Tackling greenhouse gas (GHG) emissions is one of the most pressing issues of the 21st century. A key piece of the puzzle is reducing agricultural emissions, and the cotton industry has worked actively over the past several decades to become a net negative contributor through reduced emissions and improved carbon absorption when considering “green” or biogenic carbon in addition to “black” fossil fuel carbon.
Due to cotton’s natural ability to remove carbon from the atmosphere and low production of GHG emissions, cotton has the greatest potential to reduce the climate impacts of the apparel industry out of any of the available fiber types. Carbon dioxide is naturally pulled from the air by cotton plants and is stored in soil and plant material via photosynthesis.
The Road to Net-Zero
Since 1980, the U.S. cotton industry has recorded a 25% reduction in GHG emissions. (Metric is pounds of Co2e per lb. of lint)1 And, in line with the U.N. Sustainable Development Goals,2 the U.S. cotton industry has committed to a science-based target for a further 39% reduction by 2025.3
The improvements in GHG emissions have come from a variety of sources: increased production efficiency; regenerative agriculture and increased soil carbon; the integration of renewable energy; and reduced impact of process inputs such as nitrogen fertilizers.
Historically, the use of nitrogen-based fertilizer is one of cotton production’s major contributors to GHG emissions. Nitrogen is one of the most vital and common ingredients in fertilizers and serves as the main nutrient, or food, the cotton plant needs to grow. Nitrogen use efficiency – how accurately growers are able to tailor nitrogen applications to their crop’s actual needs – has improved immensely for cotton growers over the past decades and is one of the main strategies for reducing GHG emissions. New techniques and technological advancements have helped growers be more efficient with their nitrogen fertilizer use, making sure the plant has exactly what it needs when it needs it and no more. Precision agriculture management is key to lowering nitrogen-based GHG emissions and uses a range of technologies to better measure and predict their crop’s fertilizer needs, including sensors, drones, and sophisticated mapping and measurement tools. These tools and techniques have decreased total fertilizer use per pound of cotton by 14% since 1991.4
The increased adoption of conservation practices similarly reduces the quantity of applied nitrogen fertilizer.5 The potential reductions at a global scale are impressive – reducing nitrogen use in cotton production by 20% would reduce GHG emissions by 2.3 million U.S. tons CO2 equivalent per year; the same 20% reduction would also reduce field emissions associated with nitrogen fertilizer by 3.3 million U.S tons CO2 equivalent per year.6 Together that is equivalent to the GHG emissions avoided by running more than 1,000 wind turbines for a year.7
Renewable Energy for Cotton Processing
Another avenue for GHG reduction is through the switch to renewable energies in cotton processing equipment. Electricity is the primary energy source used to power pumps for irrigating cotton. Using renewable power for irrigation pumps globally would reduce GHG emissions by 2.9 million tonnes of CO2 equivalent per year. Cotton gins that remove the cotton lint from the seed are powered by both thermal and electrical energy. 100% renewable energy use in gins could reduce GHG emissions by 6.2 million U.S. tonnes CO2 equivalent per year.8
Pathways to Progress: Reducing Climate Impacts in Agriculture
GHG: Greenhouse Gases
As we continue to look for ways to make cotton more sustainable, our biggest ally is science. At Cotton Incorporated, we regularly team with leading research institutions to scientifically study how to make cotton more sustainable – either by reducing environmental...
- Field to Market: The Alliance for Sustainable Agriculture. (2021). Environmental Outcomes from On-Farm Agricultural Production in the United States. National Indicators Report, fourth edition. https://fieldtomarket.org/national-indicators-report/
- U.S. Cotton Trust Protocol. (2021). Measures and verifies sustainability commitments. https://trustuscotton.org/about/measures-and-verifies/.
- Cotton Incorporated. (n.d.). Cotton Sustainability Goals. https://www.cottoninc.com/about-cotton/sustainability/cotton-sustainability/.
- USDA NASS Quick Stats Chemical Use Survey data 1991 to 2021. https://quickstats.nass.usda.gov.
- Mullins, G.L., and C.H. Burmester. (1990). Dry Matter, Nitrogen, Phosphorus, and Potassium Accumulation by Four Cotton Varieties. Agronomy Journal 82, no. 4: 729–36. https://doi.org/10.2134/agronj1990.00021962008200040017x.
- Cotton Incorporated. (2017). LCA update of cotton fiber and fabric life cycle inventory, (1). https://cottontoday.cottoninc.com/wp-content/uploads/2019/11/2016-LCA-Full-Report-Update.pdf.
- United States Environmental Protection Agency. (2021). Greenhouse gas equivalencies calculator. https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator
- Cotton Incorporated. (2017). LCA update of cotton fiber and fabric life cycle inventory, (1). https://cottontoday.cottoninc.com/wp-content/uploads/2019/11/2016-LCA-Full-Report-Update.pdf