A large glacial lake formed due to melting of the Imja Tso glacier in the Himalayas
Naysayers notwithstanding, new studies show that Himalayan glaciers are indeed melting possibly due to climate change.
The
rate of their melting is not as alarming as projected by the
Intergovernmental Panel on Climate Change (IPCC) in 2007 but is
significant enough to seriously impact water availability in Asia in
future.
The warning
comes from a new study which has found that glaciers in the Himalayas
and Karakoram occupy an area of 40,800 square kilometers. The new
estimate is almost 20 percent lower compared to earlier projections.
Based on data relating to length,
area, volume changes and mass budgets, the study shows that 0.4 per cent
of glacier area is getting depleted every year.
The
study, published in journal Science this week, puts at rest controversy
generated due to projections about melting of Himalayan glaciers by
2035 as well as Indian studies that showed slower or zero rate of
retreat of glaciers.
Now,
scientists say that measuring horizontal retreat of glaciers could be
misleading criterion of assessing health of a glacier. Many Indian
glaciers are not retreating at terminus because of accumulation of
debris but higher reaches of the very same glaciers may be melting.
That's why measuring overall ice mass
is a better indicator of melting, scientists said. An average length
decrease of 15 to 20 metres and area decrease of 0.1 to 0.6 per cent per
year have been recorded in recent decades. Glacier surfaces have
lowered by around 40 centimetres a year.
Glaciers in the Indian Himalayas are losing one metre of ice every year compared to 0.4 metre earlier.
'The
loss in mass of glaciers in Indian Himalayas has significantly gone up
1998 onwards.
Such loss is more sensitive to climate change than
horizontal retreat,' Dr Anil Vishnu Kulkarni of Indian Institute of
Science, one of the co-authors of the study explained.
Dr
Kulkarni said initial studies have shown that black carbon - resulting
from forest fires and burning of agricultural waste is one of the main
contributors towards melting.
Transport
of black carbon from lower reaches to mountain tops needs to be
monitored regularly. Tobias Bolch of University of Zurich, who led the
study, said 'majority of the Himalayan glaciers are shrinking, but much
less rapidly than predicted earlier. But even a slow disappearance of
glaciers could have serious consequences on water availability in Asia'.
In the medium term,
greater variability in the seasonal water drainage is likely. Newly
formed or rapidly growing glacial lakes also pose a threat to local
populations
I'd like to refer the reader to these other articles previously publised:
State of Himalayan Glaciers Less Alarming Than Feared
State of Himalayan Glaciers Less Alarming Than Feared
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