Pa­per or plas­tic? No sim­ple answer; choice of bag likely mat­ters less than what’s in­side

The Buffalo News - - NATIONAL NEWS - By Brad Plumer

WASH­ING­TON – The de­ci­sion by New York State to ban sin­gle-use plas­tic bags from re­tail stores makes it a good time to re­visit ev­ery­one’s fa­vorite en­vi­ron­men­tal quandary: pa­per or plas­tic?

Un­for­tu­nately, there’s no sim­ple answer on whether pa­per or plas­tic bags are bet­ter for the en­vi­ron­ment. They both have down­sides, but there are a few broad les­sons to keep in mind when you are at the gro­cery store.

Plas­tic bags, which of­ten take cen­turies to de­com­pose, can cre­ate a dread­ful waste prob­lem even though they’re far from the largest source of plas­tic waste in Amer­ica – about 12 per­cent of the to­tal.

On the other hand, pa­per bags typ­i­cally re­quire more en­ergy and green­house gas emis­sions to pro­duce, which isn’t great from a global warm­ing stand­point.

Re­us­able bags can be a de­cent com­pro­mise, pro­vided you hold onto them and use them of­ten. Ul­ti­mately, though, what you put in­side the bag, par­tic­u­larly your food choices, will most likely mat­ter a lot more for the en­vi­ron­ment than what type of bag you use.

The trou­ble with plas­tic bags Amer­i­can shop­pers use more than 100 bil­lion light­weight poly­eth­yl­ene plas­tic bags each year, and only a small por­tion are ever re­cy­cled. Most re­cy­cling cen­ters can’t deal with them – they just clog up the ma­chin­ery – and so the ma­jor­ity of plas­tic bags end up in land­fills, where they can take up to 1,000 years to de­grade.

To be fair, a plas­tic bag doesn’t cause too much harm sit­ting in a land­fill. The big­ger prob­lem arises when peo­ple don’t dis­pose of their bags prop­erly, and the plas­tic ends up flut­ter­ing around in the wild, clog­ging up wa­ter­ways and threat­en­ing wildlife.

San Jose, Calif., for in­stance, found that plas­tic bags made up about 12 per­cent of the lit­ter in its creeks be­fore im­ple­ment­ing a lo­cal bag ban in 2012. And, just last week, a dead sperm whale washed ashore in In­done­sia with two dozen plas­tic bags in its gut, along with other trash.

So, even though plas­tic bags are only a small frac­tion of Amer­ica’s over­all plas­tic trash, they’ve be­come a highly vis­i­ble sign of waste.

The trou­ble with pa­per bags

So does that mean pa­per bags, which de­grade more eas­ily, are a bet­ter op­tion? Not nec­es­sar­ily. Cli­mate change has be­come the big­gest en­vi­ron­men­tal is­sue of our time, so it’s worth look­ing at things from an emis­sions stand­point. And on that score, pa­per bags fare worse.

Even though pa­per bags are made from trees, which are, in the­ory, a re­new­able re­source, it takes sig­nif­i­cantly more en­ergy to cre­ate pulp and man­u­fac­ture a pa­per bag than it does to make a sin­gle-use plas­tic bag from oil.

Back in 2011, Bri­tain’s En­vi­ron­ment Agency con­ducted a life-cy­cle as­sess­ment of var­i­ous bag op­tions, look­ing at ev­ery step of the pro­duc­tion process. The con­clu­sion? You’d have to re­use a pa­per bag at least three times be­fore its en­vi­ron­men­tal im­pact equaled that of a high-den­sity poly­eth­yl­ene plas­tic bag used only once. And if plas­tic bags were reused re­peat­edly, they looked even bet­ter. Pa­per bags can more eas­ily be re­cy­cled or even com­posted, but the British study found that even th­ese ac­tions didn’t make a huge dif­fer­ence in the broader anal­y­sis. Un­less you’re reusing your pa­per bags a lot, they look like a poorer op­tion from a global warm­ing stand­point.

Re­us­able bags are a de­cent op­tion – if you ac­tu­ally re­use them

That same British anal­y­sis also looked into re­us­able op­tions, like heav­ier, more durable plas­tic bags or cot­ton bags. And it found that th­ese are only sus­tain­able op­tions if you use them fre­quently.

Mak­ing a cot­ton shop­ping bag is hardly cost-free. Grow­ing cot­ton re­quires a fair bit of en­ergy, land, fer­til­izer and pes­ti­cides, which can have all sorts of en­vi­ron­men­tal ef­fects – from green­house gas emis­sions to ni­tro­gen pol­lu­tion in wa­ter­ways.

The study found that an avid shop­per would have to re­use his or her cot­ton bag 131 times be­fore it had a smaller global warm­ing im­pact than a light­weight plas­tic bag used only once. And, de­pend­ing on the make, more durable plas­tic bags would have to be used at least 4 to 11 times be­fore they made up for their heftier upfront cli­mate costs.

So if you’re go­ing to opt for a re­us­able bag for en­vi­ron­men­tal rea­sons, make sure you ac­tu­ally re­use it – of­ten. What’s in the bag mat­ters more It never hurts to think about bag choices. But keep in mind that if you’re go­ing to the gro­cery store, the food you pur­chase and place in that bag prob­a­bly has a vastly big­ger ef­fect on the en­vi­ron­ment than what­ever you use to haul it home.

Our global food sys­tem, af­ter all, is re­spon­si­ble for one-quar­ter of hu­man­ity’s planet-warm­ing green­house gas emis­sions – with meat and dairy hav­ing a dis­pro­por­tion­ately large im­pact. By con­trast, pack­ag­ing makes up only about 5 per­cent of the food sys­tem’s foot­print. Com­pared with, say, the ef­fects of clear­ing away vast swathes of for­est to grow feed or raise live­stock, our bags are a much smaller deal.

Put an­other way, a pound of beef bought at the su­per­mar­ket will have roughly 25 times the global warm­ing im­pact as the dis­pos­able plas­tic bag it’s car­ried in. So if you’re look­ing for ways to slim down your per­sonal car­bon foot­print, tak­ing a closer look at your di­etary choices isn’t a bad place to start.

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