Which bag should you use? - Luka Seamus Wright and Imogen Ellen Napper
-
0:08 - 0:11You’ve filled up your cart and made
it to the front of the grocery line -
0:11 - 0:14when you’re confronted
with yet another choice: -
0:14 - 0:17what kind of bag should you use?
-
0:17 - 0:20If you’ve seen the images of plastic bags
strewn across the ocean, -
0:20 - 0:23it might seem obvious that plastic
is bad for the environment. -
0:23 - 0:27Surely a paper bag or a cotton tote
would be the better option. -
0:27 - 0:29But is that really true?
-
0:29 - 0:33Each of these three materials
has a unique environmental impact -
0:33 - 0:35that’s determined by its carbon footprint,
-
0:35 - 0:39its potential to be reused and recycled,
and its degradability. -
0:39 - 0:42So, to get the full story
on these grocery bags -
0:42 - 0:44we need to look at how they’re made,
-
0:44 - 0:47how they’re used,
and where they ultimately go. -
0:47 - 0:50Let’s start with plastic.
-
0:50 - 0:54The typical thin and flimsy plastic bag
is made of high-density polyethylene, -
0:54 - 0:57commonly known as HDPE.
-
0:57 - 1:01Producing this material requires
extracting petroleum from the ground -
1:01 - 1:03and applying extreme heat.
-
1:03 - 1:06The resulting polymer resin
is then transported -
1:06 - 1:10alongside additional ingredients
like titanium oxide and chalk -
1:10 - 1:13to a bag manufacturing plant.
-
1:13 - 1:16Here, coal powered machines
melt the materials down -
1:16 - 1:18and spin them into sheets of plastic,
-
1:18 - 1:21which are then folded into bags.
-
1:21 - 1:23By the time a bag reaches
its final destination, -
1:23 - 1:29it’s contributed an estimated 1.6 kg
of carbon dioxide to the atmosphere. -
1:29 - 1:32That’s the same amount of carbon
a car produces, -
1:32 - 1:34driving a little over 6 kilometers.
-
1:34 - 1:39But the alternatives actually possess
a much larger carbon footprint. -
1:39 - 1:41Paper is made from wood pulp,
-
1:41 - 1:45and when you account for the carbon cost
of removing trees from their ecosystems, -
1:45 - 1:51a single paper bag can be responsible
for about 5.5 kg of carbon dioxide. -
1:51 - 1:56Meanwhile, growing cotton is an extremely
energy and water intensive process. -
1:56 - 1:59The production of a single cotton tote
-
1:59 - 2:04emits an estimated 272 kg
of carbon dioxide. -
2:04 - 2:09When we compare carbon footprints,
plastic bags are the clear winner. -
2:09 - 2:13But environmental impact
is also determined by how the bag is used. -
2:13 - 2:16Reusing or recycling these bags
-
2:16 - 2:18significantly offsets
their environmental toll -
2:18 - 2:21by reducing demand for new production.
-
2:21 - 2:25To quantify that offset, we can divide
the bag’s carbon footprint -
2:25 - 2:28by the number of times it’s reused.
-
2:28 - 2:32For example, if a typical paper bag
is reused three times, -
2:32 - 2:36it has a lower net impact
than a single-use plastic bag. -
2:36 - 2:40The carbon footprint of a cotton tote
can similarly be lowered, -
2:40 - 2:43if it’s reused 131 times.
-
2:43 - 2:48Of these three options, durable cloth
totes are most likely to be reused. -
2:48 - 2:52Evidence shows paper bags are quickly
discarded due to their tendency to tear. -
2:52 - 2:55This issue plagues HDPE
plastic bags as well. -
2:55 - 2:58But even when they’re made
to avoid tearing, -
2:58 - 3:02their widespread availability makes
it easy to treat them as single-use items. -
3:02 - 3:07Fortunately, researchers estimate
that 40% of HDPE bags -
3:07 - 3:11are reused at least once
for throwing out waste. -
3:11 - 3:14Recycling these bags also offsets
their carbon footprint, -
3:14 - 3:17but it’s not universally possible
for each material. -
3:17 - 3:22Many countries lack the infrastructure
to efficiently recycle plastic bags. -
3:22 - 3:25Cotton totes are perhaps even more
difficult to breakdown and process, -
3:25 - 3:28but since they’re often reused
for long periods, -
3:28 - 3:31they’re still least likely
to end up in landfills. -
3:31 - 3:33Whenever these bags aren’t recycled,
-
3:33 - 3:37the third factor in calculating
environmental impact comes into play: -
3:37 - 3:39degradability.
-
3:39 - 3:43Since HDPE bags are heat-resistant
and insoluble, -
3:43 - 3:45they stick around long after we’re done
with them. -
3:45 - 3:50Partially broken down plastic
can circulate in ecosystems for centuries. -
3:50 - 3:54Cotton on the other hand degrades
substantially in a matter of months, -
3:54 - 3:58and paper bags break down
completely in just 90 days. -
3:58 - 4:01So, which bag should you use?
-
4:01 - 4:03It turns out the most
environmentally friendly bags -
4:03 - 4:07have features of several materials
we've discussed. -
4:07 - 4:11They’re durable and reusable, like cotton,
but made of plastic, -
4:11 - 4:15which has a lower carbon footprint
than cotton or paper. -
4:15 - 4:20These sturdy shopping bags consist of
polyester, vinyl and other tough plastics, -
4:20 - 4:23and are already used worldwide.
-
4:23 - 4:26Most importantly,
they should last a lifetime— -
4:26 - 4:30making them the best option
for the planet, and your groceries.
- Title:
- Which bag should you use? - Luka Seamus Wright and Imogen Ellen Napper
- Speaker:
- Luka Seamus Wright and Imogen Ellen Napper
- Description:
-
View full lesson: https://ed.ted.com/lessons/which-bag-should-you-use-luka-seamus-wright-and-imogen-ellen-napper
You’ve filled up your cart and made it to the front of the grocery line when you’re confronted with yet another choice: what kind of bag should you use? It might seem obvious that plastic is bad for the environment, and that a paper bag or a cotton tote would be the better option. But is that really true? Luka Seamus Wright and Imogen Ellen Napper explore the environmental impact of each material.
Lesson by Luka Seamus Wright & Imogen Ellen Napper, directed by JodyPrody.
- Video Language:
- English
- Team:
- closed TED
- Project:
- TED-Ed
- Duration:
- 04:31
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