Predicting natural events
Box 2 | Avoiding a climate crash
Although the climate appears to be changing slowly, the climate has changed quite rapidly in the past. Abrupt climate change is an example of a threshold phenomenon. Scientists are looking at evidence of abrupt climate change in the past to understand present climate change. They ask questions such as: Are there thresholds? What drives the thresholds? Can crucial patterns and interactions be identified? and How will things be different if we cross the threshold? to get some idea of how likely rapid climate change is in the near future. If these questions can be answered, we might be able to figure out how close we are to the threshold and determine the probability of tipping our climate into a different state.
Atmospheric researchers at the CSIRO are analysing past abrupt climate changes to try and identify the external forces that might cause our present climate patterns and ecosystems to collapse.
An example is the drought which has lately afflicted eastern Australia. The subtle difference from past dry periods is the interaction between drought and warming. While this drought is similar to past events in its lack of rainfall, a new feature this time is heat. It is by far the hottest drought on record. This combination is pushing many parts of the landscape, including deep-rooted trees, beyond the threshold of no return.
By identifying the external forces that drive such events, it may be possible to predict critical changes and either prevent them, or else manage the consequences better.
The researchers analyse well-understood systems – like fires and stock markets – to understand the drivers behind climate change. This approach has revealed hallmarks common to other complex systems which indicate there may be universal factors that can be used to analyse all systems.
This research opens the way to better manage human actions that do the greatest damage to the environment and natural ecosystems. It means that we are not completely powerless to influence the trajectory of anthropogenic climate change, provided we are capable of a truly global response to a global challenge.
Box
Box 1. Defining thresholds
Related sites
Abrupt climate change: Facts and fiction
Predictions of accelerated climate change
(Met Office, UK)
Coupled climate carbon cycle project in the Hadley Centre
(Met Office, UK)
Posted September 2005.