Helen Scales

Climate Change Threatens the Roof of the World

Scientists 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.

- January 2005

About the Author

Helen is a marine biologist at the University of Cambridge