All human activities impact the environment, especially those activities that consume fossil fuels and water – both of which are coming under increasing pressures. A better question is “Does the production and usage of synthetic fabrics have more negative impact than the available alternatives?” In this case, the answer is clearly “No”.
The history of modern synthetic fibers is relatively short. Synthesized cellulosic fibers such as rayon were developed prior to 1900, but cotton and wool accounted for 90% of all fiber consumption until World War 2 [1]. The development of the first totally synthetic fiber, nylon, was undertaken to find a replacement for silk in parachutes during the Japanese occupation of China. By the end of the war, nylon fibers had been extended into consumer markets.
In quick succession, polyester and other synthetics were developed to respond to demands for fabrics that were strong, lightweight, cheap, and easy to care for. “Wash and wear” became a familiar phrase. The higher consistency of the man-made products was a boon to yarn and fabric producers, allowing higher production speeds with less waste and downtime. More productivity means more efficient in terms of energy and raw materials, hence cheaper.
The synthetic products could be produced in high volumes on a small footprint of space, freeing up agricultural land for food where cotton, sheep, and goats once roamed. The raw materials came from cheap, readily available fossil fuels, and the production processes and byproducts were (mostly) benign. The major byproduct of producing polyester is water. The rapid developments of synthetic fiber technology in the late 20th century displaced cotton and wool as the world’s major fibers. By the end of the century, the world’s six billion people were consuming an average of just under 10 kg of fiber each, and synthetics accounted for more than half of those 55 billion tons per year. Polyester is the most widely-used fiber today, and continues to expand.
While wool production is a fraction of what it once was, cotton has not gone away quietly. Its producers made technical and advertising efforts to remain competitive in the growing global fiber and fabric markets. Technical improvements in agricultural yields, fiber quality, and processing technologies have kept cotton competitive in price and performance, and large advertising campaigns have promoted its “natural” advantages to consumers. As a result, cotton production has also grown, and today claims about one-third of the fibers market vs. wool’s two percent. As a blend material with polyester fibers, poly/cotton fabrics are the mainstay of the global markets for apparel. These blends combine the best of the comfort and performance virtues of each of the fibers.
Cotton’s marketing campaign as a natural fiber gained traction during oil shocks in the 70s, as consumers became aware of the fragility of our imported oil supply, as well as the growing impact on the environment of using (and discarding) items produced from fossil fuels. The campaign was hugely successful, and “polyester” quickly became an euphemism for shiny, tacky, cheap, and unhip. The temporary glut of polyester leisure suits made on high speed knitting machines did not help the image.
The bad image of synthetic fabrics (and the good image of cotton) carries over to the present day, but these images are simplistic. The contribution of synthetic fiber raw materials to world demand for oil is miniscule (about one percent of total petroleum demand) vs. the requirements for gasoline and diesel (about 60% of the total) [2]. It has been calculated that the entire petroleum needs for synthetic fibers could be compensated by a small increase in automobile gas mileage, corresponding to about 5 psi higher air pressure in all vehicle tires.
It is widely known that disposed synthetic fabrics, and especially modern diapers, do not degrade quickly in landfills. But neither does paper – nor carrots – in this oxygen-free environment; landfills are not a good way to dispose of anything. The requirements for repeated washing and drying of cotton diapers costs about as much energy and disposal problems as synthetic ones, so any advantage for reusable diapers is arguable. A plus for synthetics is their potential for being recycled, as is currently done with plastic bottles, to minimize impact on waste streams as well as on raw material needs.
The “good” image of cotton overlooks its terrific demand on fertilizers, pesticides, diesel fuel, and the water needed to meet production and quality requirements [2]. Cotton, by itself, accounts for over 20 percent of the pesticides used on the planet. Additionally, cotton requires chemical treatments (with oil-derived compounds) to make it “permanent press”. Cotton fabrics are no less dependent on petroleum than synthetics, and are significantly more of a drain on water and arable land.
To produce one ton of cotton requires 25,000 tons of water, vs. 360 tons of water for a ton of rayon, or four tons for one ton of polyester. Cotton agriculture currently consumes nearly 350,000 km of agricultural land – about 25 percent of the world’s total. All the world’s rayon and synthetics are produced on less than 50,000 km, primarily on land not usable for food production. Wool production is even more land-intensive than cotton, so is becoming even less viable in a growing world.
Synthetic fibers have become an inescapable part of modern living, and in many areas provide benefits that could not otherwise be had. From bulletproof Kevlar® body armor, to fireproof Nomex® protective suits, to knitted polyester aorta replacements, to high modulus sail fabrics and halyards, to soil-stabilization fabrics for construction sites, to polyester-reinforced radial tires and carbon fiber-reinforced fighter planes, synthetic fiber materials will continue to be needed. There is not enough agricultural land left in the world to meet current demands for apparel fabrics by using only natural fibers, without major impact on food supplies.
There is more work to be done. As petroleum becomes more expensive, alternative sources of raw materials must be found. Plant and bacteria-based materials are currently being studied for their applications to synthetic polymers. Protein-based polymers are of particular interest, because they offer a route to biodegradability and sustainability. This is of particular concern not only for synthetic fabrics, but especially for other plastic materials (food and beverage containers, packaging, toys, etc.) that are finding their way into our oceans, where they break apart and endanger the food chains of birds, fish and – ultimately – people. That is a different and more important topic, for another time.
At the present time there is no reason for an environmentally-conscious consumer to believe that synthetic fabrics are a less desirable choice than “natural” fabrics, especially so for rayon and poly/cotton. Moreover, there will be no going back. Synthetic fabrics will continue to become ever safer, sustainable, and necessary to the economy because there is no other alternative.
[1] http://www.cirfs.org/KeyStatistics/WorldManMadeFibresProduction.aspx
[2] https://www.ifj.com/E-version/toc.asp?ID=34
