WASHINGTON — Cotton Inc. has completed a comprehensive life cycle inventory and life cycle analysis of cotton products designed to establish benchmarks of potential environmental impacts across the global cotton supply chain.
The two-year study, conducted by PE International and part of the Cotton Foundation Vision 21 project, is aimed at helping direct sustainability research efforts for the cotton industry, as well as textile producers and consumer use. The National Cotton Council and Cotton Council International are also key participants in the initiative.
“The textile industry and consumers alike are weary of competition-motivated green marketing,” said Berrye Worsham, president and chief executive officer of Cotton Inc. “This project is about facts and establishing a baseline to measure cotton’s environmental gains moving forward.”
The life cycle of a cotton garment was structured in three phases in the study: fiber production (agricultural processes), fabric production (textile processes) and consumer use (wearing and washing until the end of life.) The life cycle inventory analysis quantified the relevant energy, material inputs and environmental release data through fabric production. The life cycle assessment analysis encompassed fiber production through consumer use and disposal, calculating 1,000 kilograms (or 2,780 golf shirts) and 1,000 kilograms (or 1,764 pairs) of casual pants.
The study found that when the entire cotton life cycle is taken into account, the greatest environmental impact occurs in the consumer use phase, primarily due to laundering. In seven impact categories ranging from water use, ozone depletion, photochemical ozone creation potential, acidification potential and global warming potential, the heaviest impact was in the cut and sew, use and disposal phase associated with 1,000 kilograms of knit and woven fabric.
The next greatest impact on the environment occurred during textile manufacturing, which showed a higher impact than agricultural production in six out of the seven impact categories because of the amount of energy used during yarn spinning and for conditioning, processing and water heating in the fabric preparation and dyeing steps. At the agricultural level, the study revealed the least impact on the environment.
“While agricultural production had the relative lowest impact of the three [lifetime cycle assessment phases], it is still important to examine impacts within this phase and to identify areas for possible improvement,” the study said.
The study revealed that field emissions, associated with fertilizer use, specifically that containing nitrogen, were one of the biggest sources of impact on the environment in the agriculture phase of cotton.
“Once nitrogen is applied to the field it has the potential to be emitted as nitrous oxide, a greenhouse gas with 300 times the impact of carbon dioxide, or it may be leached from the root zone in heavy rains,” the study said.
Among the recommendations made in the study were continuing to conduct research to improve cotton’s water and nitrogen use efficiencies, working with mills to measure additional spinning and wet processing energy demands and water use to help identify opportunities to reduce the impact of textile manufacturing, supporting wastewater reduction research and educating consumers on the benefits of reducing the impacts at the use phase.
The LCI data for fiber production represents a global average of the U.S., China and India, which accounted for 67 percent of the world’s cotton fiber production in 2010, according to the U.S. Department of Agriculture from 2005 through 2009 and is based on regional production weighted averages.
Data on fabric production for knit and woven fabrics, represented as a global average, were collected from representative mills in Turkey, India, China and Latin America, which represented 66 percent of knit and 51 percent of woven world fabric manufacturing in 2009. More than 40 cotton textile companies in China, India, Turkey, Southeast Asia and the Americas were also included in the study.