The
glaciers in the Karakoram Range between northern Pakistan and western China
have actually grown, rather than shrinking.
Unlike
most mountain glaciers, the Karakoram glaciers, which account for 3 percent of
the total ice-covered area in the world, excluding Greenland and Antarctica,
are not shrinking.
A
team of French glaciologists has recently confirmed that these glaciers on
average have remained stable or may have even grown slightly in recent years.
The
new study used data from satellites to study the Karakoram Range of northern
Pakistan and western China.
The
researchers found that the ice had actually increased in thickness by 0.11
(plus or minus 0.22) meters per year between 1999 and 2008.
Experts
cautioned that the gain is so small that the glaciers might not actually be
growing – but what is clear is that the glaciers are not shrinking, according
to a report published in Nature Geoscience.
Etienne
Berthier, a glaciologist at the Université de Toulouse in France says, ‘Not all
glacial regions are changing in the same way.
A
Nasa study earlier this year using the gravity-sensing GRACE satellites hinted
that ice loss in the high Asian mountains might be far less drastic than
earlier predictions.
Previous
estimates of ice loss in the high Asian mountains have ranged up to 50 billion
tons a year, according to the University of Colorado Boulder University’s
Professor John Wahr.
Previously,
it had been claimed by the UN that Himalayan glaciers would have melted to a
fifth of current levels by 2035, leading to sea level rises and drought.
Those
predictions used ground-based measurements; whereas the new study measured the
effect of gravity on twin Nasa satellites to give an accurate measure of the
mass of ice being lost.
‘The
results in this region really were a surprise,’ said Wahr.
‘One
possible explanation is that previous estimates were based on measurements
taken primarily from some of the lower, more accessible glaciers in Asia and
were extrapolated to infer the behavior of higher glaciers.’
‘But
unlike the lower glaciers, many of the high glaciers would still be too cold to
lose mass, even in the presence of atmospheric warming.’
Around
the world, melting has been overestimated. Earth’s glaciers and ice caps are
shedding roughly 150 billion tons of ice annually – up to 30 per cent lower
than predicted.
The
researchers used satellite measurements taken with the Gravity Recovery and
Climate Experiment, or GRACE,, to calculate that the world’s glaciers and ice
caps had lost about 148 billion tons, or about 39 cubic miles of ice annually
from 2003 to 2010.
Traditional
estimates of Earth’s ice caps and glaciers have been made using ground-based
measurements from relatively few glaciers to infer what all of the unmonitored
glaciers around the world were doing, he said.
Only
a few hundred of the roughly 200,000 glaciers worldwide have been monitored for
a decade or more.
‘The
strength of GRACE is that it sees everything in the system,’ said Wahr. ‘Even
though we don’t have the resolution to look at individual glaciers, GRACE has
proven to be an exceptional tool.’
The
total does not count the mass from individual glacier and ice caps on the
fringes of the Greenland and Antarctic ice sheets — roughly an additional 80
billion tons.
Pakistan Cyber Force
No comments:
Post a Comment