scholarly journals Early warning signals and the prosecutor's fallacy

2012 ◽  
Vol 279 (1748) ◽  
pp. 4734-4739 ◽  
Author(s):  
Carl Boettiger ◽  
Alan Hastings
Keyword(s):  
Early Warning ◽  
Spatial Scales ◽  
Experimental Studies ◽  
Statistical Error ◽  
Warning Signal ◽  
Experimental Manipulation ◽  
Critical Transition ◽  
Natural Experiments ◽  
Warning Signals ◽  
Early Warning Signals

Early warning signals have been proposed to forecast the possibility of a critical transition, such as the eutrophication of a lake, the collapse of a coral reef or the end of a glacial period. Because such transitions often unfold on temporal and spatial scales that can be difficult to approach by experimental manipulation, research has often relied on historical observations as a source of natural experiments. Here, we examine a critical difference between selecting systems for study based on the fact that we have observed a critical transition and those systems for which we wish to forecast the approach of a transition. This difference arises by conditionally selecting systems known to experience a transition of some sort and failing to account for the bias this introduces—a statistical error often known as the prosecutor's fallacy. By analysing simulated systems that have experienced transitions purely by chance, we reveal an elevated rate of false-positives in common warning signal statistics. We further demonstrate a model-based approach that is less subject to this bias than those more commonly used summary statistics. We note that experimental studies with replicates avoid this pitfall entirely.

scholarly journals Variance and Rate-of-Change as Early Warning Signals for a Critical Transition in an Aquatic Ecosystem State: A Test Case From Tasmania, Australia

2018 ◽  
Vol 123 (2) ◽  
pp. 495-508 ◽  
Author(s):  
Kristen K. Beck ◽  
Michael-Shawn Fletcher ◽  
Patricia S. Gadd ◽  
Henk Heijnis ◽  
Krystyna M. Saunders ◽  
...  
Keyword(s):  
Early Warning ◽  
Aquatic Ecosystem ◽  
Rate Of Change ◽  
Test Case ◽  
Critical Transition ◽  
Warning Signals ◽  
Early Warning Signals ◽  
Ecosystem State

scholarly journals Early warning signals of regime shifts in coupled human–environment systems

2016 ◽  
Vol 113 (51) ◽  
pp. 14560-14567 ◽  
Author(s):  
Chris T. Bauch ◽  
Ram Sigdel ◽  
Joe Pharaon ◽  
Madhur Anand
Keyword(s):  
Early Warning ◽  
Warning Signal ◽  
Regime Shifts ◽  
Dynamical Regime ◽  
Ecological Data ◽  
Warning Signals ◽  
Early Warning Signals ◽  
Human Environment ◽  
Environment Model ◽  
External Conditions

In complex systems, a critical transition is a shift in a system’s dynamical regime from its current state to a strongly contrasting state as external conditions move beyond a tipping point. These transitions are often preceded by characteristic early warning signals such as increased system variability. However, early warning signals in complex, coupled human–environment systems (HESs) remain little studied. Here, we compare critical transitions and their early warning signals in a coupled HES model to an equivalent environment model uncoupled from the human system. We parameterize the HES model, using social and ecological data from old-growth forests in Oregon. We find that the coupled HES exhibits a richer variety of dynamics and regime shifts than the uncoupled environment system. Moreover, the early warning signals in the coupled HES can be ambiguous, heralding either an era of ecosystem conservationism or collapse of both forest ecosystems and conservationism. The presence of human feedback in the coupled HES can also mitigate the early warning signal, making it more difficult to detect the oncoming regime shift. We furthermore show how the coupled HES can be “doomed to criticality”: Strategic human interactions cause the system to remain perpetually in the vicinity of a collapse threshold, as humans become complacent when the resource seems protected but respond rapidly when it is under immediate threat. We conclude that the opportunities, benefits, and challenges of modeling regime shifts and early warning signals in coupled HESs merit further research.

Flickering gives early warning signals of a critical transition to a eutrophic lake state

Nature ◽  
2012 ◽  
Vol 492 (7429) ◽  
pp. 419-422 ◽  
Author(s):  
Rong Wang ◽  
John A. Dearing ◽  
Peter G. Langdon ◽  
Enlou Zhang ◽  
Xiangdong Yang ◽  
...  
Keyword(s):  
Early Warning ◽  
Eutrophic Lake ◽  
Critical Transition ◽  
Warning Signals ◽  
Early Warning Signals

Seizures Start without Common Signatures of Critical Transition

2016 ◽  
Vol 26 (08) ◽  
pp. 1650053 ◽  
Author(s):  
Piotr Milanowski ◽  
Piotr Suffczynski
Keyword(s):  
Ocean Circulation ◽  
Early Warning ◽  
Human Subjects ◽  
Epileptic Seizures ◽  
Critical Transition ◽  
Warning Signals ◽  
Early Warning Signals ◽  
Human Epilepsy ◽  
Critical Transitions ◽  
Eeg Recordings

Complex dynamical systems may exhibit sudden autonomous changes from one state to another. Such changes that occur rapidly in comparison to the regular dynamics have been termed critical transitions. Examples of such phenomena can be found in many complex systems: changes in climate and ocean circulation, changes in wildlife populations, financial crashes, as well as in medical conditions like asthma attacks and depression. It has been recognized that critical transitions, even if they arise in completely different contexts and situations, share several common attributes and also generic early-warning signals that indicate that a critical transition is approaching. In the present study, we review briefly the general characteristics that have been observed in systems prior to critical transitions and apply these general indicators to nearly 300 epileptic seizures collected from human subjects using invasive EEG. Only in about 8% of the patients was evidence of critical transitions found. In the remaining majority of cases no early warning signals that behaved consistently prior to seizures were observed. These results do not rule out the possibility of critical transitions to seizure but point to limited relevance of their early warning signals in the context of human epilepsy observed using intracranial EEG recordings.

Mind your metaphors: early warning signals when rolling out strategy

2019 ◽  
Vol 40 (3) ◽  
pp. 10-17 ◽  
Author(s):  
Claudia Jonczyk Sédès
Keyword(s):  
Early Warning ◽  
Warning Signal ◽  
Sales Force ◽  
Strategy Implementation ◽  
Metaphor Analysis ◽  
Warning Signals ◽  
Early Warning Signals ◽  
Content Type ◽  
Implementation Processes ◽  
Early Warning Signal

Purpose While metaphors are widely used in strategy teaching and development, this study aims to present an approach how to benefit from metaphor analysis in strategy implementation. The authors find that metaphors used by organizational actors in strategy implementation processes carry a great range of implicit meanings and tacit knowledge that – when made explicit and critically examined – may serve as early warning signals to anticipate difficult or problematic developments in the strategy rollout phase. Design/methodology/approach The authors conducted narrative interviews with the main protagonists involved in the implementation of a strategic knowledge management project for the sales force of a multinational telecommunication solution provider. The data collected resulted in the surfacing of distinct groups of metaphors used by different organizational groups at different phases of the project implementation. Findings The metaphor analysis showed that metaphors not only reflect but also foreshadow project developments, and thereby reveal organizational conflicts that may erupt at later stages of the strategy implementation. Learning through metaphors can be realized through a sensitization to the detrimental effects of particular metaphors, as well as through the revelation of inconsistencies between the metaphors used and the exposed behaviors. Research limitations/implications The study is an in-depth case study of a strategy implementation project in one organization. While the findings are related to the particular case context, the methodological approach to use metaphor analysis as an early warning signal in strategy implementation can be replicated for strategy implementation processes in general. Practical implications Organizations may use metaphor analysis as a tool to calibrate to what extent their strategy implementation is aligned with initial strategic objectives. Metaphor analysis will be particularly helpful to check if there is an alignment in the implementation approach between different organizational groups. Such analysis can serve as an early warning signal for the strategy implementation phase. Originality/value The approach provides an inexpensive but very effective way of anticipating problematic project developments and unforeseen difficult collaborations during strategy implementation processes. With its focus on metaphors, it captures implicit meanings and connotations that business languages tend to filter out, yet that play a powerful role for enabling or obstructing strategy implementation.

scholarly journals Early warning signals in complex ecosystems

2015 ◽  
Vol 6 (2) ◽  
pp. 2507-2542 ◽  
Author(s):  
I. S. Weaver ◽  
J. G. Dyke
Keyword(s):  
Early Warning ◽  
Warning Signal ◽  
Ecosystem Model ◽  
Robust Methods ◽  
Stable States ◽  
Warning Signals ◽  
Early Warning Signals ◽  
Critical Transitions ◽  
Rapid Changes ◽  
External Driving

Abstract. Given the potential for elements of the Earth system to undergo rapid, hard to reverse changes in state, there is a pressing need to establish robust methods to produce early warning signals of such events. Here we present a conceptual ecosystem model in which a diversity of stable states emerge, along with rapid changes, referred to as critical transitions, as a consequence of external driving and non-linear ecological dynamics. We are able to produce robust early warning signals that precede critical transitions. However, we show that there is no correlation between the magnitude of the signal and magnitude or reversibility of any individual critical transition. We discuss these findings in the context of ecosystem management prior to and post critical transitions. We argue that an understanding of the dynamics of the systems is necessary both for management prior and post critical transitions and the effective interpretation of any early warning signal that may be produced for that system.

Early-Warning Signals for a Critical Transition in the Coupled Amazon Rainforest-South American Monsoon System

2021 ◽  
Author(s):  
Nils Bochow
Keyword(s):  
Early Warning ◽  
Amazon Rainforest ◽  
South American ◽  
Critical Transition ◽  
The South ◽  
Warning Signals ◽  
Early Warning Signals ◽  
South American Monsoon ◽  
Monsoon System ◽  
South American Monsoon System

<p>The Amazon rainforest is widely recognised as a potential tipping element in the Earth's climate system. While several studies suggest a sudden dieback of the rainforest ecosystem after partial deforestation [e.g., 1, 2], there is still a lack of understanding where to search for early-warning signals that might precede such a dieback. In this work we employ a non-linear model of the moisture transport across the Amazon Basin to propose several statistical and physical early warning signals for a critical transition in the coupled dynamics of the Amazon rainforest and the atmospheric circulation of the South American monsoon. </p><p>Widespread deforestation and its effects on evapotranspiration and radiation have been shown to potentially trigger a collapse of the positive feedback related to latent heat release over the rainforest [3], resulting in substantially reduced rainfall amounts. The model includes a nonlinear contribution representing the acceleration of low-level moisture flow caused by condensational latent heating.  </p><p>Guided by our modelling results, we associate characteristic changes in the hydrological cycle as well as statistical indicators in observed data with deforestation-induced circulation changes that are consistent with the identified early-warning signals. Our findings indicate that in response to deforestation, the coupled atmosphere-vegetation system is destabilising and that further deforestation could trigger a transition of the Amazon rainforest to a savanna state. </p><p>[1] Nobre, C. A., & Borma, L. D. S. (2009). “Tipping points” for the Amazon forest. Current Opinion in Environmental Sustainability. https://doi.org/10.1016/j.cosust.2009.07.003</p><p>[2] Hirota, M., Holmgren, M., Van Nes, E. H., & Scheffer, M. (2011). Global resilience of tropical forest and savanna to critical transitions. Science, 334(6053), 232–235. https://doi.org/10.1126/science.1210657</p><p>[3] Boers, N., Marwan, N., Barbosa, H. M. J., & Kurths, J. (2017). A deforestation-induced tipping point for the South American monsoon system. Scientific Reports, 7. https://doi.org/10.1038/srep41489</p>

scholarly journals Catching Critical Transition in Engineered Systems

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Jin Huang ◽  
Tianchuang Meng ◽  
Yangdong Deng ◽  
Fanling Huang
Keyword(s):  
Early Warning ◽  
Multiple Scales ◽  
Stable State ◽  
Critical Threshold ◽  
Supporting Evidence ◽  
Critical Transition ◽  
Warning Signals ◽  
Early Warning Signals ◽  
Critical Transitions ◽  
Engineered Systems

A variety of engineered systems can encounter critical transitions where the system suddenly shifts from one stable state to another at a critical threshold. The critical transition has aroused vital concerns for its potentially disastrous impacts. We validate an often taken-for-granted hypothesis that the failure of engineered systems can be attributed to the respective critical transitions and show how early warning signals are closely associated with critical transitions. We demonstrate that it is feasible to use early warning signals to predict system failures. Our findings open a new path to forecast failures of engineered systems with a generic method and provide supporting evidence for the universal existence of critical transition in dynamical systems at multiple scales.

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