A vacation is such a wonderful chance to seek out the unusual and inexplicable. This month my family and I are immersed in a foreign culture, intrigued and perplexed by the ways of an alien people. Most confounding, this culture is my own.

While much of the industrialized world has begun efforts to rein in emissions of greenhouse gases in order to mitigate global warming and the resulting climate change, my home country, the United States, remains in blissful denial. Otherwise intelligent and educated Americans are blithely embracing lifestyles that spew out record levels of carbon dioxide.

According to “Vital Signs 2000,” published by the Worldwatch Institute (Washington, D.C.), over the past 10 years carbon emissions have increased 10.3 percent in the U.S. During the same period, European Union carbon emissions have dropped 0.7 percent, primarily due to emissions cuts in Germany and the U.K.

In Japan, emissions rose 5.6 percent over the past decade, according to Worldwatch. Nevertheless, Japan’s “carbon intensity,” or emissions per unit of economic output, is the lowest in the world, and remained steady between 1990 and 1996.

Of course I’m not surprised to find my fellow Americans wrapped in a self-congratulatory cloak of confidence. U.S. military forces roam the skies and seas unchallenged, and the U.S. economy has been robust for so long that an entire generation believes recessions are economic dinosaurs.

Even the generations that should know better have embraced today’s bumper-sticker thinking: Shop till you drop; spending shall set you free; there’s no problem money can’t solve.

Despite unusual and severe weather patterns worldwide that continue to underscore increasing climate change, American consumers continue to shop for bigger, thirstier vehicles. Giddy on record-breaking profits, car company executives are scrambling to feed the conspicuous consumption of Americans, while ignoring trends toward fuel efficiency that have become inevitable common sense elsewhere.

Sports utility vehicles are still all the rage here and, incredibly, getting larger. SUV passenger trucks can seat up to eight or more adults in roomy comfort, plus haul enough camping and outdoor equipment for a scout troop.

Few SUVs ever see a dirt road, however, much less wilderness terrain. Most are being driven by white-collar executives and suburban parents who come closest to the great outdoors when they visit L.L. Bean outlet stores. And just so that even the most uninformed moms and dads will not mistake these family tanks for real work vehicles, the largest SUV made by automaker GM is called a Suburban.

Suburbans weigh more than 2.5 tons, seat nine people, are more than 190 cm tall, 2 meters wide, and more than 5.5 meters long, and get 6.7 km per liter of gasoline on the highway. In comparison, a GM Saturn sedan seats five adults, weighs 1.2 tons, is 140 cm tall, 168 cm wide, 4.5 meters long, and gets 15.2 km per liter on the highway. The latter costs $14,000, the former $40,000.

In their irrational exuberance, however, Americans are no longer satisfied with really big gas guzzlers. Now it seems there is a market for HUGE gas guzzlers. So, thanks to GM, the master of the main street moose, please welcome the Hummer.

In a New York Times article (Aug. 6), headlined “GM has high hopes for vehicle truly meant for road warriors,” reporter Keith Brasher explains: “Trying to capture the spirit of the times, General Motors occasionally introduces a whole new brand. . . . Its latest venture: the Hummer.”

For those unfamiliar with the Hummer, imagine a tank on wheels. The Hummer looks a bit like a Jeep, but much longer, and a good bit wider.

According to Brasher, “the Hummer started as a military transport, the Humvee, which was used in the Persian Gulf War for everything from launching missiles to ferrying the wounded.”

GM recently purchased the Hummer brand, and while continuing to sell the current model it will also introduce several smaller versions of the military vehicle.

The new Hummers will be only 4.5 meters long (Suburbans are 5.5), but will weigh 3.5 tons, a ton more than Suburbans, and be 30 cm wider. Any thought that Hummers could be practical transportation disappears with a look inside. While a Suburban can seat nine, Hummers will seat only four.

The Hummer will get 6.3 km per liter on the highway, 5.5 in the city. If this seems high for such a monolith, it is. Brasher reports that the Hummer will only manage this mileage because it has weak acceleration and burns diesel fuel. Diesel gives 35 percent better mileage than gasoline.

Hummers are also dirty. They emit far more air pollutants than cars, according to Brasher, since under U.S. federal regulations large sport utilities are allowed to emit 5.5 times the nitrogen oxides of cars. Nitrogen oxides are greenhouse gases that contribute to global warming and cause smog.

Since all this impracticality comes at a steep price anyway — $93,000, to be exact — one might assume that Hummer lovers would pay even a bit more to get a hold of one of these babies. With this in mind, the least GM could do is put cleaner engines on its Hummers, pass the cost along to buyers and still sell just as many vehicles.

But what is environmental common sense elsewhere is not at GM. Brasher points out that while Ford has improved its SUVs and pickups so they do not pollute any more than cars, “GM does not plan to reduce air pollution from its Hummers and other large sport utility vehicles until required to do so by federal regulations in 2004.”

Such blatant disregard for the environment is corporate irresponsibility in the extreme, particularly within an industry that is already to blame for much of the carbon emissions that have spawned climate change.

Then again, what does one expect from a company that hopes to put 150,000 Hummers on the road annually? Certainly not responsible corporate citizenship.