when you're confronted with yet another choice:

當你面對另一個選擇時。

what kind of bag should you use?

你應該使用什麼樣的袋子？

If you've seen the images of plastic bags strewn across the ocean,

如果你看過塑膠袋散落在海洋上的畫面。

it might seem obvious that plastic is bad for the environment.

看上去很明顯，塑膠對環境是有害的。

Surely a paper bag or a cotton tote would be the better option.

當然，紙袋或棉布手提袋會是更好的選擇。

But is that really true?

但真的是這樣嗎？

Each of these three materials has a unique environmental impact

這三種材料對環境都有獨特的影響。

that's determined by its carbon footprint,

這是由其碳足跡決定的。

its potential to be reused and recycled, and its degradability.

其再利用和回收的潛力，以及其可降解性；

So, to get the full story on these grocery bags

所以，要想了解這些雜貨袋的完整故事，就必須要有一個完整的故事。

we need to look at how they're made,

我們需要看看他們是如何製造的。

how they're used, and where they ultimately go.

如何使用它們，以及它們最終的去向。

Let's start with plastic.

先說說塑膠吧。

The typical thin and flimsy plastic bag is made of high-density polyethylene,

典型的薄而易碎的塑膠袋是由高密度聚乙烯製成的。

commonly known as HDPE.

俗稱HDPE。

Producing this material requires extracting petroleum from the ground

生產這種材料需要從地下開採石油。

and applying extreme heat.

並施以極熱。

The resulting polymer resin is then transported

所得的聚合物樹脂然後被輸送到

alongside additional ingredients like titanium oxide and chalk

此外，還有氧化鈦和白堊等其他成分。

to a bag manufacturing plant.

到一家制袋廠。

Here, coal powered machines melt the materials down

在這裡，以煤為動力的機器將材料熔化。

and spin them into sheets of plastic,

並將它們旋成塑料片。

which are then folded into bags.

然後將其摺疊成袋。

By the time a bag reaches its final destination,

當一個袋子到達最終目的地時。

it's contributed an estimated 1.6 kg of carbon dioxide to the atmosphere.

它為大氣層貢獻了約1.6公斤的二氧化碳。

That's the same amount of carbon a car produces,

這和一輛汽車產生的碳量是一樣的。

driving a little over 6 kilometers.

開了6公里多一點。

But the alternatives actually possess a much larger carbon footprint.

但實際上，這些替代品擁有更大的碳足跡。

Paper is made from wood pulp,

紙是由木漿製成的。

and when you account for the carbon cost of removing trees from their ecosystems,

而當你考慮到將樹木從其生態系統中移除的碳成本。

a single paper bag can be responsible for about 5.5 kg of carbon dioxide.

一個紙袋可以產生約5.5公斤的二氧化碳。

Meanwhile, growing cotton is an extremely energy and water intensive process.

同時，種植棉花是一個極其耗費能源和水資源的過程。

The production of a single cotton tote

單一棉布手提包的生產

emits an estimated 272 kg of carbon dioxide.

排放的二氧化碳估計為272公斤。

When we compare carbon footprints, plastic bags are the clear winner.

當我們比較碳足跡時，塑膠袋是明顯的贏家。

But environmental impact is also determined by how the bag is used.

但環境影響也是由袋子的使用方式決定的。

Reusing or recycling these bags

重複使用或回收這些袋子

significantly offsets their environmental toll

顯著地抵消了其對環境的影響

by reducing demand for new production.

通過減少對新生產的需求。

To quantify that offset, we can divide the bag's carbon footprint

為了量化這種抵消，我們可以將袋子的碳足跡除以

by the number of times it's reused.

由重複使用的次數。

For example, if a typical paper bag is reused three times,

例如，如果一個普通紙袋重複使用三次。

it has a lower net impact than a single-use plastic bag.

它比一次性塑膠袋的淨影響更小。

The carbon footprint of a cotton tote can similarly be lowered,

棉布手提袋的碳足跡同樣可以降低。

if it's reused 131 times.

如果重複使用131次。

Of these three options, durable cloth totes are most likely to be reused.

在這三種選擇中，耐用的布袋最容易被重複使用。

Evidence shows paper bags are quickly discarded due to their tendency to tear.

證據顯示，紙袋由於容易撕裂，很快就會被丟棄。

This issue plagues HDPE plastic bags as well.

這個問題同樣困擾著HDPE塑膠袋。

But even when they're made to avoid tearing,

但即使是做了避免撕裂。

their widespread availability makes it easy to treat them as single-use items.

其廣泛的可用性使其很容易被視為一次性使用的物品。

Fortunately, researchers estimate that 40% of HDPE bags

幸運的是，研究人員估計，40%的HDPE袋

are reused at least once for throwing out waste.

至少重複使用一次，用於丟棄廢物。

Recycling these bags also offsets their carbon footprint,

回收這些袋子還可以抵消其碳足跡。

but it's not universally possible for each material.

但並不是每種材料都能普遍實現。

Many countries lack the infrastructure to efficiently recycle plastic bags.

許多國家缺乏有效回收塑膠袋的基礎設施。

Cotton totes are perhaps even more difficult to breakdown and process,

棉布手提袋或許更難分解和加工。

but since they're often reused for long periods,

但由於它們經常被長期重複使用。

they're still least likely to end up in landfills.

他們仍然是最不可能最終被填埋的。

Whenever these bags aren't recycled,

每當這些袋子沒有被回收的時候。

the third factor in calculating environmental impact comes into play:

計算環境影響的第三個因素是：

degradability.

降解性；

Since HDPE bags are heat-resistant and insoluble,

由於HDPE袋具有耐熱性和不溶性。

they stick around long after we're done with them.

他們堅持圍繞長後，我們與他們做。

Partially broken down plastic can circulate in ecosystems for centuries.

部分分解的塑膠可以在生態系統中循環數百年。

Cotton on the other hand degrades substantially in a matter of months,

另一方面，棉花在幾個月內就會大幅降解。

and paper bags break down completely in just 90 days.

而紙袋在90天內就會完全分解。

So, which bag should you use?

那麼，你應該用哪種袋子呢？

It turns out the most environmentally friendly bags

原來最環保的袋子

have features of several materials we've discussed.

具有我們討論過的幾種材料的特點。

They're durable and reusable, like cotton, but made of plastic,

它們耐用且可重複使用，像棉花一樣，但由塑膠製成。

which has a lower carbon footprint than cotton or paper.

它的碳足跡比棉花或紙張低。

These sturdy shopping bags consist of polyester, vinyl and other tough plastics,

這些堅固的購物袋由聚酯、乙烯基和其他堅韌的塑膠組成。

and are already used worldwide.

並已在全球範圍內使用。

Most importantly, they should last a lifetime—

最重要的是，它們應該持續一生--。

making them the best option for the planet, and your groceries.

使它們成為地球和您的食品雜貨的最佳選擇。