The men­ace of gath­er­ing storms gain­ing mo­men­tum

China Daily (Canada) - - CHINA - By AN­DREA DENG in Hong Kong an­drea@chi­nadai­

Re­search data pub­lished by me­te­o­rol­o­gists and geog­ra­phers re­veal that the en­tire re­gion is not well pre­pared for the tor­ren­tial down­pours now ac­com­pa­ny­ing se­vere storms that have grown no­tably more fe­ro­cious in re­cent years un­der global warm­ing. People liv­ing in the re­gion are more likely to be caught off guard with the sud­den on­set of ex­treme weather.

Last year, the Swiss Rein­sur­ance Com­pany rated the Pearl River Delta (PRD) re­gion as the world’s third most vul­ner­a­ble ur­ban area to river floods, coastal storm surges and se­vere weather. Only the Tokyo-Yoko­hama met­ro­pol­i­tan area and Metro Manila are con­sid­ered more vul­ner­a­ble than the PRD.

Re­searchers ac­knowl­edged that the like­li­hood of a se­vere nat­u­ral dis­as­ter in this area may be re­mote, but that just one mas­sive storm could have cat­a­strophic re­sults, af­fect­ing one of China’s most im­por­tant commercial and man­u­fac­tur­ing cen­ters, an area that is home to more than 42 mil­lion people.

The po­ten­tial mag­ni­tude of any such catas­tro­phe here may be gauged from the dis­as­ter that struck the New Eng­land States, in­clud­ing New York City, in late Oc­to­ber 2012. Trop­i­cal storm Sandy, down­graded from a hur­ri­cane when it made land­fall, killed 117 people, 48 in New York City. Power to 7.9 mil­lion businesses and house­holds in 15 states was cut.

The tem­pest struck within two kilo­me­ters of Wall Street, forc­ing clo­sure of the New York Stock Ex­change for two con­sec­u­tive days for the first time since 1888. Dam­age in the states of New York and New Jersey, the hard­est hit ar­eas, came to nearly $80 bil­lion.

All coastal me­gac­i­ties in South­east Asia are ex­posed to cy­clones sim­i­lar to Sandy, the sec­ond most de­struc­tive trop­i­cal cy­clone on record, said Faith Chan Ka-shun, as­sis­tant pro­fes­sor at the Univer­sity of Not­ting­ham’s Ningbo cam­pus.

Me­te­o­rol­o­gists and geog­ra­phers have de­scribed Hong Kong as “lucky” so far. Most pow­er­ful cy­clones that have wrought heavy losses to lives and property in re­cent years have missed the city, some veer­ing off at the last minute to make land­fall in nearby re­gions.

Martin Wil­liams, a Hong Kong­based writer spe­cial­iz­ing in con­ser­va­tion and the en­vi­ron­ment, cited Typhoon Usagi in a re­cent ar­ti­cle. The storm that struck last Septem­ber forced Hong Kong to raise the No 8 storm sig­nal, but killed 35 people on the main­land.

Wil­liams pointed to su­per typhoon Haiyan, which struck the Philip­pines last Novem­ber, leav­ing 6,340 known dead and more than 1,000 miss­ing. Their bod­ies have never been found. He de­scribed it as sim­i­lar to the deadly typhoon that hit Hong Kong in 1906 — the un­named storm struck sud­denly, killing 15,000 people in the city.

An­other dread­ful storm surge hap­pened in 1937 in Hong Kong, tak­ing 11,000 lives.

Chan cited Typhoon Wanda in 1962, which gen­er­ated a se­vere storm surge, “at a one-in-50 re­turn pe­riod scale”, with a recorded mean sea level (MSL) of 5.34 me­ters that caused a 1.4-me­ter surge in Vic­to­ria Har­bour, caus­ing seawa­ter to over­flow the em­bank­ment and inun­dated North Point and She­ung Wan among other districts on Hong Kong Is­land. Wanda killed 130 people and de­stroyed 72,000 prop­er­ties, with eco­nomic losses es­ti­mated at HK$4.9 mil­lion.

Ex­perts high­lighted the flood­ing and storm his­tory in the re­gion not only be­cause such deadly ex­treme weather is likely to re­cur, but also that the in­ter­vals be­tween episodes of ex­treme weather are shorter. Floods can­not eas­ily be fore­cast, but it is well known and the risks are grow­ing.

New York City’s storm warn­ing sys­tem, for ex­am­ple, was ac­ti­vated less than 48 hours be­fore Sandy struck. Prepa­ra­tion time be­fore the on­set of a deadly storm is be­com­ing in­creas­ingly im­por­tant.

H Y Mok, a se­nior sci­en­tific of­fi­cer with the Hong Kong Ob­ser­va­tory (HKO), said that in the event of a se­ri­ous nat­u­ral dis­as­ter in Hong Kong, a large-scale evac­u­a­tion would be dif­fi­cult in densely pop­u­lated districts.

Lam Chiu-ying, ad­junct pro­fes­sor at the Depart­ment of Ge­og­ra­phy and Re­source Man­age­ment, the Chi­nese Univer­sity of Hong Kong, as well as for­mer HKO di­rec­tor, told China Daily that to ob­tain a clear as­sess­ment, one should ex­am­ine flood risks aris­ing from a storm surge, and his­tor­i­cal records show­ing that the mean sea level around Hong Kong is pro­gres­sively ris­ing. Equally im­por­tant is the in­creas­ing fre­quency of ex­treme weather, which many ex­perts be­lieve is linked to cli­mate change.

The UK’s Na­tional Weather Ser­vice says a storm surge arises from a com­bi­na­tion of low air pres­sure, high winds and fa­vor­able tidal con­di­tions that may lead to ex­ten­sive flood­ing in­land, pos­ing ex­treme dan­ger to people liv­ing in coastal ar­eas.

Hong Kong is hit by six ty­phoons ev­ery year on aver­age. The HKO keeps a data­base of the storm surge from ev­ery one of them. It’s been a long time since the city was hit by a se­vere storm surge, but as Chan noted, cli­mate change will lead to in­creas­ing peak wind in­ten­si­ties, and ris­ing fre­quency and in­ten­sity of storm surges.

The HKO and the Ma­cau Mar­itime Ad­min­is­tra­tion pre­dicted the rise of the sea level some years ago. They pre­dicted an an­nual rise of 3.9 mil­lime­ters in the PRD es­tu­ary. That would re­sult in a 20-cen­time­ter in­crease in the sea level by 2050. Last year, the HKO up­dated its projections and es­ti­mated that the sea level will rise by 40 cen­time­ters, on aver­age, by the mid­dle of the century.

There are other fac­tors, how­ever, that threaten to make ris­ing sea lev­els even more of a threat. In May, it was re­ported by NASA that six un­sta­ble and rapidly melt­ing glaciers in the Antarc­tica could re­lease enough wa­ter to raise the sea level by roughly 1.2 me­ters over the next 200 to 1,000 years. NASA re­searchers de­scribed the glaciers’ re­treat as hav­ing “reached the point of no re­turn”.

The sit­u­a­tion has aroused con­cern among me­te­o­rol­o­gists world­wide. They quickly pointed to the fact that ris­ing sea lev­els, un­der­pinned by in­creas­ingly ex­treme weather, raise the risk of flood­ing in­land. In Hong Kong, the con­se­quences of any such ma­jor event are dif­fi­cult to map out.

The HKO’s Mok told China Daily that be­cause Hong Kong has a com­plex coast­line and moun­tain­ous to­pog­ra­phy, it would be tech­ni­cally dif­fi­cult and costly to pre­pare an in­un­da­tion map that would al­low me­te­o­rol­o­gists to pre­dict storm surge po­ten­tial in the city and help with de­vel­op­ing con­tin­gency plans.

In­un­da­tion is com­mon in the PRD. Hong Kong boasts a bet­ter drainage sys­tem. Chan said the Drainage Ser­vices Depart­ment (DSD) “has done what it can” to sort out flood is­sues with en­gi­neer­ing ap­proaches. Nonethe­less, he warned that “the in­ten­sive rain­fall could still be too se­ri­ous to cope with, or some­times the block­age of storm sew­ers be­comes un­avoid­able, par­tic­u­larly in some highly ur­ban­ized districts”.

“As the ur­ban­iza­tion rate is pro­ceed­ing un­be­liev­ably fast, drainage ca­pac­i­ties and flood mea­sures may not be equally equipped to meet ad­e­quate stan­dards to pro­tect ur­ban, pop­u­lous ar­eas, which are the com­mon prob­lems in all PRD cities and most of the Chi­nese me­gac­i­ties, in my opin­ion,” Chan said. Ti­mothy Chui con­trib­uted to the ar­ti­cle.

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