From ACT Wiki
Modelling - relationships - non-linear - contrasted with complicated.
Contrasted with merely complicated problems, complex problems are inherently enormously more difficult to analyse and manage.
Complex systems and problems consist of both:
- A large number of interacting elements; and
- Non-linear and unpredictable relationships between the interacting elements, making the system impossible to model reliably using traditional techniques.
For example, climate change is generally considered to be a complex problem (and not merely a complicated one).
- Example - Shortcomings of climate change model include linear estimation
- "A shortcoming of our model build so far is that some economic impacts are linearly estimated: non-linearities are not adequately captured.
- ... it’s not possible to estimate non-linear relationships between temperature increases and economic activity for most channels, especially for temperature increases that have not been observed yet.
- We use multiplicative factors of 5 and 10 to simulate the increasing severity of outcomes from nonlinearities.
- Importantly, the framework does not consider tipping points, events such as the partial disintegration of ice sheets, biosphere collapses or permafrost loss, that pose a threat of abrupt and irreversible climate change...
- ... other research suggests that if tipping points do happen, there could be an x8 increase in climate change associated economic damages."
- Swiss Re Institute - The economics of climate change: no action not an option - April 2021