Bedmap Himalayas

Bedmap Himalayas

Start date
1 March, 2014

Bedmap Himalayas is an ongoing BAS core-funded and grant-funded programme that aims to measure how much water much is stored as glacier ice in High Mountain Asia. In warm weather, water from melting glaciers sustains the flow of rivers through dry seasons or droughts, providing fresh water after the rains have stopped and seasonal snow has disappeared. This sustaining water reserve ensures that crops can be irrigated rather than failing, hydropower turbines keep turning, and downstream life can continue even in the hottest and driest foothills and plains.

High Mountain Asia has the greatest mountain glaciers outside Alaska and a very large population of 800 million people living downstream depend to some extent on their meltwater. In the Indus catchment for example, 237 million people are heavily dependent on glacier runoff for irrigation in the dry season, a population growing by 4 million per year. A quarter of Bhutan’s national income comes from hydropower on glacier-fed rivers.

Bedmap Himalayas is about answering the question: what will happen to Asia’s water supply in future?

From 2003-2009, this region lost 26 ± 12 billion tonnes of ice per year (which is like removing 12 River Thames each year), so how long will the ice last? We need to know the volume of stored ice before we can answer that, but this is remarkably poorly known due to an almost complete lack of glacier thickness measurements.

We commonly measure glacier thickness in Antarctica using radar waves that pass through ice and reflect from the rock below. Mountain glaciers are more challenging because they are dirtier and wetter so the first step was to test the radar in these conditions. In spring 2015, I carried out a pilot study (called ‘Bedmap Himalayas – Reconnaissance’) on glaciers in the Langtang Valley of Nepal to find out which radar frequencies will see through to the bed and reveal glacier thickness. The success of this pilot study means that our engineers are now working on designing a helicopter-mounted version of the radar that will make it very much easier to survey over the large areas and extremely rugged mountain terrain.

The next step is to build this airborne system and to test it out in the field and to do this, I am applying for funds to work with Indian scientists to construct and deploy our survey radar in Himachal Pradesh, on glaciers that supply the north Indian plains and the great Indus River with meltwater, a project called ‘Bedmap India – air survey of Himachal glaciers’.

Alongside this, I am working with the Cambridge Judge Business School to assess the importance of High Mountain Asia’s glaciers in the regional hydro-economy, using regional climate statistics and inventories of glaciers and dams to quantify just what role they play and what would happen if the glaciers where not there, and BAS-Cambridge PhD student Mike McCarthy is focussing on the role of glacier debris cover on ice melt rates. These elements will come together in studies that employ models of glacier mass balance, river basin hydrology and climate to make predictions of future water availability for the huge and growing populations downstream. Towards this goal, I am also collaborating on a proposal to the UK’s large-scale interdisciplinary collaboration with India, the Newton-Bhabha programme on Sustaining Water Resources for Food, Energy & Ecosystem Services in India.


himalaya1 himalaya2

  • to develop an ice-sounding radar system for mountain glaciers
  • to measure glacier ice volume on the river-catchment scale in High Mountain Asia
  • to help predict the future of Asia’s water supplies

Michael McCarthy

BAS Honorary Researcher

Measuring glaciers in the Himalayan mountains

11 October, 2018

Technology pioneered in Antarctica could soon be providing much-needed data on the amount of ice in the glaciers of High Mountain Asia thanks to an ingenious helicopter-mounted, low-frequency radar developed …