Early warning of regime shifts
Rising variance, autocorrelation and slower recovery in long ecological series are tested as signals of approaching transitions in lakes, reefs and drylands.
The Global Centre for Risk and Innovation (GCRI)
Ecosystems and the social and economic systems that use them interact through feedbacks, thresholds and networks. Complex systems methods explore how those interactions produce regime shifts, cascades of extinction and correlated losses that simpler models miss, and they stress test management against them.
GCRI · Established · service level R0
Regime shifts are large, persistent changes in ecosystems that complex systems methods help anticipate and explain. These methods model feedbacks, thresholds and networks linking ecosystems with the social and economic systems that use them, exploring cascades of extinction and correlated losses that simpler models miss.
The working screen behind this method: its structure, terms and states. Names are placeholders and values illustrative.
Biodiversity · Complex systems in ecology · Run R-7901
| Protected area authority | adapts after 5 losses | 0.2 | survey, labelled |
| Environment ministry | adapts after 5 losses | 0.2 | survey, labelled |
| Indigenous and local community council | adapts after 2 losses | 0.4 | survey, labelled |
Complex systems and agent-based modelling study systems whose behaviour emerges from interactions among many components. They help explain nonlinear dynamics, tipping points and collective behaviour. In biodiversity and nature, climate and hazards and oceans and coasts, complex systems approaches explore how interacting risks can produce sudden, systemic shifts. They support stress testing of policies against emergent behaviour. The canonical description is on the STEM Commons.
Rising variance, autocorrelation and slower recovery in long ecological series are tested as signals of approaching transitions in lakes, reefs and drylands.
Interaction networks of plants, pollinators, predators and prey are simulated to see how the loss of one species propagates through the web.
Farmers, fishers, traders and regulators are represented as agents to explore how incentives, rules and ecology together drive clearing, overfishing or recovery.
Each term as this page uses it. Where a standard-setting body defines the term, the wording follows that body.
| Term | Definition |
|---|---|
| Early warning signal | A statistical change, such as rising variance or slower recovery, that can precede a regime shift. |
| Co-extinction | The loss of a species because a species it depends on, such as a host or pollinator, is lost. |
| Social-ecological system | A linked system of people and nature in which each shapes the other through feedbacks. |
Mountain ranges, deserts, wetlands, glaciers and reefs, and how remote each division is from large cities, shown for Pacific Island states as an example geography for this subject.
Data from the source register feeds the methods; calibration and an independent test gate the estimate and its limits; the decision stays with the competent authority.
Fig. 01Nodes carry their type, metrics and state; connectors show what feeds what; the gates are the validation steps; the timeline is one application. Design of the method's use, not a record of a run.
Datasets and records used by complex systems and agent-based modelling on this platform, with the role each plays and the label its values carry. Sources are listed in the source register.
| Data | Role | Label |
|---|---|---|
| Long-term ecological time series | Early warning indicators | OBSERVED |
| Species interaction networks | Network structure | OBSERVED |
| Land-use and fisheries surveys | Calibration of agent behaviour | REPORTED |
| Model ensembles | Structural uncertainty | MODELLED |
Models are evaluated by matching multiple stylised facts and patterns at different scales. Sensitivity and robustness analysis test dependence on assumptions.
| Check | How it is done |
|---|---|
| Pattern-oriented validation | Models must reproduce several observed patterns at different scales, not a single target |
| Sensitivity and robustness | Conclusions are tested across parameter ranges and alternative model structures |
| False alarm testing | Early warning methods are tested on series with and without known transitions |
Many plausible models can reproduce the same patterns. Calibration and validation data are often limited.
Systems Science and Modelling stewards complex systems and agent-based modelling for the Consortium and reviews how it is applied across platforms.
The current service level is R0: information and enquiries. An enquiry receives a reference and names the next step; applications, payments, compute allocations and registrations open only when their team, terms and review capacity exist.