"It's no longer enough to change our light bulbs. We need to change our culture."

So says Erik Assadourian, senior researcher at the Worldwatch Institute and project director of a provocative and timely new book called 2010 State of the World: Transforming Cultures from Consumerism to Sustainability. Its argument is simple: The most important driver of the world's ecological crises, including climate change, is not venal oil or coal companies or indifferent politicians but western consumer culture -- that is, us.

Global consumption has grown dramatically since World War II, reaching $30.5 trillion in 2006, up sixfold since 1960. This is, in part, a very good thing -- billions of people have emerged from poverty -- but today's prevailing consumption patterns are, quite simply, unsustainable. The rich (meaning you and me) are the worst offenders but ecologists say that even at income levels that we think of as substandard -- say, $5,000 or $6,000 per person per year -- people are consuming at rates that will deplete the earth's resources, cause catastrophic climate change, wipe our species and generally trash the only planet we have. About a third of the world's people live above this standard, and the others, presumably, aspire to do the same.

This is not a message that either business or mainstream environmental groups want you to hear, which is why you don't hear it often. Most businesses, though not all of then, are in the business of persuading people to consume more. They shaped the consumer culture. And enviros have found that telling their members and donors to buy less stuff is a downer, and not an effective fund-raising message, especially among the well-to-do.

But, as Assadourian said during a conference call with reporters, consumer culture is not only causing environmental havoc, it's often failing to deliver the well-being that it promises.

Most people understand -- and psychological studies of happiness confirm -- that after we have achieved basic economic security (itself a cultural norm), what really makes us happy are close relationships, meaningful work, connections to community and good health.

You can't buy those things at the mall.

"Two centuries of intentional cultivation of consumerism has led to us seeing it as perfectly natural to define ourselves primarily by what and how much we  consume," he said. Consumerism is so embedded in our culture today that, most of the time, it's as invisible as the air we breathe.

Here's how Assadourian explained the oft-hidden impact of culture on our lives:

The fact that we see it as normal to be able to identify hundreds of brand logos and jingles, while few of us can identify more than a few species of wild plants and animals -- that's culture.

The fact that we feed our children diets high in sugars, fats, and processed ingredients, even when we know this is making them fat and sick -- that's culture.

The fact that when loved ones die a ritual intended to lay them to rest requires injecting them with toxic chemicals and sealing their bodies up in expensive and ecologically costly caskets -- that's culture.

And the fact that we spend thousands of dollars each year on pets that we now see as part of the family, buying them food, toys, even health care that's better than many people in the world can afford -- that's culture.

It's all true, if mildly depressing. The Independent newspaper quoted one critic who said people need to be persuaded of the benefits of tackling climate change, rather than be presented with a "defeatist and doomsday scenario."

So how do we get from here to where we need to go? "The good news," Assadourian went on, "is that we can replace our consumer culture with a culture of sustainability."