American homes and their energy consumption account for nearly 40 percent of U.S. emissions, 626 million metric tons of carbon in 2005 alone. But 33 simple actions—ranging from improving the insulation to carpooling—could cut those annual carbon emissions by 123 million metric tons. That savings would more than entirely offset emissions from petroleum refineries, iron and steel works, and aluminum smelters combined.
"We did a careful analysis of the potential to reduce greenhouse gas emissions from changes in energy use by households. We did this by considering not only the hypothetical reduction that would occur if everyone undertook each action but by looking at what is behaviorally realistic," explains ecologist and sociologist Thomas Dietz of Michigan State University, one of the authors of the study laying out the possibilities in this week's Proceedings of the National Academy of Sciences. "A substantial amount of energy use in U.S. households is wasted, and there have been successful programs to eliminate that waste."
Based on this analysis of potential emissions-cutting measures—as well as the success of programs to inspire them—weatherizing homes as well as properly maintaining heating and cooling systems could save more than 37 million metric tons of carbon. Boosting average fuel efficiency in 50 percent of cars from 20.8 miles per gallon to 30.7 mpg—and there are at least 26 vehicles available today that would do that, ranging from compact cars to sport utility vehicles—would save roughly 30 million metric tons. Carpooling, energy-efficient appliances and equipment, and even changing the temperature on washing machines and water heaters also add to the effect. And if 25 percent of drivers went back to driving 55 miles per hour on the highway, nearly eight million metric tons of carbon could be avoided each year by reducing fuel consumption 21 percent.
"People are busy, and when you gasp at your energy bill or at the gas pump you don't know what part of that bill is paying for something you want—like heating, cooling and transportation—and what part of it is just wasted," Dietz says. "We need to make it easier for people to make the links and, for some things, like weatherization, help with the up-front costs."
Similar efforts on a regional scale, such as the Hood River Conservation Project, convinced some 85 percent of possible participants to better weatherproof their homes through a mixture of financial incentives, mass media campaigns and other interventions. And the recent national "cash for clunkers" program for trading in old cars for newer, more efficient vehicles was highly popular "because the money was available up front and not as a tax rebate months later," Dietz says. "The paperwork was done by the dealerships not the car buyers, and it was well publicized by the dealers and, we think, by word of mouth," he adds.
Similar efforts to promote solar power in New Jersey, for example, have largely failed because they involve significant paperwork, delays in collecting financial incentives, and incomplete or hidden information. Similarly, programs to weatherize homes as part of the American Recovery and Reinvestment Act of 2009, better known as the federal stimulus package, may fail because they are not widely known and feature an incentive in the form of a tax credit that could take up to a year to collect. "We have neglected behavioral sciences research on energy since 1980," Dietz notes. "Consumer preferences aren't a given, [or] else there wouldn't be a multibillion dollar advertising industry."
Perhaps the simplest change to make is eliminating so-called "standby" electricity, or the energy needed to run devices, such as televisions, even when they are turned off. The emissions associated with that wasted power amount to an average of more than 94 kilograms of carbon per year for every one of the 111 million households with electricity in the U.S.—more than 10 million metric tons of carbon nationwide every year. A simple power strip that can be flicked off would eliminate all of that.