Michael Richardson, For The Straits Times 1 Feb 10;
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 the year 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 three million hectares or 17 per cent of the mountain area. The largest body of ice outside the polar caps - about 12,000 cubic kilometres - releases its store through spring and summer meltwater into South Asia's major rivers on which 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 (IPCC) was from an unreliable source. As word of this spread widely in the past few weeks, 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 undermine the broad conclusion of the IPCC in 2007?
According to the panel, '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 seasonality flows in regions supplied by meltwater from major mountain ranges... where more than one-sixth of the world's population currently lives'.
The panel insists that this summary remains appropriate and entirely consistent with the underlying science. The conclusion is supported by recent measurements of the World Glacier Monitoring Service (WGMS). These show that the average mass balance in the glaciers surveyed continues to decrease, with preliminary figures indicating a thickness reduction of 0.5m in 2007-08. This brings the cumulative average thickness loss since 1980 to about 12m.
The WGMS and the United Nations Environment Programme said in a 2008 report that the ice loss over the previous 60 years exceeded 20m. 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 100m and 180m.
India's environment minister Jairam Ramesh was so angry at the IPCC report that he commissioned an investigation into the state of Himalayan glaciers. In the paper published in November, Dr Vijay Raina, a leading Indian glaciologist, said there was no sign of 'abnormal' retreat in the mountain glaciers.
Research on glaciers worldwide is important because they are key barometers of global warming. 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 the wider debate about the extent to which human activity, mainly fossil fuel burning and deforestation, is responsible for global warming.
Glaciers and ice caps, including the giant continental ice sheets of Antarctica and Greenland, cover some 10 per cent of earth's land surface. 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), pronounced warming reduced glaciers in most mountain ranges to extents comparable with conditions at the end of the 20th century. What caused that warming?
The WGMS has also noted that most of the recent glacier loss in the European Alps took place in the second half of the 19th century and the first half of the 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 glacier behaviour - even with the aid of satellite sensors - less than 100 of world's estimated 160,000 glaciers are included in the WGMS glacier mass balance data, and only 30 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 knowledge of 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 centre 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 South-east Asia.
Without more knowledge of how glaciers behave, some of the key riddles of climate change will be difficult to solve.
The writer is a visiting senior research fellow at the Institute of Southeast Asian Studies.
