Melt­ing moun­tains

Fears rise over mas­sive flood­ing in the Hi­malayas as glaciers melt due to cli­mate change.

The Star Malaysia - Star2 - - ECOWATCH - By Suzanne Gold­en­berg

It’s strangely calm­ing to watch the Imja glacier lake grow, as chunks of ice part from black cliffs and fall into the grey­green lake be­low.

But the lake is a high-al­ti­tude dis­as­ter in the mak­ing – one of dozens of new dan­ger zones emerg­ing across the Hi­malayas be­cause of glacier melt caused by cli­mate change. If the lake, sit­u­ated at 5,100m in Nepal’s Ever­est re­gion, breaks through its walls of glacial de­bris, known as mo­raine, it could re­lease a del­uge of water, mud and rock as far as 100km. this would swamp homes and fields with a layer of rub­ble up to 15m thick, lead­ing to the loss of the land for a gen­er­a­tion. But the ques­tion is when, rather than if.

Moun­tain re­gions from the An­des to the Hi­malayas are warm­ing faster than the global av­er­age un­der cli­mate change. Ice turns to water; glaciers are slowly re­duced to lakes.

When sir Ed­mund Hil­lary made his suc­cess­ful ex­pe­di­tion to the top of Ever­est in 1953, Imja did not ex­ist. But it is now the fastest-grow­ing of some 1,600 glacier lakes in Nepal, stretch­ing down from the glacier for 2.5km and spawn­ing three small ponds. At its cen­tre, the lake is about 600m wide, and ac­cord­ing to govern­ment stud­ies, up to 96.5m deep in some places. It is grow­ing by 47m a year, nearly three times as fast as other glacier lakes in Nepal.

“the ex­pan­sion of Imja lake is not a ca­sual one,” said Pravin Raj Maskey, a hy­drol­o­gist with Nepal’s min­istry of ir­ri­ga­tion.

the ex­tent of re­cent changes to Imja has taken glacier ex­perts by sur­prise, in­clud­ing teiji Watan­abe, a ge­og­ra­pher at Hokkaido Univer­sity in Ja­pan, who has car­ried out field re­search at the lake since the 1990s. Watan­abe re­turned to Imja in septem­ber, mak­ing the nine-day trek with 30 other sci­en­tists and en­gi­neers on a United states-funded ex­pe­di­tion led by the Moun­tain In­sti­tute. He said he did not ex­pect such rapid changes to the mo­raine, which is hold­ing back the lake.

“We need ac­tion, and hope­fully within five years,” Watan­abe said. “I feel our time is shorter than what I thought be­fore. ten years might be too late.”

Un­like or­di­nary flash floods, a glacier lake out­burst is a con­tin­u­ing catas­tro­phe.

“It’s not just the one-time dev­as­tat­ing ef­fect,” said sharad Joshi, a glaciol­o­gist at Kath­mandu’s trib­hu­van Univer­sity, who has worked on Imja. “Each year, for the com­ing years it trig­gers land­slides and re­minds vil­lagers that there could be a dev­as­tat­ing im­pact that year, or ev­ery year. some of the ti­betan lakes that have had out­burst floods have flooded more than three times.”

But mo­bil­is­ing en­gi­neer­ing equip­ment and ex­per­tise to a lake 5,100m up and sev­eral days’ hard walk­ing away from the near­est trans­port hub is chal­leng­ing in Nepal, one of the poor­est coun­tries in the world. Peo­ple liv­ing in the small vil­lage of Ding­boche be­low the lake say sci­en­tists and govern­ment of­fi­cials have been talk­ing about the dan­gers of Imja for years.

some years ago, one of the vis­it­ing ex­perts was so con­vinc­ing about the dan­gers of an im­mi­nent flood that the vil­lagers packed up all their an­i­mals and valu­ables and moved to the next val­ley. they came back af­ter a week when the dis­as­ter did not ma­te­ri­alise, but say it’s hard to dis­miss the idea that there could be a flood one day.

“When I was 21, I went to the lake and it was black and re­ally small,” said Ang­n­ima sherpa, who heads a lo­cal con­ser­va­tion group in Ding­boche. “two years ago I went there and it was re­ally big. I couldn’t be­lieve it could get so big. It was re­ally scary.”

But sci­en­tists and en­gi­neers still can­not agree on whether to rate Imja as the most dan­ger­ous glacier lake in the Hi­malayas, or a more dis­tant threat. Mo­bil­is­ing in­ter­na­tional as­sis­tance for large-scale en­gi­neer­ing projects dur­ing a global re­ces­sion is also dif­fi­cult. the Moun­tain In­sti­tute’s ini­tia­tive was to call in ex­perts from the An­des, where Peru­vians have de­vel­oped sys­tems for con­tain­ing glacier floods since a dis­as­ter in the 1940s killed nearly 10,000 peo­ple.

Ce­sar Por­to­car­rero, who heads the depart­ment of glaciol­ogy at Peru’s national water agency, has over­seen en­gi­neer­ing works to drain more than 30 glacier lakes, build­ing tun­nels or chan­nels to drain the water and re­duce the risk of flood­ing. But he con­ceded it would be an enor­mous chal­lenge to ap­ply these meth­ods at Imja.

“It’s not easy to say ‘we are go­ing to siphon the water out of the lake’,” Por­to­car­rero said. “Where do you find the peo­ple who can work at high al­ti­tudes? How do you move in the equip­ment? What do you do in bad weather? You have to have ex­haus­tive plan­ning.”

there are also other con­tenders for im­me­di­ate ac­tion, with some 20,000 glacier lakes across the Hi­malayas, although many are con­cen­trated in the Ever­est re­gion. Bhutan alone has nearly 2,700. three of those, known as the Lu­nana com­plex, are prac­ti­cally touch­ing, in­creas­ing the pos­si­bil­ity of cas­cad­ing floods far more dev­as­tat­ing than any rup­ture at Imja.

“If the bar­rier fails be­tween them we are go­ing to have a mas­sive glacier lake out­burst flood,” said sonam Lhamo, a ge­ol­o­gist for the Bhutanese govern­ment.

the United Na­tions De­vel­op­ment Pro­gramme and other agen­cies have sup­ported a project to drain the lakes but those

funds are run­ning out.

John Reynolds, a Bri­tish en­gi­neer and ex­pert on glacier lakes who has worked in Nepal, ar­gues that the in­ter­na­tional com­mu­nity has fo­cused on Imja be­cause of its prox­im­ity to Ever­est and trekking routes pop­u­lar with western tourists. He says there are other, more haz­ardous lakes else­where.

The Nepali govern­ment ranks Imja among the six most dan­ger­ous glacier lakes in the coun­try largely be­cause it is grow­ing so quickly. More than 12 other such lakes are also seen as high risk.

But Reynolds ar­gued: “Just be­cause a lake is get­ting big­ger doesn’t nec­es­sar­ily mean that it is get­ting more haz­ardous. As the cli­mate is chang­ing, gen­er­ally speak­ing, more glacial lake sys­tems are form­ing.

“The ques­tion is how to de­cide which ones are haz­ardous now and which ones have the propen­sity to be­come haz­ardous in the fu­ture.”

Imja, though fast-grow­ing, is held in by a rel­a­tively wide mo­raine, which makes it se­cure in com­par­i­son to some oth­ers.

Most glacial lake floods be­gin as high­alti­tude tsunamis. A large block of ice fall­ing from a glacier at great height sets off a se­ries of gi­ant waves that wash over the mo­raine. That’s not such a risk for Imja. The glaciers feed­ing the lake are grad­ual in slope, which re­duces the risk of a large chunk of ice fall­ing from a great height and set­ting off large waves.

Watan­abe con­cedes the ge­og­ra­phy of the lake could keep dis­as­ter at bay, at least in the next year or two. But, he says, there are signs that an out­let chan­nel at the bot­tom of the lake may be widen­ing dan­ger­ously.

Reynolds said Nepal and the in­ter­na­tional com­mu­nity need to think of a Hi­malaya-wide ac­tion plan.

“As the cli­mate is chang­ing more glacial lake sys­tems are form­ing,” he said. “The ques­tion is how to de­cide which are haz­ardous now and which are go­ing to be­come haz­ardous in the fu­ture.” – Guardian News & Me­dia 2011

Ice flow:

a Nepalese porter walk­ing with his load near Go­rak Shep as the Khumbu glacier is seen in the back­ground in Nepal. Hi­malayan glaciers are thaw­ing at an alarm­ing rate with the hike in global tem­per­a­tures.

a moun­taineer over­look­ing the Imja glacier lake in the ever­est re­gion of Nepal. The lake did not ex­ist 50 years ago but started to form be­cause of ice melt caused by global warm­ing.

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