The 40th anniversary of Earth Day arrives this week to relatively little fanfare. We’re focused on other things: high unemployment, a moribund economy, residual sniveling over health insurance reform. But 40 years is an important milestone.

I was the Earth Day coordinator at my junior high school in Wayne, Pennsylvania, 40 years ago. I remember running off Earth Day flyers on the school’s mimeograph machine and can still recall that sweet (no-doubt-toxic) aroma of the chemicals those machines used. I recall, too, the huge celebration in Philadelphia’s Fairmount Park (I believe the largest Earth Day celebration anywhere that year). Pioneering landscape architect Ian McHarg, of the University of Pennsylvania, chaired the event.

One of my distinct memories was of a speaker asking participants to pledge never to buy a new internal-combustion-engine car. We knew about the air pollution and resource extraction impacts of petroleum (though not yet global warming), and automobiles were correctly recognized as one of the major culprits. I didn’t join that pledge—suspecting, rightly, that I would indeed buy a new car somewhere along the line, and I’ve bought several. But all of us, cheering the speakers from the broad expanse of lawn at Fairmount Park that day, knew that reducing our addiction to oil was important.

Unfortunately, our enthusiasm didn’t get us very far.

By the time the first Earth Day came along in 1970, the world had consumed roughly 240 billion barrels of oil since the dawn of the petroleum age (when oil was discovered in 1859 in Titusville, Pennsylvania). Today, in 2010, that cumulative consumption is up another 860 billion barrels — to 1.1 trillion barrels. That’s right, of all of the oil consumed in the world since the dawn of the petroleum age, an astonishing 78% of it has been consumed since Earth Day in 1970 — that day when environmental awareness reached the mainstream! [Early data from “The Oil Age: World Oil Production 1859 – 2050″; later data from the BP Statistical Review of World Energy, June 2009.]

Three years after the first Earth Day, in 1973, the world was hit with the “energy crisis,” and then a second one at the end of the 1970s. This was another incentive to conserve — but still our petroleum consumption climbed. And, in the process, we’ve released all of that stored carbon — carbon that took hundreds of millions of years to accumulate — into the atmosphere, contributing to global climate change.

We can’t go another 40 years without dramatic reductions in oil consumption. Indeed, most experts say we can’t go even another 20 years on our present course. We’re long past the time for serious action on our addiction to fossil fuels. While I didn’t pledge to never buy a new car 40 years ago, I did make a personal commitment to doing what I could to make a difference. The company I founded in 1985 — 15 years after that first Earth Day — BuildingGreen, LLC, is one of the ways I’ve tried to make a difference — publishing information on reducing the environmental impacts of buildings and the built environment.

Clearly, there’s a lot left to accomplish, but I remain guardedly optimistic that once our nation really gets it, we will be able to employ the sort of focused determination and drive shown in the retooling of our entire industrial sector during World War II while Americans accepted dramatic reductions in personal resource consumption necessary to divert resources to the war effort. With the growing solar and wind industries, with know-how in weatherizing and insulating existing buildings, with new models about how to create pedestrian-friendly communities, and with the best universities in the world pushing the technology innovation, we have the potential to solve these challenges once our nation collectively decides it’s finally time to take action.

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Alex Wilson is the executive editor of Environmental Building News and founder of BuildingGreen, LLC. To keep up with his latest articles and musings, you can sign up for his Twitter feeds.