Sea change

The Compass - - EDITORIAL -

We know it well. It’s right out­side our door, threaded into our daily lives - so, when things change in the At­lantic Ocean, we pay at­ten­tion.

For fish­eries work­ers, it’s cen­tral to their liveli­hoods. The con­di­tion of the ocean - tem­per­a­tures, salin­ity, tur­bid­ity and cur­rents - can cause booms and busts in fish species the in­dus­try de­pends on.

For the rest of us, it’s equally part of daily life - and not, as those fool­ish ads for salt­wa­ter nasal sprays seem to claim, be­cause the sea air means no one who lives near the ocean ever gets a stuffy nose.

The ocean is our great mod­er­a­tor; a huge and sta­ble tem­per­a­ture sink, it cools our sum­mers and warms our win­ters, gen­er­ates our fog and builds our winds. Whole weather pat­terns change as they cruise across open water, snow chang­ing to rain, sun chang­ing to grey - and with the right land­ward breeze, tem­per­a­tures drop­ping by five de­grees or more in the equiv­a­lent of a few min­utes’ walk.

While we’re used to the ocean tak­ing pretty much any­thing we dish out - from mu­nic­i­pal pol­lu­tants to over­fish­ing, to cli­mate pol­lu­tion caus­ing ris­ing ocean tem­per­a­tures and in­creased acid­ity - it’s worth keep­ing a weather eye on our wa­tery neigh­bour.

Ear­lier this month, sci­en­tists talked about the in­crease that’s been show­ing up in ocean tem­per­a­tures off Nova Sco­tia - it’s not a record high tem­per­a­ture, but for the last decade, tem­per­a­tures on the Sco­tian Shelf hav­ing been ris­ing, and in 2015 (the last year for which full data has been col­lected) stood at three de­grees above the 30-year av­er­age. (Three de­grees doesn’t sound like much, but bear in mind the sheer vol­ume of water in­volved and the mas­sive amount of en­ergy it would take to in­crease that vol­ume of salt water by that many de­grees.)

In Oc­to­ber, 32 kilo­me­tres off the coast of the prov­ince, the water tem­per­a­ture on the bot­tom was 11 de­grees, far higher than in past years. The sug­ges­tion now? That a warm­ing Gulf Stream is push­ing fur­ther north, chang­ing its di­rec­tion and de­flect­ing the south­ern-run­ning Labrador current, now car­ry­ing fresher water as Arc­tic ice melts, some­where around the tail of the Grand Banks.

In some ways, re­search from New­found­land and Labrador echoes that con­clu­sion, though its ocean tem­per­a­tures in 2015 were closer to nor­mal than in the Sco­tian Shelf. Lots of num­bers, but what does it all mean? Sci­en­tists look­ing at the Nova Sco­tia num­bers cau­tion that ocean tem­per­a­tures are of­ten cycli­cal - but when we’re the mice on­shore, look­ing out at the neig­bour­ing ele­phant of the At­lantic, you have to be pay­ing at­ten­tion.

New re­search in the jour­nal Sci­ence Ad­vances sug­gests con­tin­ued and more se­vere change in At­lantic cur­rents could be com­ing with in­creased lev­els of car­bon diox­ide in the at­mos­phere. We’d bet­ter watch care­fully - be­cause we’re on the cost, and on the front line.

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