By Simon Caterson
NATURE
Clouds: How to Identify Nature’s Most Fleeting Forms
Edward Grahams
Princeton University Press, $49.95
The glare of the city lights prevents most of us from seeing the night sky in its illuminated glory, though in the daytime anyone can look up and behold the epic, evanescent wonder that is the cloudscape. This fascinating book not only identifies types of clouds and explains how they form and disperse, but also reminds us of the close historical connection between art and science in capturing natural phenomena.
While the modern science of meteorology began during the Enlightenment, it was painters who took a lead in the serious appreciation of clouds, not simply including clouds in the picture but also selecting and arranging them to provide directional force as part of the composition of the painting, and thus leading the viewer’s eye through the artwork. Among their many aesthetic properties, clouds are, in atmospheric scientist Edward Graham’s neat phrase, scatterers of light.
Graham’s book includes many examples of the renowned artists who have portrayed clouds in ways that are highly personalised yet true to nature. In his art, Vincent van Gogh famously projected his often-troubled mind onto everything he painted, yet managed to render clouds in ways that correspond to objective categories such as we see in photographs in addition to being the agitated swirls of his Post-Impressionist vision.
In one painting,Wheat Field with Cypresses (1889), Graham discerns “a mixture of mamma, asperitas, hints of fluctus”, suggesting the artist “sees the wind and its turbulent motions”.
Detail from Van Gogh’s 1889 painting, Wheat Field with Cypresses.
Shakespeare referred to clouds as “airy nothings”, and even now, the true nature of clouds remains somewhat elusive. “The reality of the matter,” according to Graham, “is that although we know what a cloud is, there is no precise scientific definition of a cloud. This is because it is impossible to say – with the exact deterministic precision required of science – when a cluster of cloud droplets or ice crystals has become dense enough to constitute the rather nebulous term, ‘cloud’.” The vast majority of clouds appear to simply move across the sky – Graham points out that “most clouds never rain”.
Clouds are immense yet transitory, seemingly weightless yet inevitably falling down due to the force of gravity. They are shapeshifting apparitions that are never exactly the same as any other. “Clouds are always mutating and evolving in the sky,” writes Graham.
Built into the classification scheme stated in the World Meteorological Society’s International Cloud Atlas is a category of clouds that morph from one type to another, known as “mother” clouds. There are five special mother clouds that grow and develop directly because of human activity. A common example is the contrail left by an aeroplane. Another type is constituted by the broken wisps of clouds that form over the forest canopy, especially when conifers are the dominant tree species. There is a special type of cloud that gathers in the vast chasm of Niagara Falls.
Clouds are most broadly classified according to altitude and also divided into species and varieties. We respond to them imaginatively and emotionally – they can appear menacing, yet they can also seem benign or wistful. They can be cotton wool or stainless steel. We see the shapes of humans, animals and objects in clouds such as waves and walls, while other clouds present themselves as random daubs of pure abstraction.
Clouds were once entirely remote from the human world. Increasingly, however, clouds are what we make them in a literal sense as well as imaginatively. “Like it or not,” Graham warns, “we are now the weather makers. The weather extremes that we increasingly experience are direct manifestations of our behaviour and will become more severe as we continue to burn fossil fuels. Mother Nature does not care at all – her role is purely consequential.”
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