Threshold and pattern dynamics may allow everything from earthquakes, drougths and even epidemics to be predicted
Credit: AFP
Since the first augur peered into a sheep's entrails or the alchemist his crystal ball, humans have been searching for a reliable way to divine the future. In the 21st century the quest has been taken up by science.
In the case of major natural events like earthquakes, volcanic eruptions, violent floods, disease epidemics, tsunami, drought and soil erosion, failure to predict the future can mean death, suffering and loss for thousands.
These events are hard to study because they occur over long time scales, in hidden places and in sudden, erratic episodes. But they all have telltale buildup signs which, correctly interpreted, can help us to zero in on the timing and scale of the impending event – and provide those who might be affected with early warning, says ‘Siva' Sivapalan of the University of Western Australia in Perth.
This exciting new field of science is known as 'threshold and pattern dynamics', because it involves understanding when a vital threshold (to a catastrophe or major change) is crossed - and recognising patterns in the things that are driving it. Australian and international scientists met in Perth, Western Australia recently at a Sir Mark Oliphant Conference on the Frontiers of Science, to compare notes and polish their latest high-tech ‘crystal balls'.
There are thresholds in human affairs too – booms and crashes in the money markets, sudden shifts in public opinion, changes in community behaviour, the explosion in the World Wide Web, even the outbreak of wars.
Threshold and pattern dynamics uses mathematics and computers to build a model of the factors driving uncommon and important events, Sivapalan explains. "By running these models forward in time, it becomes possible to predict when vital thresholds will be crossed – when things will shift dramatically from their present state to another, possibly dangerous or unstable one.
"For example, if you think about rain falling on the soil, it reaches a point where the soil has absorbed as much water as it can, a threshold is crossed, and the water begins to run off and cause flooding," he says. "Another example of a threshold is erosion, when the power of the wind or floodwater reaches a point where it can dislodge soil particles and sweep them away. A third case is when an apparently stable environment like farmland is hit by rising saline groundwater – and everything suddenly dies."
Some thresholds are reversible, others are not – or are extremely hard to re-cross, according to Sivapalan. Hence the importance of having good predictive tools. "The build-up to many of these things is extremely hard to observe, perhaps because it takes place somewhere it is not easy to take measurements. Then the challenge is to identify telltale things we can observe, and see if we can identify patterns in them which point to a future threshold being crossed."
The task, which scientists around the world are working on, is immensely complex and challenging, but in fields like earthquake prediction, there are encouraging signs of progress.
The science of threshold and pattern dynamics has its roots in the efforts of scientists over the last 20 years to predict earthquakes. Geologists can measure the build-up of giant stresses along critical rock fractures (or faults) deep in the Earth, and estimate the accumulated energy – but knowing exactly when the rocks will slip and how much energy will be released has proven a huge challenge.
A team led by John Rundle at the University of California in Davis has developed computer-based methods that forecast earthquakes with much greater precision. "Most people would say that earthquakes can't be predicted or forecast and, indeed, there have been many notable failures," he says. However, his team has overcome the main obstacle to prediction: time. Humans live for a few decades, but large quakes recur over hundreds of years – outside our ability to accurately observe and remember.
Futuroception
It's always interesting to discuss whether everything is happening due to a terribly complicated game of cause and effect or whether the future is fundamentally unpredictable. I think this might be an unanswerable question. However, in the book 'Futuroception' Peter Lemans tries to give an answer and introduces futuroception as a common human sense. I would like to discuss his conclusions with other people, who have read the book.
Wayne