More than 70 international climate scientists met in Kathmandu earlier this month to begin the tricky scientific — and diplomatic — task of mapping glacial retreat in the world's highest mountains.

The massive glaciers of the Hindu Kush–Himalaya ranges supply some 1.3 billion people in the surrounding countries with water, and their retreat will have an impact on wetlands, agriculture and rangeland. Glacial lakes left by the melt are brimming, threatening to destroy homes and power stations (see Nature 438, 275–276; 2005). Yet there is little information about how the glaciers are changing as Earth warms. A comprehensive report released last year by the Intergovernmental Panel on Climate Change detailed the impact of global warming over much of the cryosphere — areas covered in snow, ice or permafrost — but the Himalayas were barely mentioned.

“This has been a blind spot, a big scientific question mark,” says geographer Mats Eriksson, programme manager for water and hazard management at the International Centre for Integrated Mountain Development (ICIMOD) based in Kathmandu, which helped organize the three-day workshop.

Increased monitoring is needed for Earth's highest glaciers. Credit: G. DIXON/LONELY PLANET/GETTY

The aim is to combine data from all over the region on atmospheric temperature, precipitation, wind speed, river discharge, topography and elevation to assemble models of water availability that might be useful for making policies on, for example, agriculture. There are too few remote-sensing stations, meaning that some models have been based on “very faulty information”, says Michael Bishop, a physical geographer at the University of Nebraska in Omaha, who helped organize the workshop. And different countries use different algorithms to process remote-sensing data. “We need protocols so the data can be prepared,” Bishop says.

The dearth of data makes it hard to assess danger and take measures to head off disaster. Studies outlining the impact of the retreating glaciers on people's lives, such as a 2005 report on glaciers in India, Nepal and China by the conservation group WWF, mostly depended on data five or ten years old, says WWF's Lifeng Li. ICIMOD, an independent centre funded by its eight member countries — Afghanistan, Bangladesh, Bhutan, China, India, Myanmar, Nepal and Pakistan — held the workshop to address these problems. It's been a long time coming, says Bishop, who spent four years trying to coordinate research activities among the region's scientists. Political friction always prevented members from attending.

Political sensitivities also make member countries hesitant to share data. Pakistan considers all aerial photos to be state secrets, and India is wary of sharing oceanographic and land-survey data. Both are reluctant to reveal locations of observatories, Bishop says. After more than two decades working in Pakistan with data from low-altitude climate stations, he was surprised to find out that the country also has high-altitude stations.

At the end of the workshop, the scientists called for each member state to have at least “one focal glacier under close long-term study, preferably including mass balance and velocity studies” and to “create basin-wide water scenarios for all major basins in the region”.

It is not yet clear to what extent the countries will increase investment in data collection. And the workshop's call to make data sharing “politically correct” will probably face resistance. But Bishop is hopeful: “For the first time I see Pakistanis and Indians really talking, really excited, and recognizing the scientific successes of the other country.”

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