Arc­tic sea ice once again shows con­sid­er­able melt­ing

Iran Daily - - Cultural Heritage & Environment -

This Septem­ber, the ex­tent of Arc­tic sea ice shrank to roughly 4.7 mil­lion square kilo­me­ters, as was de­ter­mined by re­searchers at the Al­fred We­gener In­sti­tute, the Univer­sity of Bre­men and Univer­sität Ham­burg.

Though slightly larger than last year, the min­i­mum sea ice ex­tent 2017 is av­er­age for the past ten years and far be­low the num­bers from 1979 to 2006. The North­east Pas­sage was tra­vers­a­ble for ships with­out the need for ice­break­ers, ac­cord­ing to phys.org.

The sea ice in the Arc­tic is con­sid­ered a crit­i­cal el­e­ment in cli­mate pro­cesses, and a valu­able early-warn­ing sys­tem for global warm­ing.

Ac­cord­ingly, the Septem­ber min­i­mum ex­tent is an im­por­tant in­di­ca­tor of cli­mate change. De­spite an es­pe­cially warm win­ter, the cur­rent ex­tent of sea ice does not rep­re­sent a new record low; nev­er­the­less, the amount of ice loss is mas­sive.

As sea-ice physi­cist Mar­cel Ni­co­laus from the Al­fred We­gener In­sti­tute, Helmholtz Cen­ter for Po­lar and Ma­rine Re­search (AWI) ex­plains, “This year’s sea ice ex­tent is again on a very low level: The ob­served Septem­ber value of the past eleven years has con­sis­tently been lower than in any of the pre­vi­ous years.”

This win­ter, the Arc­tic re­mained un­usu­ally warm, and the sea-ice cov­er­age in March was lower than in any March be­fore.

Lars Kaleschke from Univer­sität Ham­burg’s Cen­ter for Earth Sys­tem Re­search and Sus­tain­abil­ity stressed, “Thanks to the rel­a­tively cold sum­mer, the sea ice man­aged to bounce back some­what, but this year’s Septem­ber min­i­mum is by no means a good sign.

“Though the amount of sea ice is of course sub­ject to nat­u­ral fluc­tu­a­tions, the long-term de­cline is ob­vi­ous.

“For com­par­i­son, the sum­mer­time min­i­mums in the 1970s and 1980s were roughly seven mil­lion square kilo­me­ters.”

The sea-ice cov­ered area is mea­sured with the help of satel­lites. The high-res­o­lu­tion mi­crowave satel­lite data are jointly pro­vided by the Univer­sity of Bre­men and Univer­sität Ham­burg. They al­low to pre­cisely an­a­lyze the daily sea-ice ex­tent over the en­tire Arc­tic. That’s par­tic­u­larly im­por­tant for the ship­ping in­dus­try.

Gun­nar Spreen from the Univer­sity of Bre­men’s In­sti­tute of En­vi­ron­men­tal Physics said, this sum­mer, the North­east Pas­sage along the Rus­sian coast could be used with­out the need for ice­break­ers, and many ships also used the North­west Pas­sage.

STE­FAN HEN­DRICKS/AL­FRED-WE­GENER-IN­STI­TUT

Newspapers in English

Newspapers from Iran

© PressReader. All rights reserved.