You may remember great jubilation in Weather Eye a year or so ago when the 44th IMO Prize was awarded to Jim Dooge. The IMO Prize is meteorology's highest international honour, established by the World Meteorological Organisation in 1955 to commemorate that group's predecessor, the International Meteorological Organisation. Prof Dooge, a long-time member of Seanad Eireann and sometime Irish foreign minister, received the award for his outstanding contribution over the years to hydrology, the science of water - which is, of course, his primary profession. Now the 45th IMO Prize has been presented, and again its recipient is no stranger to this column. Prof Edward Lorenz, an American born in Hartford, Connecticut, and professor emeritus of meteorology at the Massachusetts Institute of Technology, is an atmospheric scientist of world repute, but he became famous to a much wider constituency in the early 1970s when he articulated "chaos theory".
Lorenz's thesis, as applied to meteorology, was that beyond a certain interval of time, the behaviour of the atmosphere becomes inherently unpredictable. No matter how well our computer models reflect its actual behaviour, the initial state of the atmosphere can never be defined accurately enough for them to work effectively for, say, a three-week forecast period. Even the tiniest incidental eddies in the wind-flow may amplify spontaneously over time and in due course achieve proportions sufficient to have a catalytic effect on major weather systems. The atmosphere behaves chaotically.
Chaos theory made it possible to estimate the inherent predictability, or otherwise, of the weather and climate at any given time, and led to significant improvements in the accuracy of the computer models used for weather forecasting. But chaos had applications far beyond the boundaries of meteorology. Lorenz's book, The Essence of Chaos, defined the concept in a way that nonspecialists found relatively easy to understand, and it spawned a whole new glossary of jargon, from "phase spaces" with "sources", "sinks" and "saddles", to "strange attractors", "bifurcations", "tangles" and "period-doubling cascades".
It opened up, in fact, an entirely new field of scientific enquiry, having a profound effect on the thinking of scientists in other disciplines, political decision-makers and the public.
And he coined a phrase. In a lecture in the early 1970s, describing the phenomenon of chaos, Lorenz remarked: "A very small perturbation, in due time, can make things develop quite differently from the way they would have happened if the small disturbance had not been there." Then in a rhetorical question, he went on suggest an image that has become a universal cliche: "Could the flap of a butterfly's wings over Brazil spawn the next tornado up in Texas?"