Quakes help speed up sea-level rise in ar­eas

Kapiti Observer - - WHAT’S ON - GED CANN

The im­pact of sea-level rises could dou­ble in some ar­eas as a re­sult of sink­ing land lev­els, ac­cord­ing to a Vic­to­ria Uni­ver­sity study.

While the find­ings had the po­ten­tial to wipe thou­sands of dol­lars off the value of some sea­side prop­er­ties, for some it will be mu­sic to their ears, with shore­line up­lift in other ar­eas negat­ing sea-level rises.

Study co-au­thor Pro­fes­sor Tim Stern said this new in­for­ma­tion could be used by home­own­ers to de­cide land value, by the gov­ern­ment to plan mit­i­ga­tion mea­sures and the in­sur­ance in­dus­try to set pre­mi­ums.

‘‘In parts of the North Is­land the ac­tual sur­face of the land is go­ing down 3 mil­lime­tres in re­la­tion to the cen­tre of the Earth, you ef­fec­tively dou­ble the global rate [of sea-level rise].’’

In­sur­ance Coun­cil chief ex­ec­u­tive Tim Grafton said sealevel rise was on in­sur­ance com­pa­nies’ radars, and was one of the risks in­sur­ers took into ac­count.

‘‘In­sur­ers draw on all avail­able data points to in­form them­selves about risks.’’

Grafton had not seen the re­ports’ full find­ings, but said he would be in­ter­ested in the pro­jec­tions.

Stern, from the School of En­vi­ron­ment and Earth Sciences, said the global sealevel change due to global warm­ing and the melt­ing of po­lar ice­caps was pro­jected to be around 3mm a year.

‘‘The rate in New Zealand is be­ing mea­sured at about 1.5mm [a year] by tide gauges.’’

The study used 15 years of GPS data to pre­dict land move­ments.

Kapiti Coun­cil pre­vi­ously in­cluded coastal haz­ard in­for­ma­tion in res­i­dents’ Land In­for­ma­tion Mem­o­ran­dums (LIMS), but were forced to stop af­ter res­i­dents lit­i­gated over lost prop­erty value.

Stern said banks and in­sur­ers would find the in­for­ma­tion in­valu­able.

‘‘If they have a bet­ter knowl­edge of what their par­tic­u­lar area of the coast­line is do­ing they will be in a much bet­ter shape to make good pol­icy.’’

As the study con­tin­ues and the data pool got larger, Stern said the mar­gin of er­ror be­came smaller.

The scope of the study is lim­ited to ar­eas with GPS sta­tions.

A Vic­to­ria Uni­ver­sity im­age shows what could hap­pen to sea-level in Welling­ton if av­er­age tem­per­a­tures rise by 2 de­grees Cel­sius this cen­tury com­pared with pre-in­dus­trial lev­els.

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