Truro Daily News - - COLCHESTER COUNTY -

In­creas­ing year-to-year vari­abil­ity in the en­vi­ron­ment is one of the big­gest changes we have been see­ing in At­lantic Canada, ac­cord­ing to a se­nior oceanog­ra­pher with DFO.

This in­cludes not only the tem­per­a­tures, but things like vari­abil­ity in the fresh­wa­ter out­flow, and the amount and tim­ing of ice com­ing out of the Arc­tic, says Dr. Pierre Pepin, who has stud­ied cli­mate change and pop­u­la­tion dy­nam­ics for most of his ca­reer.

Pepin stresses the dif­fer­ence be­tween cli­mate and the weather when dis­cussing cli­mate change.

He feels of­ten peo­ple have a ten­dency to as­sign what­ever is hap­pen­ing in a par­tic­u­lar weather sys­tem to cli­mate change, but ad­vises that it is prob­a­bly a com­bi­na­tion of cli­mate change and weather.

Vari­abil­ity, Pepin ex­plains, refers to how much the weather can vary from a des­ig­nated pe­riod of time to the next. In­creas­ing vari­abil­ity means it has be­come more dif­fi­cult to pre­dict the weather based on prece­dent, as well as an in­crease in the oc­cur­rence of ex­treme tem­per­a­tures and weather events.

“Gen­er­ally, in the past, you could say if last win­ter was harsh, you could say this win­ter was go­ing to be not that dif­fer­ent,” he ex­plained. “Well, now, it’s becoming much more dif­fi­cult to say how sim­i­lar or dif­fer­ent the win­ter from one year to the next will be.”

For ex­am­ple, win­ter sur­veys in re­cent years have found a fair bit of cold wa­ter in the Gulf of St. Lawrence but noth­ing un­usual, Pepin says. How­ever, this year, they have found the greatest amount of cold wa­ter in the Gulf of St. Lawrence in 24 years.

Ac­cord­ing to Pepin, what has made the moderate-term fore­cast more un­pre­dictable is an in­crease of en­ergy, cre­ated by global warm­ing, in the sys­tem.

“Those kinds of moderate-term fore­casts are a lot harder to come by be­cause there’s more en­ergy in the sys­tem, be­cause the planet is warm­ing there’s more en­ergy in the sys­tem,” he ex­plained. “And when you have more en­ergy in the sys­tem, your abil­ity to pre­dict how what hap­pens in one part of the world will in­flu­ence what hap­pens in your part of the world be­comes more dif­fi­cult.”

Dr. Norm Catto, head of geog­ra­phy at Me­mo­rial Univer­sity in St. John’s, agrees.

Catto said the in­creas­ing weather vari­abil­ity that At­lantic Canada faces is go­ing to be harder for the pub­lic to deal with than cli­mate change it­self.

For ex­am­ple, he ex­plains that if you knew ev­ery year was go­ing to fea­ture less snow than the last, then you can pre­pare ac­cord­ingly for that.

But that’s not how cli­mate change works.

In­stead, the amount of snow we re­ceive each year may fluc­tu­ate: one win­ter may fea­ture heavy snow­fall while the next there may be none.

It’s en­tirely un­pre­dictable.

That’s go­ing to make adapt­ing more dif­fi­cult for busi­nesses who de­pend on the snow, for ex­am­ple, or towns who are try­ing to bud­get how much to spend on snow clear­ing.

BE­LOW: A tour boat ap­proaches an ice­berg in 2018 off New­found­land’s North­ern Penin­sula.

ABOVE: Dr. Pierre Pepin is se­nior oceanog­ra­pher with Fish­eries and Oceans Canada.

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