Cotton, a natural, plant-based fiber, is composed primarily of cellulose, a natural polymer and the main ingredient of plant cell walls. Cotton lint is about 95% cellulose, and cellulose contains roughly 44% carbon by mass.1 This carbon is biogenic, meaning it comes from the natural carbon cycle rather than fossil fuels. As a result, cotton apparel act as temporary carbon reservoirs during the use and reuse phases,2 operating within a renewable, closed-loop system.
The Lifecycle of Cotton
The journey begins in the atmosphere, where plants capture CO₂ through photosynthesis. Unlike synthetic fibers such as polyester, which are made from fossil-derived carbon and add new carbon to the atmosphere, cotton cycles existing carbon through renewable storage pathways.2,3
Once in fiber form, that carbon remains stored throughout the product’s entire lifecycle, whether it is being used, reused, or kept for future use.2 In typical apparel, this storage can exist for several years.2 If cotton is converted into long-lived products such as building insulation, carbon storage can extend for decades or longer.2 At any given time, hundreds of millions of tons of atmospheric carbon are temporarily stored in cotton textiles worldwide.2
When composted or used for bioenergy, carbon returns to the biosphere and re-enters the natural carbon cycle, since cotton biodegrades in soil, compost, and aquatic environments. 3,4 Not all materials carry carbon this way. Synthetic fibers, by contrast, resist biodegradation and can persist for decades or centuries, leaving fossil carbon permanently outside the natural cycle4.
Factors that Shape Cotton’s Carbon Impact
Cotton’s ability to store carbon is inherent, but its overall impact depends on how it is grown, used, and managed at end of life.
Farming practices such as cover cropping, reduced tillage, and improved nutrient management can increase soil carbon sequestration and reduce on-farm greenhouse gas emissions.2
Duration of use becomes a key factor in overall impact, because the longer the carbon is stored, the greater the environmental benefit.2 Carbon storage can be extended through product design that emphasizes durability, and end of life pathways, such as recycling and reuse of cotton, continue the cycle and keep carbon out of the atmosphere.2 When recycled, that storage continues in the next product and helps avoid the methane emissions associated with decomposing waste in landfills.² Together, these choices shape how fully cotton's carbon storage potential is realized.
Why Cotton Stands Out
As industries and consumers look for ways to reduce environmental impact, material choice is becoming increasingly important. Cotton offers a renewable, plant-based option that works with natural systems rather than against them.
By storing carbon during use and returning it safely to the biosphere at end of life, cotton represents a different approach to textiles — offering a measurable environmental benefit that sets it apart from synthetic fibers. Sign up for a free account on CottonWorks.com to get access to in-depth sustainability research and strategic insights designed to help your brand meet its net-zero milestones.
- Phillip J. Wakelyn, Noelie R. Bertoniere, Alfred D. French, Devron P. Thibodeaux, Barbara A. Triplett, Marie-Alice Rousselle, Wilton R. Goynes Jr, J. Vincent Edwards, Lawrance Hunter, David D. McAlister, & Gary R. Gamble. (2007). Cotton Fiber Chemistry and Technology (M. Lewin, Ed.; Vol. 17). CRC Press. https://doi.org/10.1201/9781420045888.
- Pires, S. T., Williams, A., Daystar, J., Sagues, W. J., Lan, K., and Venditti, R. A. (2024). “Evaluating cotton apparel with dynamic life cycle assessment: The climate benefits of temporary biogenic carbon storage,” BioResources 19(3), 5074-5095. DOI: 10.15376/biores.19.3.5074-5095.
- Zambrano, M. C., Pawlak, J. J., Daystar, J., Ankeny, M., & Venditti, R. A. (2021). Impact of dyes and finishes on the aquatic biodegradability of cotton textile fibers and microfibers released on laundering clothes: Correlations between enzyme adsorption and activity and biodegradation rates. Marine Pollution Bulletin, 165, 112030. DOI: 10.1016/j.marpolbul.2021.112030
- Li, L., Frey, M., & Browning, K. J. (2010). Biodegradability Study on Cotton and Polyester Fabrics. Journal of Engineered Fibers and Fabrics, 5(4), 42-53). DOI:10.1177/155892501000500406
