To cut energy use, save money and, while you’re at it, live a greener life, you can turn down the air conditioning, back off the accelerator, hop on a bike.

But when it comes to your personal energy tally, there’s another big but not as commonly considered source: the stuff you buy. Every product, from televisions to teapots, takes energy to get to the shopping bag – energy to mine raw materials, make the product and ship it.

Yet that use goes unreported in the tracking of greenhouse gases and energy. Though some states may be trying to stabilize warming emissions, worldwide emissions driven by the consumption of U.S. residents and businesses actually are going up.

“From the perspective of John Q. Public, who’s wondering, “What can I do to reduce emissions?’ saying certain activities count and others don’t doesn’t pass the laugh test,” said David Allaway, the point man for waste and consumption issues at Oregon’s Department of Environmental Quality. “And we need credibility with the public on this issue.”

Downplaying consumption-related emissions in the U.S. greenhouse gas count is understandable, Allaway says. The numbers are tough to pin down. No state is formally tracking it. Neither is the nation.

At the same time, a pending U.S. Environmental Protection Agency study estimates half of U.S. global warming emissions are tied to material and food consumption.

Researchers say the national greenhouse gas count could jump by as much as 30 percent if the energy used to make rising U.S. imports – typically from countries such as China, where less efficient industries use dirtier energy sources -was taken into account.

Consumers think about the electricity a product uses after they buy it. But that doesn’t account for the energy used making the thing.

Depending on the product, that can be a big deal. One example: A 2005 study by Lawrence Berkeley National Laboratory concluded that 58 percent of a personal computer’s emissions occur before a customer buys it.

Allaway is leading his state’s effort to encourage less waste production. The program encourages consumers to buy used instead of new, durable instead of cheap. It nudges businesses to use fewer materials, reduce packaging and make products easier to repair, reuse and recycle.

Some help is coming from the popular culture. The hit movie “Wall-E” opens with a robot alone (except for a cockroach) on an Earth devastated by rampant consumption.

The subject also is getting more scrutiny in Western Europe, where consumption is about a third less than U.S. levels.

In the United Kingdom, a government-financed study recently concluded that U.K. emissions, reported to have dropped by 5 percent from 1992 to 2004, actually rose when the greenhouse gases from imports were taken into account. U.K. supermarket chain Tesco recently stuck “carbon labels,” a carbon price tag of sorts, on 20 products.

Stateside, the Maryland-based Center for the New American Dream started its “carbon-conscious consumer” campaign last summer, emphasizing such things as breaking “the bottled water habit.” In September, Wal-Mart began asking suppliers to measure their carbon footprint and find ways to reduce it.

Environmental groups are pushing to make “sustainable consumption” as trendy as eating local and swapping canvas bags for plastic. The Sierra Club points to the consumption-fueled damage done, including decreases in forest cover and fisheries, and frets about the consequences if developing countries strive for U.S. standards of living.

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