If you're curious about the US position on environmentalism, you could drop in at the Angel's Nest Retreat in Taos, New Mexico - a refuge-cum-conference centre for stressed-out New Agers. There, in what describes itself as a "sustainable exotic paradise", you may not only "dance to the rhythm of your soul", achieve rejuvenation in a floating angel pod and enjoy the healing rays of a photonic, probiotic light machine - you can also, when the rhythm stutters, take off into the wilderness in your Hummer.
Britain has yet to embrace the Hummer, although we are growing worryingly keen on its cousin, the four-wheel-drive sports utility vehicle, or SUV. But if the SUV is a juvenile delinquent, browbeating its way through congested urban traffic or tearing up green lanes in the name of off-road recreation, the Hummer is a hardened heavy - a six-litre, four-tonne, £40,000-plus freak of a vehicle, notorious for its profligacy with petrol (less than five miles to the gallon off-road). It has also become a symbol for much of what is wrong with the US, from gun-toting backwoods- ishness to the complacent parochialism of the Bush heartlands. Stuff global warming, and while you're at it, stuff the rest of the world, the Hummer proclaims. Carbon-emissions cuts are for wimps.
Even in the US, where SUV ownership is rising fast, this doesn't go down well, which is why a low-intensity war is in progress between groups such as the Earth Liberation Front and those who own or sell the hated machines. Recent tactics have included spray-painting the offending vehicles with slogans such as "Fat, lazy Americans". As John Kerry found recently, any politician who claims environmental credentials but also uses a gas-guzzling SUV needs to tread very carefully when he enters the fray.
And such a man, somewhat counter-intuitively, is Arnold Schwarzenegger, novice governor of California, self-styled greenie and owner of no fewer than seven Hummers. Schwarzenegger's powers of persuasion are legendary, but how could the owner of seven such monsters reconcile this with environmentalism?
Simple. You green the Hummer.
Thanks in part to Schwarzenegger, the quest for the green Hummer has taken on Grail-like proportions. The ones at Angel's Nest Retreat run on vegetable oil and could also use hydrogen or natural gas. Others talk of fuel cells, ethanol, batteries. The governor himself last year launched a "hydrogen highways" programme, vowing to make California the test bed for a new age of zero emissions, and inviting bids from manufacturers to convert one of his Hummers to carbon-free operation. General Motors got the contract, only to withdraw, citing "prohibitive" difficulties. Local inventors, including one rejoicing in the company name of Intergalactic Hydrogen, have since picked up the baton.
Can it be done? Technically, yes - the Angel's Nest veggie-Hummer is testimony to that. Should it be done? In environmental terms, almost certainly not - it flies in the face of energy efficiency. So why do it? "The green Hummer makes a point that no other car can make," Schwarzenegger's director of clean-air policy said last month. If green technology works on a Hummer, he explained, it will work on any other car.
There is, however, an alternative message - which is that, for all the polls pointing to Americans' concern for the environment, many of them, even the best-intentioned, still can't get their heads, or their hearts, round the changes needed.