Cy­clones less, worse

Port Douglas & Mossman Gazette - - NEWS - RICHARD KOSER

CLI­MATE change may ac­tu­ally re­sult in fewer, but big­ger, cy­clones hit­ting the North Queens­land coast over the next cen­tury.

A cli­mate change con­fer­ence in Cairns last week heard the lat­est re­sults from Aus­tralia’s lead­ing cli­mate sci­en­tists.

Two dif­fer­ent groups re­ported on the lat­est com­puter mod­el­ling of cy­clone fre­quency lead­ing out to 2100.

CSIRO re­searcher Deb­bie Abbs said her re­search in­di­cated ris­ing tem­per­a­tures could halve the num­ber of trop­i­cal cy­clones by the end of the cen­tury.

“On av­er­age for the pe­riod 2051-2090 rel­a­tive to 1971-2000, the sim­u­la­tions show an ap­prox­i­mately 50 per cent de­crease in the oc­cur­rence (of cy­clones) for the trop­i­cal re­gion,” Dr Abbs said.

Dr Abbs said her com­puter mod­els in­di­cated trop­i­cal cy­clones won’t last quite as long, and they will, on av­er­age, move about 100km fur­ther south.

How­ever, she ex­pects trop­i­cal cy­clones will be more in­tense.

“There’s a greater risk they will oc­cur in the more ex­treme cat­e­gory,” Dr Abbs said.

Univer­sity of Mel­bourne As­so­ciate Pro­fes­sor Kevin Walsh, who is car­ry­ing out in­de­pen­dent re­search into the same is­sue, said his pre­lim­i­nary con­clu­sions were along the same lines as Dr Abbs’.

Pro­fes­sor Walsh said his re­search in­di­cated cy­clones would be­come 20 per cent less com­mon by 2100, but that their max­i­mum in­ten­sity would in­crease by 5 per cent.

“The most in­tense (cy­clones) will be slightly more in­tense,” he told the con­fer­ence.

The re­search con­firmed a trend iden­ti­fied over­seas and now ac­cepted as the cli­mate or­tho­doxy.

How­ever, the con­fer­ence was told other is­sues of concern to lo­cals, such as fu­ture rain­fall pat­terns, were clear.

“Many lines of ev­i­dence over many years have pointed to de­creases in rain in south­ern Aus­tralia,” se­nior CSIRO sci­en­tist Penny Whet­ton said.

“It has been more un­cer­tain about how pre­cip­i­ta­tion will change in the north.”

The con­fer­ence heard that cli­mate change ap­peared to be track­ing at the high end of pro­jec­tions.

Car­bon diox­ide emis­sions and av­er­age global tem­per­a­tures were both at the mid to up­per end of the pre­dic­tions re­leased by the UN’s cli­mate change panel in 2007.

Sci­en­tists say the next round of com­puter sim­u­la­tions, which will be an­a­lysed in 2014, will pro­vide greater cli­mate cer­tainty.

Photo by JA­PAN ME­TE­O­RO­LOG­I­CAL AGENCY

Dev­as­tat­ing force: ex­perts are tip­ping less fre­quent but more ex­treme cy­clones such as Cy­clone Yasi for the Far North

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