The Environmental Impact of Cloth versus Disposable Nappies

The environmental impact of cloth nappies compared to disposable nappies, from the Life Cycle Assessment by the University of Queensland in 2009.

This study considered the 'life cycle' impact: from the growing of cotton (for the cloth nappies) and timber (for the wood pulp used in disposables), the manufacture of the nappies and transportation, through to use (including water & energy used in washing cloth nappies) and disposal.

Some interesting information about this study:
  • Kimberly-Clark Australia (manufacturer of Huggies) supplied most of the data regarding disposable nappies.
  • Different average number of nappy changes a day were used to reflect the fact that many people change disposables less frequently than cloth: The study considered low to high impact figures depending on the number of nappy changes. The low impact figure for disposables was 4 changes a day (compared to 5 for cloth) and for high impact - like at the newborn stage - 7 changes a day (cloth was 9).
  • As far as water & energy used in washing cloth nappies, the study included the difference in the total energy used in home washed nappies if you use hot water compared to cold, and a top loader compared to a front loader, and also examined the difference between home washing and using a nappy service.
  • The study considered nappies made of cotton fabric only. Hemp and bamboo fabrics are generally considered more environmentally friendly crops to grow (using less water, pesticides and land space).
  • The researchers included covers (of the plastic pants variety) in their energy/water/waste figures for cloth nappies.
  • The costs for the cloth nappies included energy & fuel transportation costs assuming the cotton would be grown in Australia, transported to Asia for processing and milling into fabric, and shipped back to Australia.
  • Disposable nappies are composed of 40% cellulose (wood pulp), with Australian pine forest plantations the source.
  • Pulp production is responsible for 75% of the non-renewable energy required over the life-cycle of disposable nappies, even though 46% of energy used in pulping is renewable.
  • Home-washed reusable nappies were found to use less non-renewable and total energy over the life cycle than any other nappy system, regardless of the number of nappies used, the mass of nappies, or the type of washing machine.
  • Reusable nappies washed in a top-loading washing machine were found to use more water than disposable nappies or reusable nappies washed in a more efficient front-loading machine.
  • Water resource depletion associated with the softwood production for disposable nappies was higher than for the cotton growing stage of home-washed nappies. This is despite the fact that forestry is typically much less water intensive (on a per-area basis) than cotton growing – indicating that it was the much larger mass of raw material required for the production of disposable nappies over the 2.5 year lifecycle that was the driver for this result.
  • The study assumed that cloth nappies would be soaked in warm water and noted that "heating water for soaking nappies consumes 30-56% of the energy used over the life cycle of home-washed reusables" and that "using solar water heating could substantially reduce the non-renewable resource depletion. More energy is, and hence more greenhouse gas
    emissions generated, if the nappies are tumble-dried or washed in hot water, particularly if a solar hot water system is not used."