08 December 2016
Going Green All Over
A design for living
by J.R.Thomas
So often we fail to notice the obvious, even when it is right under our feet – or above our heads. Whatever is happening to our climate in the long term (and your correspondent is just old enough to remember the cold winters of the early 1960’s and to have been taught in school geography lessons that the ice age was assuredly returning and that we would all need to move south), it has certainly changed in the last decade. Not to the baking hot extended arid summers we were promised fifteen years ago (computer glitch in the modelling), but to wet summers with severe storms in the autumn, compensated for, if you like that sort of thing, by milder winters.
The latest evidence to demonstrate that all this climatic variation is really happening in the British Isles involves a piece of mind bendingly minutely and painstaking research. Botanists and scientists working for the National Trust for Scotland (oh, yes, as in most things, Scotland has its own) have been conducting research over the last sixty and more years on rare saxifrages growing in Glencoe, previously noted more for a blood curdlingly nasty massacre of the MacDonalds by the Campbells than for the examining of high slopes with microscopes. This peering among the heather is causing scientific concern about the retreat of the rare highland saxifrage (saxifrage rivularis for very serious gardening and botany types) which, the population in Glencoe having been noted in the early 1990’s as about 300 plants – no, not “about”, exactly 300 (scientists do not deal in broad sweeps), is now down to 31. One carelessly placed stag’s foot and it could be 30 by the end of the winter.
Leaving aside the tasteless joke that that the decline mirrors what happened to the Glencoe MacDonalds that freezing night in February 1692, and that they seem to have recovered nicely, this does suggest that something climatic is going on. One presumes that those thorough scientists have discounted heavy footed deer, and indeed heavy footed ramblers, as the cause of the decline, and it is the longer hours of sunshine, or in fact light, (more sunshine in Scotland might take a little believing) that is troubling the tiny bushy plants; but the scientists are certain – producing in supporting evidence that the decline is much greater on south facing slopes, and less on north. And surveys of snow pearlwort, (Sagina Nivalis) on nearby Ben Lawers (cue more vivid imaginings of serious scientists with bottoms in the air and notebooks in hand busy counting) reveals exactly the same behaviour. The plants are retreating up the mountains, on southern slopes disappearing altogether. That tends to rule out the trampling feet possibility, though maybe not careless deer (or picnicking ramblers) sprawling in the sunshine and squashing the rare botanicals.
What is replacing the saxifrage? Grass and rushes. Bad, say the scientists, though no doubt, being experts in saxifrage and sagina, they would say that. The views of botanists who have made life time studies of grass and rushes, might think it all a very good thing – and would no doubt issue a severe reprimand to the Shaw Sheet for lumping all grasses and rushes in one muddled bloc, when they no doubt form many distinct plant varieties. By 2050, say the researchers, (why is it always 2050? what strange significance has that year for forecasters?) many of the rarer Scottish alpine plants will be extinct and the snow line will be on average 21% higher up the highland mountains, with those invasive grasses and rushes seizing yet more territory to which they are not entitled.
So what can the ordinary concerned member of the public do about this? Help is at hand in the perhaps unlikely form of the Arup, the giant civil engineering company. Arup advise on many aspects of design engineering for major urban construction projects around the world. They are, a spokesman said, very concerned about green issues and how to solve the problems of dense urban living. And, he did not say, but it would be reasonable to infer, about growing opposition to large scale inner-city development from those living and working in cities amongst those major construction projects. The firm have commissioned a report to look at the effects of greening cities* which examines how cities may be made more pleasant to live in in the twenty first century; in terms of combatting pollution, but also in the fields of noise – an increasing problem in dense urban living – and in heat intensification. Those of us who live in the UK may not worry much about heat intensification, but even here temperatures in cities are usually noticeably higher than in the rurality outside. Imagine the build-up of temperatures in cities such as Istanbul, Rio de Janeiro, New Orleans. In these cities, and many others, temperatures in the urban core can be up to 12C higher than outside – potentially life threatening to more vulnerable citizens, and certainly making urban sprawl unattractive to live in.
The answer is to green the cities – but not with trees, which take up too much space and are too high maintenance and thirsty. Green roofs are one good solution – which is where our friends the saxifrages might come in, though perhaps not the ones in Glencoe, which would not adapt readily to life in urban Brazil. But green roofs with suitable low maintenance planting can provide remarkable cooling by their insulating qualities to the buildings below, and also, because of their dense vegetation, to the streets around. This is a movement which is catching on fast. Any visitor to a high rise building in Frankfurt or La Defence will be astonished looking down at the growing greenness of those cities from above.
Another and very fashionable solution now catching on, though more so far in warmer locations, is green walls. Babylon, if it ever does get reconstructed, may once again have hanging gardens. Green walls means, in effect, layering walls with planting troughs, automatically watered, planted with robust but preferably lush plants that will coat the parent building with an insulating absorbing layer against pollution, heat, and noise. When mature, the walls will be green waterfalls of planting, many stories high if desired, with little hint of what lies behind. The effect can be to reduce local pollution by up to 20%, and noise levels by a similar amount. It also does a great deal for the well-being of local workers and residents, who seem to be cheered no end by living in a sort of green coated urban jungle.
The message that we need to calm and cool our cities is spreading fast; not so much in the UK (though it surely must in London if the capital is to accept increasing density of use) but in Paris – where new commercial buildings must have either green roofs or solar panels, and in Tokyo, Munich, Zurich, and even Toronto. Green walled buildings can be remarkably attractive and appealing to residential occupiers, who no longer have to poke about in window boxes or cycle off to the allotment to commune with nature. Maybe the losers in this new movement will be modern architects, whose work may be rapidly overgrown in modern versions of Piranesi scenes; perhaps they can retrain as landscape garden designers.
*Cities Alive: Green Building Envelope, published by Arup is downloadable free from their website
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