Synthetic vs. Natural Fibers for Outdoor Clothing and Equipment
JUMP TO: NATURAL FIBERS | SYNTHETIC FIBERS | WHAT’S THE SUSTAINABLE CHOICE?
Author: Steve Edgerton | Updated: May 27, 2023
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The fibers found in outdoor apparel fall into two broad categories: natural and synthetic.
Natural fibers come from plant or animal sources, while synthetic fibers are derived from petrochemicals. When comparing the sustainability credentials of natural vs. synthetic fibers, it is often assumed that natural fibers win out. In many ways, they do: natural fibers are biodegradable, non-toxic, and renewable.
But, of course, the reality of sustainable fibers is not so clear-cut. Just as natural and synthetic fibers have their own pros and cons in terms of outdoor performance, each has its own pros and cons when it comes to sustainability and their impact on the environment.
For those of us looking to minimize our impact by investing in sustainable outdoor apparel and gear, this ambiguity makes it difficult to know if we are doing the right thing. We hope to make that easier with this guide to sustainable fibers.
SUSTAINABILITY OF NATURAL FIBERS
JUMP TO: WOOL | COTTON | HEMP | BAMBOO | EUCALYPTUS
Because they are biodegradable, non-toxic, renewable, and, well, natural, natural fibers have an eco-friendly veneer. But they are not without their problems. Let’s take a closer look at the sustainability cred of some of the most popular natural fibers.
Wool
Wool is sourced from many animals, notably sheep, llamas, alpacas, and goats. Merino wool (from merino sheep) is particularly favored for hiking and other outdoor sports thanks to its softness, insulation, odor resistance, and moisture-wicking characteristics.
Wool has an eco-friendly reputation, but this is largely a product of highly successful industry greenwashing campaigns. In fact, the Higg Material Sustainability Index (an index measuring climate impacts, water pollution/use, fossil fuel use, and chemical composition to measure material sustainability) ranks wool as one of the most environmentally impactful fibers to produce.
SUSTAINABILITY PROS:
Wool is renewable and biodegradable. It can be incorporated back into natural biological cycles if disposed of appropriately.
Wool contains no toxic chemicals or microplastics.
Thanks to its odor resistance, wool requires less frequent washing than synthetics or even other natural fibers. So theoretically, wool apparel can require less water and energy to maintain.
SUSTAINABILITY CONS:
Wool production is a land and resource-intensive endeavor. Half of the planet is dedicated to agriculture, with 77% of that land dedicated to grazing cattle, sheep, and goats.
Wool-bearing animals like sheep are ruminants: their particular digestive processes release significant amounts of methane — a greenhouse gas 86 times more potent than carbon dioxide. Small ruminants, like sheep and goats, produce 474 million metric tons of CO2 annually: about the equivalent of taking 103 million cars off the roads for a year.
Growing global demand for wool has also resulted in overgrazing and the eventual desertification of important grassland ecosystems throughout Australia, New Zealand, South Africa, and beyond.
Cotton
Though not the finest choice for highly aerobic sports or backcountry outings, cotton stands out for its comfort and durability. It is one of the most versatile and widely used fibers on the planet.
Unlike wool, cotton hasn’t captivated consumers as being a particularly ecologically friendly natural fiber. But again, the reality is nuanced. Different agricultural practices and different types of cotton mean there is a remarkable variety in the potential environmental impact of this ubiquitous fiber.
SUSTAINABILITY PROS:
Cotton is biodegradable and renewable. It grows well in diverse regions around the world.
Cotton does not contain toxic chemicals or microplastics.
Cotton is durable, more so than wool, and on par with many synthetics.
Organic and regenerative growing practices can dramatically improve the sustainability of cotton.
SUSTAINABILITY CONS:
Growing cotton is water intensive. Over 2,700 liters of water are used to produce the conventional cotton needed for a single t-shirt.
Conventional cotton crops are treated with enormous quantities of pesticides that pollute water and harm biodiversity.
Organic cotton uses significantly less water and pesticides than conventionally grown cotton. But organic farming is less productive than conventional methods, demanding more land to produce equivalent quantities, so these benefits are often overstated.
Hemp
Hemp is perhaps best known as the non-psychoactive cousin of marijuana. Because it is technically a cannabis plant, growing and using hemp fiber was limited in recent history, thanks to its designation as a Controlled Substance in the US.
Hemp was sensibly delisted as a Controlled Substance in 2018, fueling the fiber’s growth into one of the more promising sustainable fibers. Outdoor brands like REI Co-op, Patagonia, and prAna increasingly use hemp in their garments due to its durability, versatility, insulation, odor resistance, and relatively low environmental impact.
SUSTAINABILITY PROS:
Hemp grows like a, er… weed. It can produce double the fiber yield per hectare compared to cotton.
Hemp is productive while requiring relatively little irrigation, fertilizer, and pesticides.
Hemp is biodegradable, recyclable, and non-toxic.
Hemp is extremely durable, extending the life of garments.
SUSTAINABILITY CONS:
Processing hemp stalk in usable fiber is energy intensive. It can be done mechanically, but many companies process hemp chemically with toxic pollutants.
Hemp is bulky and heavy, so transporting it is inefficient and fuel-intensive.
Hemp fibers are quite stiff and not as comfortable on the skin as cotton or merino wool. Blending it with less sustainable fibers is usually necessary.
Bamboo
Bamboo is another natural fiber experiencing a boom in popularity. On the surface, it seems like a sustainability no-brainer. Bamboo, a type of grass, grows ridiculously fast (over 2 feet per day — seriously). It can also do this with little to no fertilizer, irrigation, or pesticides.
Bamboo can be processed mechanically, relying on natural enzymes rather than chemicals to break down the lignin. The resulting fiber, called bamboo linen, is quite sustainable. But it is time and labor-intensive to produce, and therefore very expensive. Most bamboo is transformed into a semi-synthetic fiber called viscose rayon through a toxic and dangerous chemical process.
Bamboo can be processed into lyocell (marketed under the brand name Tencel™) through a more sustainable process. Lyocell is another sustainable fiber outdoor brands are moving to thanks to its soft, breathable, moisture-wicking, and thermal regulating properties.
SUSTAINABILITY PROS:
Bamboo is hyper-renewable. Just like a suburban lawn, bamboo grows back after it is cut. Harvesting it does not disturb the soil, limiting erosion and soil degradation.
Bamboo is a carbon sink. It can potentially absorb significantly more carbon than an equivalent-sized stand of trees.
Bamboo is biodegradable, even when processed into “semi-synthetic” cellulosic fibers like bamboo rayon or bamboo lyocell.
SUSTAINABILITY CONS:
The process of turning bamboo into rayon is extremely toxic. It relies on the use of carbon disulfide. Workers in viscose rayon factories are regularly exposed to unsafe levels of the chemical, which has resulted in poisoning caused insanity, nerve damage, Parkinson’s disease, and cardiovascular issues.
Half of the toxic waste of rayon production is not recaptured, polluting and poisoning the atmosphere and aquatic ecosystems.
Bamboo production is contributing to the destruction of critical rainforest ecosystems throughout Asia.
Eucalyptus
Eucalyptus trees grow fast, with little to no need for irrigation, fertilizer, or pesticides. Like bamboo, the cellulose fiber from eucalyptus trees can be pulped and processed into lyocell. Among all the plant-based inputs used in lyocell, eucalyptus appears to offer the best quality fiber while producing the least amount of waste.
Tencel, the most popular brand of lyocell fiber, is now championed by top sustainable outdoor brands like Patagonia and Houdini. Eucalyptus-based Tencel is likely one of the more sustainable natural fibers, but a lot depends on how and where the eucalyptus trees are grown and harvested.
SUSTAINABILITY PROS:
Eucalyptus trees are a low-input, low-impact, and high-yielding crop.
Eucalyptus is non-toxic and biodegradable, even when processed into lyocell.
Eucalyptus Tencel fiber is sourced from farms certified by the Forest Stewardship Council (FSC). Unlike viscose rayon, it is processed in a non-toxic, closed-loop process that does not release toxic chemicals into waterways and the atmosphere.
SUSTAINABILITY CONS:
Eucalyptus is not always grown sustainably, with farms often clearing natural forests and peatlands — vital planetary carbon sinks. Look for eucalyptus certified by the FSC or PEFC-certified.
Eucalyptus-based Tencel is often blended with other fibers that do not always share its low-impact, biodegradable, microplastic-free qualities.
SUSTAINABILITY OF SYNTHETIC FIBERS
JUMP TO: POLYESTER | NYLON | DYNEEMA
Synthetic fibers have resulted in astounding advancements in outdoor gear and apparel. Not 100 years ago, mountaineers and explorers would labor under the weight of canvas tents and bags, decked out in scratchy wool, useless cotton, and clumsy leather boots.
Without the waterproof and ultralight gear made possible by petroleum-based synthetic fabrics, most of us would not even consider subjecting ourselves to that kind of drudgery. Responsibly used, synthetics may offer certain sustainable benefits that could justify our continued use of these high-performing fibers. But this requires us to also address the profound impact these materials have on our planet.
Polyester
Polyester is a term applied to a group of polymers created by combining petroleum-based ethylene glycol with terephthalic acid. Polyethylene terephthalate is the most popular type of polyester: it is used widely in technical apparel, tents, sleeping bags, and most single-use plastics.
SUSTAINABILITY PROS:
Polyester is durable. It doesn’t shrink or lose shape like natural fibers. It is also stain resistant and can be washed effectively at lower temperatures. Well-built polyester gear and apparel will last a long time.
Polyester requires less land and water to produce than many natural fibers like wool and cotton. This theoretically frees up land for conservation or production of essential food crops.
SUSTAINABILITY CONS:
Polyester is not renewable or biodegradable. It is often recyclable, but the quality degrades with each cycle. All the polyester on the planet will ultimately end up in landfills or polluting forests and oceans for thousands and thousands of years.
Polyester sheds plastic microfibers. These tiny plastics are too small to be caught in water treatment facilities. Nearly two million tonnes of microfibers wash into our waterways annually, poisoning wildlife and humans.
Recycled polyester is better, but even that has problems. For example, polyester fibers processed from plastic water bottles and marine plastic waste can’t be recycled again. It may even be sustaining the demand for single-use plastics: exacerbating the problems it seeks to address.
Nylon
Nylon was invented at the advent of World War II, the first fully synthetic fiber ever developed. It is created by putting crude oil through an energy-intensive chemical process, transforming it into large polymer chips. These polymers are melted and shredded into the stretchy, strong, and versatile fiber now found in raingear, ultralight tents, and backpacks.
SUSTAINABILITY PROS:
Nylon is strong and durable, even more so than polyester. It is often added in small quantities to dramatically improve the durability of merino wool apparel.
Unlike polyester, nylon is infinitely recyclable without degradation in quality. ECONYL® is a regenerated nylon product made from discarded nylon fishing nets and carpets. Many outdoor brands now use ECONYL over virgin nylon.
SUSTAINABILITY CONS:
Even 100% recycled nylon like ECONYL sheds polluting microplastics and will never biodegrade.
Nylon is made from crude oil, extracted and produced by the most polluting industry on the planet. Turning oil into nylon is energy intensive and releases nitrous oxide, one of the most potent greenhouse gasses.
Dyneema
Dyneema is a ridiculously light, ridiculously strong fiber. It is used in many industrial applications and has since become the darling of ultralight gear manufacturers. Most commonly found in tents and packs, brands are beginning to integrate Dyneema into everything from rain jackets to running shoes.
Dyneema is produced exclusively by DSM, a Netherlands-based materials manufacturer. Conventional Dyneema is sourced from fossil fuel-based polyethylene, but DSM recently unveiled a bio-based Dyneema that uses wood pulp rather than fossil fuels to produce ethylene.
SUSTAINABILITY PROS:
The durability of Dyneema fiber is unbeatable. Because it is also lightweight, waterproof, and UV-resistant, Dyneema is ideal for outdoor gear like packs, tents, and ropes. It is expensive but will last far longer than gear made from nylon or polyester.
Bio-based Dyneema is a semi–synthetic, eliminating reliance on fossil fuels. It represents a 90% reduction in CO2 emission from conventional Dyneema while offering equivalent performance.
SUSTAINABILITY CONS:
Until recently, conventional Dyneema was not recyclable. Even now, it can only be “downcycled” into less valuable products and is not biodegradable.
Dyneema is energy-intensive to produce, expensive, and only a viable replacement for other fibers for certain applications.
NATURAL VS. SYNTHETIC: WHAT’S THE SUSTAINABLE CHOICE?
Unfortunately, there is no straightforward answer to identifying the most sustainable fibers. The problems solved and created by natural and synthetic fibers are often paradoxical and seemingly intractable: both categories have significant but different consequences.
That said, there are a few broad conclusions we can draw. Overall, Tencel, recycled nylon, hemp, Dyneema, organic cotton, and organic, recycled, and humanely raised wool earn higher sustainability marks. Conversely, it is worth making an effort to avoid or significantly reduce your use of rayon, conventional cotton, most wool, and virgin polyester and nylon.
In the future, we are excited to see how materials innovation may help us move away from synthetics entirely. Biopolymers created from algae, wood pulp, agricultural by-products, and fungi may one day facilitate outdoor gear that performs like synthetics while being renewable, non-polluting, and biodegradable.
But remember, sustainability is often context dependent. Different fibers, both natural and synthetic, can be more or less sustainable depending on how they are produced and how they are used.
So, with a good understanding of the environmental impacts of different fibers, here are a couple of tips to help you make sustainable choices.
DURABILITY IS KEY: Sustainability is as much about the durability of a garment or product as it is about the particular materials. A poorly made merino shirt that lasts a dozen washes before disintegrating is more environmentally damaging than a polyester shirt that persists for a decade.
Obsess more about build quality and craftsmanship than particular fibers. Durability is a top consideration in our gear reviews here, as the best gear is often the most durable. And durable gear that rarely needs replacing is often the most sustainable choice.
CLOSE THE LOOP: Consider what happens at the inevitable end of a garment’s lifespan. Many brands and retailers are taking responsibility for their products by offering refurbishing, reselling, and recycling services. Prioritize gear from companies offering solutions to closing the loop on fiber waste.
LOOK FOR CERTIFICATIONS: Certifications help ensure fibers are sourced transparently, ethically, and sustainably. Certification programs have their own problems, but some are far better than others. Ones to look for are bluesign, the Global Organic Textile Standard, FCS, OEKO-TEX, Cradle to Cradle, Fair Trade, Global Recycled Standard, and Responsible Wool Standard.
KEEP LEARNING: The Textile Exchange is a global non-profit dedicated to driving sustainable innovation in the textile industry. Their Material Change Index is a fantastic tool to learn more about the sustainability of specific fibers used by many of the world’s top outdoor apparel brands.
Ethical Consumer is another excellent resource, with comprehensive data and educational material geared towards holding brands accountable and helping consumers make more sustainable and ethical purchasing choices.
MORE INFORMATION
For more discussion on sustainability and how it relates to the outdoor industry then check out the rest of our Sustainability 101 series:
Or if you are just looking for more information on hiking and backpacking, then be sure to check out some of our other tips and gear reviews:
Or check out our entire Gear Reviews Page, our Knowledge Base Articles, or Destination Guides for more hiking, backpacking, and outdoors related content.
Happy hiking and take care out there in the wild!