A question of extremes

Watching Storm Sandy bring New York to a halt carried echoes of Thunder Thursday in Newcastle: the irresistible raw power, tower blocks left as blacked out stumps, cars wedged into flooded underpass caverns as if by a child wrecking their toys. An extreme event, even by the USA’s practised hyperbole. Trouble is trying to define what an extreme event is. Not a priority in the desperate hours of the storm or the drawn out agony of the clear up but important eventually because climate predictions suggest more extremes and we need to know how to recognise shifting patterns in the weather that may result. The British Ecological Society, the UK’s learned body for ecologists, has set out to crystallise what we know about extreme events and their impact on freshwater habitats. Lakes, rivers and ponds all depend on water, how much of it and the quality, but these vary naturally. All these habitats develop as an interplay of landscape with climate, the changing seasons and occasional unusually high rainfall or prolonged dry spell. These ups and downs are important, creating new habitat and rejuvenating the old. Humans are very good at taming natural changes, for the understandable reason that we do not want to be flooded or have our crops fail for want of water. We are good at engineering out the everyday rhythms  of nature. A genuine extreme is much harder to define: something that is both remarkable in amount or duration or timing but also that has a demonstrable effect, resetting the ecological stage. Storm Sandy certainly fits the first criteria and for many people in Newcastle, Morpeth and any of the other flood-struck neighbourhoods I suspect the storms have altered their world irrevocably. The stickies above capture part of the British Ecological Society’s concern, especially at “double whammies” as multiple problems pile up: droughts and floods, habitats fragmenting and climate shifting. Working on a large enough scale across whole landscapes is one approach to resist extremes. We cannot put a giant dome over the whole of the Bay to protect it. Instead give nature room for manoeuvre, refuges to hunker down and space to change.