremes, and (v) assess impacts of climate change using process-based modelling.

Walter Immerzeel Boussinesq Awardee 2017

We are pleased to announce that on Friday June 2nd Walter Immerzeel received the Boussinesq Prize 2017, a tri-annual award given to a person for recognition of his/her outstanding scientific contributions to hydrological sciences. It was awarded by prof. Bob Su at the Boussinesq Spring Meeting 2017 in Enschede. At the meeting Walter gave a keynote presentation on “Recent advances in understanding climate, glacier and river dynamics in high mountain Asia”. A video of this presentation can be watched here.

 

 

Link to original news item

Walter Immerzeel presents Himalayan research on the 10th anniversary of the ERC

Have you always wondered what these prestigious, multi-million euro research grants from the European Research Council (ERC) are all about? Are you interested how ERC research projects relate to your daily life? Together with nine other ERC laureates from Utrecht University, Walter Immerzeel presented his ERC research during the ERC Day ‘Utrecht Inspires’ on 28 March, which was part of celebrations of the 10th Anniversary of the ERC.

 

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