As a boy, I kept cacti. A hook-spined Mammillaria, an Opuntia with tufts of small orange spines which became near-invisible once embedded in my delicate fingers, and a few others shared the greenhouse with tomato and cucumber plants and my father’s collection of Streptocarpus. The cacti were sparingly watered in the vain hope that they would flower. I remember my surprise when some cacti seed I had sown sprouted with spineless cotyledons; I think the mould killed them before the wonderful yet monstrous morphologies of the adult plants were revealed. Outside the greenhouse, a lawn grew fast and green, watered by the copious Cumbrian rains.
The rains are conspicuously less copious in Tucson, Arizona. Most of the gardens reflect the desert environment with planting of drought-tolerant plants, magnificent tall saguaro, opuntia, yucca and aloe, set in gravel. But some of the gardens deny their location. Bright green lawns, fertilised and watered, stretched down to the pavement.
Much of the western US is in the grip of a drought, yet in Tucson some people are pouring precious water on grass. These green patches have no obvious utility; they need frequent mowing, weeding and watering. If these people of Tucson are not prepared to adopt more sustainable gardens, which would save them money and inflict no loss of utility, how much harder is it going to be to persuade them to make other changes towards a sustainable lifestyle that will require even a small loss of utility?
Compared with tackling greenhouse gas emissions, tackling wastage of water should be easy. The time scales are short, severe drought may be affecting the south western US within a few months, rather than the multidecadal timescales for the worst of the effects of global warming to become apparent. The problem is local: what the Chinese do in tackling their water shortage problems are irrelevant to the problems in the US and so cannot be used as an excuse to do nothing. There are no feedbacks or complex physics for drought deniers to obfuscate. And some of the solutions are easy: desert gardens or astroturf; or at least not sprinklers on the lawn at noon; covering swimming pools, low water use toilets.
California is also in the grip of drought. In LA sprinklers keep the precious green from turning gold and men hose down the pavement. No hosepipe bans here, no infringement on the personal liberty to fritter away resources, but yet people are happy to, by order of the city council, abandon the sacred right to reverse park.