Dear EarthTalk: Is it more environmentally friendly to hand-wash dishes or use a dishwasher?
—Jennifer Furnari, Sonora, CA
Dishwashers are the way to go if you comply with two simple criteria. "Run a dishwasher only when it’s full, and don’t rinse your dishes before putting them in the dishwasher." So says John Morril of the American Council for an Energy-Efficient Economy, who also advises not using the dry cycle. The water used in most dishwashers is hot enough, he says, to evaporate quickly if the door is left open after the wash and rinse cycles are complete.
Scientists at the University of Bonn in Germany who studied the issue found that the dishwasher uses only half the energy, one-sixth of the water, and less soap than hand-washing an identical set of dirty dishes. Even the most sparing and careful washers could not beat the modern dishwasher. The study also found that dishwashers excelled in cleanliness over hand washing.
Most dishwashers manufactured since 1994 use seven to 10 gallons of water per cycle, while older machines use eight to 15 gallons. Newer designs have also improved dishwasher efficiency immensely. Hot water can now be heated in the dishwasher itself, not in the household hot water heater, where heat gets lost in transit. Dishwashers also heat only as much water as needed. A standard 24-inch-wide household dishwasher is designed to hold eight place settings, but some newer models will wash the same amount of dishes inside an 18-inch frame, using less water in the process. If you have an older, less-efficient machine, the Council recommends hand washing for the smaller jobs and saving the dishwasher for the dinner party’s aftermath.
New dishwashers that meet strict energy and water-saving efficiency standards can qualify for an Energy Star label from the U.S. Environmental Protection Agency (EPA). Besides being more efficient and getting the dishes cleaner, qualifying newer models will save the average household about $25 per year in energy costs.
Like John Morril, the EPA recommends always running your dishwasher with a full load and avoiding the inefficient heat-dry, rinse-hold and pre-rinse features found on many recent models. Most of the appliance’s energy used goes to heat the water, and most models use just as much water for smaller loads as for larger ones. And propping the door open after the final rinse is quite adequate for drying the dishes when the washing is done.
CONTACTS: American Council for an Energy Efficient Economy, (www.aceee.org/consumerguide/topdish.htm); Energy Star, (www.energystar.gov/index.cfm?c=dishwash.pr_dishwashers).
Dear EarthTalk: Someone told me that methane gas emitted by cows is a major contributor to global warming. I thought it was a joke, but is this true?
—David Rietz, Goose Creek, SC
Accumulation of methane in the Earth’s atmosphere has nearly doubled around the globe over the past 200 years. Scientists believe that rising concentrations of this "greenhouse gas," which absorbs and sends infrared radiation to the Earth, are causing changes in the climate and contributing to global warming.
Livestock animals naturally produce methane as part of their digestive process, belching it while chewing cud and excreting it in their waste. According to the Worldwatch Institute, about 15 to 20 percent of global methane emissions come from livestock. John Robbins, author of The Food Revolution and Diet for a New America, says that methane is 24 times more potent a greenhouse gas than carbon dioxide, the culprit normally at the center of global warming discussions.
And there are plenty of sources of it: The United States Department of Agriculture (USDA) reports that animals in the U.S. meat industry produce 61 million tons of waste each year, which is 130 times the volume of human waste produced, or five tons for every U.S. citizen. In addition to its impact on climate, hog, chicken and cow waste has polluted some 35,000 miles of rivers in 22 states and contaminated groundwater in 17 states, according to the U.S. Environmental Protection Agency.
Ronnie Cummins, national director of the Organic Consumers Association, says that a food chain with meat at its top is unsustainable not only as a major contributor of greenhouse gases, but also with regard to inefficient dedication of large amounts of acreage to livestock grazing. The USDA, for example, says that growing the crops necessary to feed farmed animals requires nearly 80 percent of America’s agricultural land and half of its water supply.
In addition, animals raised for food in the U.S. consume 90 percent of the country’s soy crop, 80 percent of its corn crop, and 70 percent of its grain. "If all the grain currently fed to livestock in the United States were consumed directly by people, the number of people who could be fed would be nearly 800 million," says Cornell ecologist David Pimentel. He adds that irresponsible livestock farming is directly or indirectly responsible for much of the soil erosion in the U.S.
Unfortunately, environmental problems associated with livestock rearing are not limited to the United States. According to the international environmental journal, Earth Times, meat production grew more than fivefold worldwide during the latter half of the 20th century. And as intensive "factory" farming methods of raising livestock spread from the U.S. to other countries—many with regulatory monitoring and enforcement standards far worse than our own—this form of pollution is sure to play an increasingly larger role in environmental problems moving forward.