Science Articles

Climate Change Threatens the Roof of the World

Wed, 5th Jan 2005

Helen Scales

MountainScientists from the United Nations Environment Programme (UNEP) and International Centre for Integrated Mountain Development (ICIMOD) have studied topographical maps, aerial photographs and satellite images since 1999. They have revealed that at least 44 glacial lakes in Nepal and Bhutan are growing in size so rapidly that they could burst their banks within as little as five years' time. Research is showing that glaciers are melting more and more rapidly and consequently the lakes that are fed by glaciers are growing in size. Combined with this is an associated increase in air temperature. Long-term monitoring in Nepal has shown an average air temperature increase of 1°C since the 1970's. The Tsho Rolpa Lake in Nepal is now six times bigger than it was in the late 1950's. Ten thousand human lives, thousands of livestock, areas of agricultural land and many bridges are at high risk from this lake flooding. An early warning system is being installed to link the lake to villages at risk from floodwaters. Sensors and sirens will hopefully be effective at warning people against an impending flood, but this will not save infrastructure or agricultural land. Engineering work is also underway to try to lower the water levels of the Tsho Rolpa Lake by 30 metres. Systems of siphons are used to drain away water in a controlled way, and there are plans for the potential development of hydroelectric schemes powered by this excess water. To put this into perspective, Glacial Lake Outburst Floods (GLOFs) are not a new phenomenon; they have simply been happening more frequently over the last 30 years. But the damage they can cause is huge. In 1985 a sudden flood from the Dig Tsho Lake in Nepal destroyed 14 bridges and led to US$1.5 million worth of damage to a small hydropower plant. Surendra Shrestha, Regional Coordinator in Asia for UNEP's Division of Early Warning and Assessment, warns that solving the problem of GLOFs, "is going to be costly because glacial lakes are situated in remote areas which are difficult to reach". Much more money is urgently needed to carry out similar work in other areas that may be at risk from these potentially devastating floods. A UNEP spokesperson told edie that this problem is likely to be globally widespread, including areas in South America and China. Other regions of the Himalayas could not be included in this study due to the sensitivity of working on the ground, for example in areas of Pakistan and India where there are border disputes. Coupled with this, current resources are just not enough to carry out surveys and install early warning systems in all the areas where glacial flooding is likely to be a threat. The spokesperson pointed out that, "The areas studied in Nepal and Bhutan have mainly small human settlements with relatively small populations. However in other potentially dangerous regions, for example in India and China, there are far larger human populations that could be at risk from glacial lake flooding." Rapid melting of glaciers and snowfields may also lead to disruption of water supplies, fisheries and other wildlife. Klaus Töepfer, the Executive Director of UNEP warns that, "If the glaciers continue to retreat at the rates being seen in places like the Himalayas, then many rivers and freshwater systems could run dry." This news also arrives during the UN International Year of Mountains. The aim of this year is to promote the conservation and sustainable development of mountain regions and raise public awareness of their global importance. In October 2002 the Bishkek Global Mountain Summit, held in the Republic of Kyrgystan, agreed on concrete actions for the sustainable development and management of mountain areas. The impact of global climate change on natural systems and human populations was also an issue placed under the microscope at the World Summit on Sustainable Development held in Johannesburg last summer.

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