State of Himalayan glaciers less alarming than feared

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.

Literature:

T. Bolch, A. Kulkarni, A. Kääb, 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. 20 April, 2012. doi: 10.1126/science.1215828.


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3 thoughts on “State of Himalayan glaciers less alarming than feared”

  1. Hi

    I was reading a 2008 article of BBC News about Alps melting here:

    http://news.bbc.co.uk/2/hi/science/nature/7580294.stm

    They write :

    “What fascinates scientists about the age of the finds is that they correspond to times when climate specialists have already calculated the Earth was going through an especially warm period, caused by fluctuations in the orbital pattern of the Earth in relation to the Sun.”

    Ok…seems right. After all there is the main effect of solar radiations on Earth’s climatic changes .And as the article says many years ago, (much before the CO2 mania) there was men living in areas where there was no glaciers. The same areas had cycles of warming and cooling , More and less areas of ice. Seems logical.

    However the conclusion of the article is a complete joke:

    “But what we do know is that the climate has fluctuated throughout history; in the past the driving force for the changes was the Earth’s orbital pattern, NOW the driving force is green house gas emissions.”

    Thats very funny : Only after 5000 years the driving force of the orbital pattern of the Earth purely disapeared !!!!!
    Maybe those climate specialists are also fascinated by the temporary random and ocasional Earth’s orbit ! lol

    At least they could have been more coherent. If in the end they wanted no matter how to blame gas emissions they could have calculated the “Earth especially warm period” also because of another important green house gas emission : The now well known flatulence of Mammoth´s wich alike the article itself, also smells to bullshit…

    Francisco, Lisbon, Portugal

    Reply
  2. There’s a whole lot wrong with this article.

    Just one for starters. The first statement.


    Several hundreds of millions of people in Southeast Asia depend, to varying degrees, on the freshwater reservoirs of the Himalayan glaciers.

    Here’s a picture so you can see

    http://rajeev-dubey.blogspot.co.uk/2011/05/trek-to-milam-glacier-himalayas-india.html

    Next to the output stream of a glacier, in summer when the temperature is high and the outflow of melt water high.

    Hmm, several hundreds of millions of people rely on a few streams like that for all their water.

    Yes – right.

    Here’s a nice picture of a river that those people do rely on

    http://www.vagabondjourney.com/2010-1/10-4619-sunrise-ganges-river-varanasi.jpg

    It’s large.

    Now even combining the outflow from lots of glaciers, it doesn’t come to more than a spit ball in the context of the river flow.

    So where does the water come from?

    http://newsimg.bbc.co.uk/media/images/41966000/jpg/_41966554_india_ap416.jpg

    It’s from the Monsoon. It’s rain. It’s not melt water from glaciers.

    If the first sentence is complete codswallop, the rest of the article is suspect.

    Reply
    • I dunno. The editors at Science seemed to think it made sense:

      T. Bolch, A. Kulkarni, A. Kääb, 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. 20 April, 2012. doi: 10.1126/science.1215828.

      Reply

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