Diapers.

• Position: LIFE-CYCLE STUDIES

Overview

Humans are the only animals to diaper their young (and not all humans do so), and such an unnatural custom ought to invite more comment--yet the first literary reference to the diaper dates only to the 10th century and it had nothing to do with babies' bottoms. Diapering is a showcase of human ingenuity: the Incas used layers of dried grass in rabbit skin covers, the Inuit sphagnum moss and sealskins. Early Europeans used swaddling strips of tightly cross-woven linen.

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In more recent times, cloth diapers were the norm in developed societies until World War II, when mothers newly entering the workforce began to seek greater convenience. The disposable diaper was launched in 1949 by U.S. housewife-turned-inventor Marion Donovan, who began selling the "Boater" at Saks in New York. Since then, manufacturers in the United States, Europe, and Japan have competed to streamline the bulky garments. Super-absorbent polymers developed by the Japanese company Unicharm revolutionized the modern disposable, sharply reducing leakage and weight. India ranks first in disposable use at 93 billion diapers per year, 20 percent of the global total. The diaper has outgrown babies and is now used by adults suffering from incontinence of varied causes.

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Closing the Loop

An infant needs up to 7,000 diaper changes before leaving diapers behind. This typically requires 36-60 cloth diapers from birth to potty training, adding roughly 14 kilograms of cotton to landfill waste (which should biodegrade within six months). However, use of cloth diapers entails other costs, such as greater water and energy use: perhaps 76,000 liters of water are needed to launder diapers for one infant over two or three years, and each washing-machine load is equivalent to about 35 toilet flushes.

The 450 billion disposable diapers used each year contribute nearly 77 million tons of solid waste to landfills, and a disposable diaper takes at least 500 years to degrade. Because less than 1 percent of the human...