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Climate change

发布时间:2015/10/5 7:54:17  点击次数:385 次

Climate change

THREAT OF GLACIAL LAKE OUTBURSTS

LAL DEOSA RAI

Three lakes, Imja,Thulagi and Tsho Rolpa, have been studied and investigated and more detailed investigations of potentially dangerous glacial lakes are called for. Ultimately, climate warming will continue inevitably, and so also the accelerated glacier thinning and retreat

outbursts of glacier

It is no longer a point of debate that human activities have extensively contributed to the current acceleration of climate change — traditionally  nature’s act. With the  onset of global warming in about the second half of the 19th century, many glaciers throughout the world, including in the Great Himalayan range, began to thin resulting in formation of glacier lakes at the termini ends of glaciers– that is to say, perennial bodies of ice and snow deformed  and shifted to lower level, under its own weight. A wish — had there been a lesser degree of industrialization coupled with even lesser intense urbanization, the issue of greenhouse effect would not have become an acute cause for contemporary  international climate change  concern!

For the countries lying under the shadow of the great Himalayas the threat of glacial lake outburst floods have assumed a dangerous proportion beyond imagination. One of the reasons is that the end moraine (a loose mix of rock debris) of these lakes  makes them potentially unstable as the volume of lake water increases the moraine dam is stressed  which eventually may give way to hydrostatic pressure and release much or all of the lake water. The resultant surging flood water can be sudden and disastrous to people and settlements along the flooded river.  In the history  of the world, some catastrophic glacial lake outbursts floods (GLOF) have caused extensive damage and loss of  life  further downstream.

According to ICIMOD there are 8790 glacial lakes along the selected location of the Hindu Kush-Himalayas of which 204 are liable to burst out at any moment leading to massive floods downstream. ICIMOD adds that at least 35 glacial lake outburst floods have already happened in Bhutan, China and Nepal during the 20th century.

For a country like Nepal, this threat was unknown half a century ago, except for one GLOF that occurred along the Seti River about 450 years ago  when the 50-metre deep  debris   had mantled the Pokhara valley. Now, according to a recent  ICIMOD  remote sensing study, in this country alone more than 1400 glacier lakes have come up  owing to the melting  of the  Himalayan ice under the impact climate warming; of these six are vulnerable to outburst  with the potential to cause havoc  in the downstream human settlements.  Three lakes, Imja,Thulagi and Tsho Rolpa, have been studied and investigated  and more detailed investigations of potentially dangerous glacial lakes are called for.  Ultimately, climate warming will continue inevitably, and so also the accelerated glacier thinning and retreat.  Many Nepali villages and bazaars along the snow-fed  river basins have become extremely vulnerable to the threat of glacier lake outburst floods.

Moreover, since the Hindu Kush-Himalayan range is admittedly one of extreme seismic instability, the earthquake hazards make glacial lake outburst flood assessment  all the more issues of  extreme urgency, particularly for Nepal.

The public concern for the issues of glacial lake outburst flood risk assessments, early warning systems, and adaptation measures to reduce climate change impact are becoming ever more urgent. No doubt, in policy  formulation Nepal has been aware of it since the 1980s when the sixth Five Year Plan recognized the relevance of environmental development problem. In the same decade the SAARC leaders also expressed  their concerns  for adverse impacts of climate change and set agendas to address the multiple climate change problems.

Nepal has been participating in all climate change international conferences to assert its views and inform the international community about its efforts to adapt to the climate change effects, despite international intrigues.

Since then the issue of adaptation to climate effects has occupied the thinking of development planners and decision-makers in Nepal. And this year the quake of 7,8 Richter scale has  shaken  them to rise to the urgency of protecting  the environment as a part of the State‘s human obligations. This is not to say the Nepal Government has  been negligent of its  obligations for reducing the impact of glacier lake outburst floods. The only lag has been between strategic  planning and its process of operation  from year to year.   The recent  temblors may have deterred the government from implementing its early warning systems.

Now that  the quake threat is in its  waning phase there is no alternative  to urgent  national action  in securing safety of life and properties  along  the GLOF threatened river  settlements. However, it is disconcerting to note that a very recent news report said the Chho-Rolpa warning sirens set up in rural areas of Ramechhap and Dolakha have been lying defunct due to government negligence.

This is not the way to adapt technologically in order to meet climate changes issues that relate to human beings surviving in conditions of poverty  and inequality. Because, as Bill Gates has succinctly put it recently, “Just one stroke of bad fortune – a drought , a flood. or illness  — is enough for the world’s poorest farmers to tumble deeper into poverty and hunger”.


A version of this article appears in print on October 05, 2015 of The Himalayan Times.

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