Featured Research

from universities, journals, and other organizations

State of Himalayan glaciers less alarming than feared

Date:
April 19, 2012
Source:
University of Zurich
Summary:
Several hundreds of millions of people in Southeast Asia depend, to varying degrees, on the freshwater reservoirs of the Himalayan glaciers. Consequently, it is important to detect the potential impact of climate changes on the Himalayan glaciers at an early stage. Glaciologists now reveal that the glaciers in the Himalayas are declining less rapidly than was previously thought. However, the scientists see major hazard potential from outbursts of glacial lakes.

This is an aerial view of the Imja glacier and Lake Imja, Nepal, the Himalayas. The lake appeared in the 1960s and has grown continuously ever since. The sinking of the surface of the debris-covered glacier tongue is also clearly discernible.
Credit: J. Kargel, University of Arizona

Several hundreds of millions of people in Southeast Asia depend, to varying degrees, on the freshwater reservoirs of the Himalayan glaciers. Consequently, it is important to detect the potential impact of climate changes on the Himalayan glaciers at an early stage. Together with international researchers, glaciologists from the University of Zurich now reveal that the glaciers in the Himalayas are declining less rapidly than was previously thought. However, the scientists see major hazard potential from outbursts of glacial lakes.

Ever since the false prognoses of the Intergovernmental Panel on Climate Change (IPCC), the Himalayan glaciers have been a focus of public and scientific debate. The gaps in our knowledge of glaciers in the Himalayan region have hindered accurate statements and prognoses. An international team of researchers headed by glaciologists from the University of Zurich and with the involvement of scientists from Geneva now outlines the current state of knowledge of glaciers in the Himalayas in a study published in Science. The scientists confirm that the shrinkage scenarios for Himalayan glaciers published in the last IPCC report were exaggerated.

Glacier area 20 percent smaller than assumed

The most up-to-date mappings so far based on satellite data revealed that glaciers in the Himalayas and Karakoram cover a total area of approximately 40,800 km². While this is around twenty times larger than all glaciers of the European Alps put together, it is as much as twenty percent smaller than was previously assumed. Lead scientist Tobias Bolch, who researches at the University of Zurich and Dresden University of Technology, mainly puts this down to erroneous mappings in earlier studies.

Less shrinkage than predicted

The scientists took all the existing measurements of length, area and volume changes and mass budgets into account for their study. While some of the measurement series on length changes date back to 1840, measurements of glacier mass budget that instantaneously reflect the climate signal are rare. In addition, continuous measurement series do not stretch back any further than ten years. The researchers recorded average length decreases of 15 to 20 metres and area decreases of 0.1 to 0.6 percent per year in recent decades. Furthermore, the glacier surfaces lowered by around 40 centimetres a year. "The detected length changes and area and volume losses correspond to the global average," explains Bolch, summarizing the new results. "The majority of the Himalayan glaciers are shrinking, but much less rapidly than predicted earlier."

For the regions in the northwestern Himalayas and especially in the Karakoram Range, the researchers noted very heterogeneous behaviour in the glaciers. Many of them are dynamically unstable and prone to rapid advances (so called "surges") that largely occur independently of the climatic conditions. For the last decade on average, even a slight volume increase was detected. Based on their analyses, the researchers assume that glacier shrinkage will not have a major impact on the water drainage of large rivers like the Indus, Ganges and Brahmaputra in the coming decades.

Greater variability and menacing flooding of glacial lakes

Despite the partial all-clear for the Himalayan glaciers, however, Bolch advises caution: "Due to the expected shrinkage of the glaciers, in the medium term we can expect a greater variability in the seasonal water drainage. Individual valleys could dry up seasonally."

Bolch and his colleagues also see a very serious threat to the local population in newly formed or rapidly growing glacial lakes. The deluge of water and debris from potential outbursts of these lakes could have devastating consequences for low-lying regions. According to the scientists, increased efforts are urgently needed to monitor the lakes as well as changes in the glaciers and the climate in the Himalayas.

The study was conducted as part of the EU project High Noon and the European Space Agency project Glaciers_cci.


Story Source:

The above story is based on materials provided by University of Zurich. Note: Materials may be edited for content and length.


Journal Reference:

  1. T. Bolch, A. Kulkarni, A. Kaab, C. Huggel, F. Paul, J. G. Cogley, H. Frey, J. S. Kargel, K. Fujita, M. Scheel, S. Bajracharya, M. Stoffel. The State and Fate of Himalayan Glaciers. Science, 2012; 336 (6079): 310 DOI: 10.1126/science.1215828

Cite This Page:

University of Zurich. "State of Himalayan glaciers less alarming than feared." ScienceDaily. ScienceDaily, 19 April 2012. <www.sciencedaily.com/releases/2012/04/120419143119.htm>.
University of Zurich. (2012, April 19). State of Himalayan glaciers less alarming than feared. ScienceDaily. Retrieved August 29, 2014 from www.sciencedaily.com/releases/2012/04/120419143119.htm
University of Zurich. "State of Himalayan glaciers less alarming than feared." ScienceDaily. www.sciencedaily.com/releases/2012/04/120419143119.htm (accessed August 29, 2014).

Share This




More Earth & Climate News

Friday, August 29, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Killer Amoeba Found in Louisiana Water System

Killer Amoeba Found in Louisiana Water System

AP (Aug. 28, 2014) — State health officials say testing has confirmed the presence of a killer amoeba in a water system serving three St. John the Baptist Parish towns. (Aug. 28) Video provided by AP
Powered by NewsLook.com
Scientists Have Figured Out Why Rocks Move In Death Valley

Scientists Have Figured Out Why Rocks Move In Death Valley

Newsy (Aug. 28, 2014) — The mystery of the moving rocks in Death Valley, California, has finally been solved. Scientists are pointing to a combo of water, ice and wind. Video provided by Newsy
Powered by NewsLook.com
Big Waves, Minor Flooding from Hurricane

Big Waves, Minor Flooding from Hurricane

AP (Aug. 27, 2014) — Thundering surf spawned by Hurricane Marie pounded the Southern California coast Wednesday, causing minor flooding in a low-lying beach town. High surf warnings were posted for Los Angeles County south through Orange County. (Aug. 27) Video provided by AP
Powered by NewsLook.com
Calif. Quake Underscores Need for Early Warning

Calif. Quake Underscores Need for Early Warning

AP (Aug. 26, 2014) — Researchers at UC Berkeley are testing a prototype of an earthquake early warning system that California is pursuing years after places like Mexico and Japan already have them up and running. (August 26) Video provided by AP
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins