Shirts made from the same polymer as
plastic bags.
Jeans infused with crushed jade. Garments constructed using
computerized knitting for superior ventilation, or made with cooling technology
designed for astronauts by NASA.
اضافة اعلان
As climate change brings more intense heat waves,
the next frontier in climate resilience is the
clothing we wear, with
innovations that promise to cool and dry the hot and sweaty masses. They could
make life more bearable for construction workers, farmers, soldiers, and others
who cannot retreat indoors as days and nights get hotter.
Clothing designed for heat is moving from a niche product
into the mainstream, said Lorna Hall, director of fashion intelligence for
WGSN, a company that tracks and forecasts consumer trends.
But the industry’s response to rising temperatures
also illustrates the challenges of adapting to climate change. The most
promising options tend to be the most expensive. Consumers must navigate
confusing or questionable claims. And improvements in one area almost always
entail trade-offs elsewhere.
Here is a look at some of the garments already
available, and others on their way — and what they reveal about the challenges
of dressing for a warming world.
The limits of just wearing less
In some ways, less is best
when dressing for heat, according to George Havenith, a professor of
environmental physiology at Loughborough University in
England.
“A lot of bare skin,” Havenith said. “It tends to
make quite a bit of difference.”
Witness the push to make shorts acceptable
officewear. Even unbuttoning a collar can help. During a heat wave this summer,
Spain’s prime minister, Pedro Sánchez, asked public officials and private
sector workers to stop wearing neckties, which he said would reduce the need
for air conditioning and thus save energy.
In the past five years, changes in weather alone
have increased sales of shorts and sandals by half a percentage point, while
reducing sales of fleece and outerwear by 1 percent, according to Evan Gold,
executive vice president at Planalytics, a company that quantifies the impact
of weather on consumer demand.
Given the size of the market those changes represent
a significant amount of money, Gold said.
Staying cool is not cheap
Whether clothing keeps you
cool revolves largely around breathability — the amount of air flow that
permeates the
fabric, carrying heat away from the skin. There are any number of
ways to improve air flow, including the selection of fabric, the space between
the fibers, and the thinness of the material.
But clothing must also be dense enough to shield
against ultraviolet rays. And it needs to be tough enough to endure multiple
washings.
Some cultures in
historically hot climates, such as in North Africa and South Asia, have
instructive traditions for dressing in heat, like loose-fitting clothes or
covering much of the body. Though recently, designers around the world have
been trying to solve the heat problem with technology.
Among the most affordable examples is Uniqlo’s
AIRism T-shirt ($15), which comes in a polyester-and-spandex version, and
another made of 71 percent cotton, mixed with 25 percent polyester and 4
percent spandex.
The polyester-spandex version is clingy, creating a
sensation uncomfortably close to wrapping one’s upper body in Saran wrap. The
cotton version, by contrast, feels pleasant at first, creating an initial
cooling effect. But when worn in the heat, it sticks to the skin, producing a
sensation akin to cold sweats. A spokesperson for Uniqlo said the shirt had
been positively received by customers.
Slightly higher up the cost curve, Dickies’ Cooling
Temp-iQ T-shirt ($20), a 50-50 blend of cotton and polyester, promises an
“INSTANT COOLING SENSATION.” A spokesperson for the company said it employed
“an advanced body temperature technology that is designed to either cool or
warm in response to your body’s signals.” But the garment, though comfortable
against the skin, created no perceptible cooling sensation, instant or
otherwise.
One shirt that had a noticeably cooling effect was
made by LifeLabs, a company that emerged from a research lab at Stanford
University. Its $49 CoolLife Tee is made from polyethylene, the same polymer
used in plastic bags. It produced a cool feeling, not unlike walking barefoot
on a tile floor.
Computerized knitting and spacesuits
For a similar price, Ministry of Supply, a company in Boston founded by
former Massachusetts Institute of Technology students, sells the Atlas Tee
($48). The shirt is constructed using computerized knitting, a technology
similar to 3D printing that makes it possible to create additional space
between the strands of material, according to Gihan Amarasiriwardena, the
company’s co-founder and president.
The result is a
garment that feels slightly thicker than a standard shirt, as if wearing light
padding. Yet it also feels cool, even under other garments.
But the process
means the shirts cannot yet be mass-produced, which means higher prices. Each
Atlas shirt costs Ministry of Supply $9.60 to produce, Amarasiriwardena said —
four times what it might cost a typical clothing manufacturer.
Other garment
makers use different high-tech tools.
Kontoor Brands, a
North Carolina-based company that owns Wrangler and Lee, said it will begin
selling “Insta-Cool” shirts in the
US next year with an updated version of a
technology called phase-change material, first designed by NASA to cool
astronauts. The shirts are already available in Asia.
The technology
involves printing ink made from wax and other materials on portions of the
interior of the shirt, which act as a heat sink, according to Dhruv Agarwal,
the company’s senior director for innovation, sustainability, and product
development. The approach creates a noticeable and lasting cooling effect,
based on a sample provided by the company.
Kontoor also sells
jeans in
Asia that are infused with bits of jade crushed into powder and
blended into the fabric. The idea is to transfer the cooling sensation of stone
into the garment, Agarwal said.
To wick or not to wick
Sweat is the body’s natural cooling mechanism. And it poses a complicated
challenge to manufacturers of cool clothing.
Most garments that
companies market as cooling also promise to keep their wearers dry by wicking
sweat away from the skin. But too much wicking can be counterproductive,
according to Glen Kenny, a professor of physiology at the University of Ottawa.
Sweat cools through
evaporation, a process that transfers heat from the body into the air. The
closer to the skin that evaporation takes place, the more heat energy it
consumes in the process; when clothing moves sweat away from the skin, it keeps
the body dry but renders evaporation less efficient at cooling, Kenny said.
“There’s a
misguided belief that wicking away that sweat from the skin is somehow going to
keep the body cool,” he said.
Sweat-wicking
clothing primarily makes people feel comfortable — a different goal from
cooling. Kenny recalled hearing from miners who tried to deal with the heat by
coming to their jobs wearing sweat-wicking undergarments. “It made the
situation worse,” he said.
Climate trade-offs
In some cases, making clothing better suited to heat can exacerbate other
climate problems.
One of the most
breathable natural fibers is cotton. But growing enough crop for around 0.5kg
of cotton fiber requires almost 1,324 liters of water in a good year, according
to data provided by the Agricultural Research Service at the
US Department of Agriculture (USDA).
The best type of
cotton for heat is often called Pima or Egyptian cotton, which makes garments
that are thinner and lighter. Yet growing Pima requires even more water than
lower-quality cotton, according to the USDA — in some cases, twice as much.
That trade-off
between breathability and sustainability is a conundrum, said Sara Kozlowski,
vice president at the Council of Fashion Designers of America, an industry
group.
Still, natural
fibers like cotton are at least biodegradable. Sweat-wicking polyester, by
comparison, is made from petroleum and can take decades or more to decompose —
another challenge for clothing manufacturers already under pressure from
environmentalists.
For designers, navigating those competing demands “is
incredibly hard,” Kozlowski said.
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