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Rights: University of Waikato
Published 1 March 2018
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Professor Conrad Pilditch explains the concept of tipping points.

Jargon alert


State changes
Changes to an ecosystem – often from a valued state to a less valued one. For example, a loss of biodiversity due to overfishing. 
Note this is different to changes in states of matter. Considering discussing this term with students to avoid misconceptions.

Hysteresis
When an ecosystem rapidly declines due to small changes, but requires significant changes to return to its original state.
 

Transcript

Professor Conrad Pilditch

These sudden changes in the system, even though there is no direct stressor or direct increase in what we perceive as increasing the amount of stress on the system is known as a tipping point. As a consequence of how these systems are wired, all these complex sets of interactions that are going on between the plants and animals and environment that maintain those goods and services, make them vulnerable to these rapid state changes. This is the science of tipping points.

Often, we can only view a tipping point in hindsight. When we look back up to see what we’ve lost, then we realise what the causes were. The important thing about these tipping points is once you’ve passed one, there is a fundamental shift in how the system is wired. Everything changes and it is very, very difficult to shift that system back into the state that it was in previously because all the things that maintained it in a good way for a long period of time have been reorganised and re-altered and that system, that new state has a hysteresis that makes it very difficult to change.

Acknowledgements
The Science Learning Hub acknowledges the contribution of the Sustainable Seas National Science Challenge and Professor Conrad Pilditch.
Footage supplied by the Sustainable Seas National Science Challenge.