Sci­en­tists: Ozone-eat­ing emis­sions on the rise

The New Zealand Herald - - World - Seth Borenstein Na­ture. — AP

Some­thing strange is hap­pen­ing with a now-banned chem­i­cal that eats away at Earth’s pro­tec­tive ozone layer: Sci­en­tists say there’s more of it — not less — go­ing into the at­mos­phere and they don’t know where it is com­ing from.

When a hole in the ozone formed over Antarc­tica, coun­tries around the world in 1987 agreed to phase out sev­eral types of ozone-de­plet­ing chem­i­cals called chlo­roflu­o­ro­car­bons (CFCs). Pro­duc­tion was banned, emis­sions fell and the hole slowly shrank.

But start­ing in 2013, emis­sions of the sec­ond most com­mon kind started ris­ing, ac­cord­ing to a study in yes­ter­day’s jour­nal The chem­i­cal, called CFC11, was used for mak­ing foam, de­greas­ing stains and for re­frig­er­a­tion.

“It’s the most sur­pris­ing and un­ex­pected ob­ser­va­tion I’ve made in my 27 years” of mea­sure­ments, said study lead au­thor Stephen Montzka, a re­search chemist at the Na­tional Oceanic and At­mo­spheric Ad­min­is­tra­tion. “Emis­sions to­day are about the same as it was nearly 20 years ago,” he said.

Coun­tries have re­ported close to zero pro­duc­tion of the chem­i­cal since 2006 but the study found about 13,000 tonnes a year has been re­leased since 2013.

Some seeps out of foam and build­ings and ma­chines, but sci­en­tists say what they’re see­ing is much more than that.

Mea­sure­ments from a dozen mon­i­tors around the world sug­gest the emis­sions are com­ing from some­where around China, Mon­go­lia and the Koreas, ac­cord­ing to the study.

The chem­i­cal can be a byprod­uct in other chem­i­cal man­u­fac­tur­ing, but it is sup­posed to be cap­tured and re­cy­cled.

Ei­ther some­one’s mak­ing the banned com­pound or pro­duc­ing it as a byprod­uct but not cap­tur­ing and re­port­ing it as re­quired, Montzka said.

An out­side ex­pert, Ross Salaw­itch, an at­mo­spheric sci­en­tist at the Univer­sity of Mary­land, is less diplo­matic.

He calls it “rogue pro­duc­tion”. adding that if it con­tin­ues “the re­cov­ery of the ozone layer would be threat­ened”.

High in the at­mos­phere, ozone shields Earth from ul­tra­vi­o­let rays that cause skin can­cer, crop dam­age and other prob­lems.

Na­ture re­moves 2 per cent of the CFC11 out of the air each year, so con­cen­tra­tions of the chem­i­cal in the at­mos­phere are still fall­ing, but at a slower rate be­cause of the new emis­sions, Montzka said.

The chem­i­cal stays in the air for about 50 years.

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