Three years ago, a grim warning from the panel of scientists advising the United Nations on climate change caught the attention of policymakers in Asia.

In one of several long reports, the panel said that glaciers in the Himalayan mountain chain between India and China were “receding faster than in any other part of the world and, if the present rate continues, the likelihood of them disappearing by 2035 and perhaps sooner is very high if the Earth keeps warming at the current rate.”

Himalayan glaciers — slow-moving rivers of ice formed by compressed snow — cover about 3 million hectares or 17 percent of the mountain area. As the largest body of ice outside the polar caps, they store about 12,000 cubic km, releasing it through spring and summer meltwater into South Asia’s major rivers, on which hundreds of millions of people depend.

For countries plagued by chronic drought and widespread poverty, the prospect of the glaciers all but disappearing in barely a generation was alarming to say the least.

However, it turns out that this section of the report from the Intergovernmental Panel on Climate Change was from an unreliable source. As word of this spread widely recently it raised a storm of criticism, forcing the IPCC to admit that the passage had not been properly checked before publication.

Yet does this mistake in a 938-page report amount to a “glacier-gate” scandal and undermine the broad conclusion of the IPCC about global warming and glaciers in 2007? The panel said then that: “Widespread mass losses from glaciers and reductions in snow cover over recent decades are projected to accelerate throughout the 21st century, reducing water availability, hydropower potential, and changing seasonal flows in regions supplied by meltwater from major mountain ranges (e.g. Hindu-Kush, Himalaya, Andes), where more than one-sixth of the world population currently lives.”

The heads of the panel insist that this summary remains appropriate and entirely consistent with the underlying science. They are supported by the recent release of measurements from the World Glacier Monitoring Service (WGSM). These show that in glaciers surveyed the average mass balance continues to decrease, with preliminary figures indicating a further thickness reduction of 0.5 meters in 2007-08. This brings the cumulative average thickness loss of glacier ice reported since 1980 to about 12 meters.

The WGSM and the United Nations Environment Progam (UNEP) said in a 2008 report that ice loss over the previous 60 years exceeded 20 meters. They described this fall as “dramatic” when compared to the global average glacier thickness, which is estimated (by dividing volume by area) at somewhere between 100 meters and 180 meters.

Nonetheless, India’s environment minister Jairam Ramesh was so angry at the IPCC that he commissioned an investigation into the state of Himalayan glaciers. In the paper published in November, Vijay Raina, a leading Indian glaciologist, said that there was no sign of “abnormal” retreat in the mountain glaciers.

Intensifying research on glaciers worldwide is important because they are key barometers of global warming and climate change. Snow and ice will melt as average surface temperatures continue to rise. This is a basic physical principle.

However, the causes of changes in glacier thickness and length are much more complicated. This feeds into wider debate about the extent to which human activity, mainly fossil fuel burning and deforestation, are responsible for global warming and climate change.

Glaciers and ice caps, and the giant continental ice sheets of Antarctica and Greenland, cover some 10 percent of Earth’s land surface today. At the peak of the last ice age around 21,000 years ago, they extended over three times this area.

Scientific studies suggest that approximately 10,000 years ago (long before widespread fossil fuel burning and deforestation began with the industrial revolution of the past 200 years), pronounced warming reduced glaciers in most mountain ranges to extents comparable with conditions at the end of 20th century. What then caused this warming?

The WGMS has also noted that most of the glacier loss in the European Alps took place in the second half of the 19th century and the first half of 20th century, before the full brunt of carbon intensity was felt.

These are just two of many puzzles in glaciology. Partly because of the difficulties in measuring the behavior of glaciers — even with the recent aid of satellite sensors for remote coverage — under 100 of world’s estimated 160,000 glaciers are included in the WGMS glacier mass balance data, and only 30 of these glaciers in nine mountain ranges have been under continuous observation since 1980.

Most glacier knowledge relates to Europe, North America and New Zealand. There are big gaps in the polar regions and Asia, including India and China.

The governments of both these countries are intensifying their research efforts. India is setting up a glacier research center while the Chinese Academy of Sciences is expanding glacier studies on the Qinghai-Tibetan plateau, the source of major rivers flowing not only into China but also into South and Southeast Asia.

Without more complete knowledge of how glaciers behave and why, some of the key riddles of climate change will be difficult to solve.

Michael Richardson is a visiting senior research fellow at the Institute of South East Asian Studies in Singapore.

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