HERE’S one popular vision for saving the planet: Roll out from under the sumptuous hemp-fiber sheets on your bed in the morning and pull on a pair of $245 organic cotton Levi’s and an Armani biodegradable knit shirt.

Stroll from the bedroom in your eco-McMansion, with its photovoltaic solar panels, into the kitchen remodeled with reclaimed lumber. Enter the three-car garage lighted by energy-sipping fluorescent bulbs and slip behind the wheel of your $104,000 Lexus hybrid.

Drive to the airport, where you settle in for an 8,000-mile flight— careful to buy carbon offsets beforehand — and spend a week driving golf balls made from compacted fish food at an eco-resort in the Maldives.

That vision of an eco-sensitive life as a series of choices about what to buy appeals to millions of consumers and arguably defines the current environmental movement as equal parts concern for the earth and for making a stylish statement.

Some 35 million Americans regularly buy products that claim to be earth-friendly, according to one report, everything from organic beeswax lipstick from the west Zambian rain forest to Toyota Priuses. With baby steps, more and more shoppers browse among the 60,000 products available under Home Depot’s new Eco Options program.

Such choices are rendered fashionable as celebrities worried about global warming appear on the cover of Vanity Fair’s “green issue,” and pop stars like Kelly Clarkson and Lenny Kravitz prepare to be headline acts on July 7 at the Live Earth concerts at sites around the world.

Consumers have embraced living green, and for the most part the mainstream green movement has embraced green consumerism. But even at this moment of high visibility and impact for environmental activists, a splinter wing of the movement has begun to critique what it sometimes calls “light greens.”

Critics question the notion that we can avert global warming by buying so-called earth-friendly products, from clothing and cars to homes and vacations, when the cumulative effect of our consumption remains enormous and hazardous.

“There is a very common mind-set right now which holds that all that we’re going to need to do to avert the large-scale planetary catastrophes upon us is make slightly different shopping decisions,” said Alex Steffen, the executive editor of Worldchanging.com, a Web site devoted to sustainability issues.

The genuine solution, he and other critics say, is to significantly reduce one’s consumption of goods and resources. It’s not enough to build a vacation home of recycled lumber; the real way to reduce one’s carbon footprint is to only own one home.

Buying a hybrid car won’t help if it’s the aforementioned Lexus, the luxury LS 600h L model, which gets 22 miles to the gallon on the highway; the Toyota Yaris ($11,000) gets 40 highway miles a gallon with a standard gasoline engine.

It’s as though the millions of people whom environmentalists have successfully prodded to be concerned about climate change are experiencing a SnackWell’s moment: confronted with a box of fat-free devil’s food chocolate cookies, which seem deliciously guilt-free, they consume the entire box, avoiding any fats but loading up on calories.

The issue of green shopping is highlighting a division in the environmental movement: “the old-school environmentalism of self-abnegation versus this camp of buying your way into heaven,” said Chip Giller, the founder of Grist.org, an online environmental blog that claims a monthly readership of 800,000. “Over even the last couple of months, there is more concern growing within the traditional camp about the Cosmo-izing of the green movement — ‘55 great ways to look eco-sexy,’ ” he said. “Among traditional greens, there is concern that too much of the population thinks there’s an easy way out.”

The criticisms have appeared quietly in some environmental publications and on the Web.

GEORGE BLACK, an editor and a columnist at OnEarth, a quarterly journal of the Natural Resources Defense Council, recently summed up the explosion of high-style green consumer items and articles of the sort that proclaim “green is the new black,” that is, a fashion trend, as “eco-narcissism.”

Paul Hawken, an author and longtime environmental activist, said the current boom in earth-friendly products offers a false promise. “Green consumerism is an oxymoronic phrase,” he said. He blamed the news media and marketers for turning environmentalism into fashion and distracting from serious issues.

“We turn toward the consumption part because that’s where the money is,” Mr. Hawken said. “We tend not to look at the ‘less’ part. So you get these anomalies like 10,000-foot ‘green’ homes being built by a hedge fund manager in Aspen. Or ‘green’ fashion shows. Fashion is the deliberate inculcation of obsolescence.”

He added: “The fruit at Whole Foods in winter, flown in from Chile on a 747 — it’s a complete joke. The idea that we should have raspberries in January, it doesn’t matter if they’re organic. It’s diabolically stupid.”

Environmentalists say some products marketed as green may pump more carbon into the atmosphere than choosing something more modest, or simply nothing at all. Along those lines, a company called PlayEngine sells a 19-inch widescreen L.C.D. set whose “sustainable bamboo” case is represented as an earth-friendly alternative to plastic.

But it may be better to keep your old cathode-tube set instead, according to “The Live Earth Global Warming Survival Handbook,” because older sets use less power than plasma or L.C.D. screens. (Televisions account for about 4 percent of energy consumption in the United States, the handbook says.)

“The assumption that by buying anything, whether green or not, we’re solving the problem is a misperception,” said Michael Ableman, an environmental author and long-time organic farmer. “Consuming is a significant part of the problem to begin with. Maybe the solution is instead of buying five pairs of organic cotton jeans, buy one pair of regular jeans instead.”

For the most part, the critiques of green consumption have come from individual activists, not from mainstream environmental groups like the Sierra Club, Greenpeace and the Rainforest Action Network. The latest issue of Sierra, the magazine of the Sierra Club, has articles hailing an “ecofriendly mall” featuring sustainable clothing (under development in Chicago) and credit cards that rack up carbon offsets for every purchase, as well as sustainably-harvested caviar and the celebrity-friendly Tango electric sports car (a top-of-the-line model is $108,000).

One reason mainstream groups may be wary of criticizing Americans’ consumption is that before the latest era of green chic, these large organizations endured years in which their warnings about climate change were scarcely heard.

Much of the public had turned away from the Carter-era environmental message of sacrifice, which included turning down the thermostat, driving smaller cars and carrying a cloth “Save-a-Tree” tote to the supermarket.

Now that environmentalism is high profile, thanks in part to the success of “An Inconvenient Truth,” the 2006 documentary featuring Al Gore, mainstream greens, for the most part, say that buying products promoted as eco-friendly is a good first step.

“After you buy the compact fluorescent bulbs,” said Michael Brune, the executive director of the Rainforest Action Network, “you can move on to greater goals like banding together politically to shut down coal-fired power plants.”

John Passacantando, the executive director of Greenpeace USA, argued that green consumerism has been a way for Wal-Mart shoppers to get over the old stereotypes of environmentalists as “tree-hugging hippies” and contribute in their own way.

This is crucial, he said, given the widespread nature of the global warming challenge. “You need Wal-Mart and Joe Six-Pack and mayors and taxi drivers," he said. “You need participation on a wide front.”

It is not just ecology activists with one foot in the 1970s, though, who have taken issue with the consumerist personality of the “light green” movement. Anti-consumerist fervor burns hotly among some activists who came of age under the influence of noisy, disruptive anti-globalization protests.

Last year, a San Francisco group called the Compact made headlines with a vow to live the entire year without buying anything but bare essentials like medicine and food. A year in, the original 10 “mostly” made it, said Rachel Kesel, 26, a founder. The movement claims some 8,300 adherents throughout the country and in places as distant as Singapore and Iceland.

“The more that I’m engaged in this, the more annoyed I get with things like ‘shop against climate change’ and these kind of attitudes,” said Ms. Kesel, who continues her shopping strike and counts a new pair of running shoes — she’s a dog-walker by trade — as among her limited purchases in 18 months.

“It’s hysterical,” she said. “You’re telling people to consume more in order to reduce impact.”

For some, the very debate over how much difference they should try to make in their own lives is a distraction. They despair of individual consumers being responsible for saving the earth from climate change and want to see action from political leaders around the world.

INDIVIDUAL consumers may choose more fuel-efficient cars, but a far greater effect may be felt when fuel-efficiency standards are raised for all of the industry , as the Senate voted to do on June 21, the first significant rise in mileage standards in more than two decades.

“A legitimate beef that people have with green consumerism is, at end of the day, the things causing climate change are more caused by politics and the economy than individual behavior,” said Michel Gelobter, a former professor of environmental policy at Rutgers who is now president of Redefining Progress, a nonprofit policy group that promotes sustainable living.

“A lot of what we need to do doesn’t have to do with what you put in your shopping basket,” he said. “It has to do with mass transit, housing density. It has to do with the war and subsidies for the coal and fossil fuel industry.”

In fact, those light-green environmentalists who chose not to lecture about sacrifice and promote the trendiness of eco-sensitive products may be on to something.

Michael Shellenberger, a partner at American Environics, a market research firm in Oakland, Calif., said that his company ran a series of focus groups in April for the environmental group Earthjustice, and was surprised by the results.

People considered their trip down the Eco Options aisles at Home Depot a beginning, not an end point.

“We didn’t find that people felt that their consumption gave them a pass, so to speak,” Mr. Shellenberger said. “They knew what they were doing wasn’t going to deal with the problems, and these little consumer things won’t add up. But they do it as a practice of mindfulness. They didn’t see it as antithetical to political action. Folks who were engaged in these green practices were actually becoming more committed to more transformative political action on global warming.”