What do we mean, ’tipping cascade’?

Abstract Based on suggested interactions of potential tipping elements in the Earth’s climate and in ecological systems, tipping cascades as possible dynamics are increasingly discussed and studied as their activation would impose a considerable risk for human societies and biosphere integrity. However, there are ambiguities in the description of tipping cascades within the literature so far. Here we illustrate how different patterns of multiple tipping dynamics emerge from a very simple coupling of two previously studied idealized tipping elements. In particular, we distinguish between a two phase cascade, a domino cascade and a joint cascade. While a mitigation of an unfolding two phase cascade may be possible and common early warning indicators are sensitive to upcoming critical transitions to a certain degree, the domino cascade may hardly be stopped once initiated and critical slowing down–based indicators fail to indicate tipping of the following element. These different potentials for intervention and anticipation across the distinct patterns of multiple tipping dynamics should be seen as a call to be more precise in future analyses on cascading dynamics arising from tipping element interactions in the Earth system.

Download Full-text

The collision that changed the world

Elem Sci Anth ◽

10.12952/journal.elementa.000061 ◽

2015 ◽

Vol 3 ◽

Author(s):

Wally Broecker

Keyword(s):

Fossil Fuels ◽

Isotope Composition ◽

Slowing Down ◽

Indian Land ◽

The Earth ◽

Abrupt Changes ◽

Long Time ◽

Sulfur Isotope Composition ◽

Earth’S Climate

Abstract In connection with the Anthropocene, one might ask how climate is likely to evolve in the absence of man’s intervention and whether humans will be able to purposefully alter this course. In this commentary, I deal with the situation for very long time scales. I make a case that fifty million years ago, the collision between the northward drifting Indian land mass and Asia set the Earth’s climate on a new course. Ever since then, it has cooled. In the absence of some other dramatic disruption in the movement of the plates which make up our planet’s crust, on the time scale of tens of millions of years, this drift would cause the Earth to freeze over as it did during the late Precambrian. Evidence for this change in course comes from records of oxygen and lithium isotopic composition of foraminifer shells. It is reinforced by records of Mg to Ca in halite-hosted fluid inclusions and in marine CaCO3. In addition, the collision appears to have created abrupt changes in the sulfur isotope composition of marine barite and the carbon isotope composition of amber. Not only did this collision create the Himalaya, but more important, it led to a reorganization of the crustal plate motions. Through some combination of the building of mountains and lowering of sea level, these changes generated a mismatch between the supply of CO2 by planetary outgassing and that of calcium by the weathering of silicate rock. The tendency toward an oversupply of calcium has been compensated by a drawdown of the atmosphere’s CO2 content. This drawdown cooled the Earth, slowing down the supply of calcium. Although we are currently inadvertently compensating for this cooling by burning fossil fuels, the impacts of this CO2 on Earth climate will last no more than a tenth of a million years. So, if humans succeed in avoiding extinction, there will likely be a long-term effort to warm the planet.

Download Full-text

Quantifying limits to detection of early warning for critical transitions

Journal of The Royal Society Interface ◽

10.1098/rsif.2012.0125 ◽

2012 ◽

Vol 9 (75) ◽

pp. 2527-2539 ◽

Cited By ~ 103

Author(s):

Carl Boettiger ◽

Alan Hastings

Keyword(s):

Early Warning ◽

Error Rates ◽

Warning Signs ◽

False Alarms ◽

Natural Systems ◽

Return Times ◽

Model Based ◽

Critical Transitions ◽

Early Warning Indicators ◽

Warning Indicators

Catastrophic regime shifts in complex natural systems may be averted through advanced detection. Recent work has provided a proof-of-principle that many systems approaching a catastrophic transition may be identified through the lens of early warning indicators such as rising variance or increased return times. Despite widespread appreciation of the difficulties and uncertainty involved in such forecasts, proposed methods hardly ever characterize their expected error rates. Without the benefits of replicates, controls or hindsight, applications of these approaches must quantify how reliable different indicators are in avoiding false alarms, and how sensitive they are to missing subtle warning signs. We propose a model-based approach to quantify this trade-off between reliability and sensitivity and allow comparisons between different indicators. We show these error rates can be quite severe for common indicators even under favourable assumptions, and also illustrate how a model-based indicator can improve this performance. We demonstrate how the performance of an early warning indicator varies in different datasets, and suggest that uncertainty quantification become a more central part of early warning predictions.

Download Full-text

Overlapping Time Scales Obscure Early Warning Signals for the Second COVID-19 Wave

10.1101/2021.07.27.21261226 ◽

2021 ◽

Author(s):

Fabian Dablander ◽

Hans Heesterbeek ◽

Denny Borsboom ◽

John M. Drake

Keyword(s):

Time Scales ◽

Early Warning ◽

Critical Slowing Down ◽

Multiple Time Scales ◽

Unexpected Finding ◽

Multiple Time ◽

Slowing Down ◽

Early Warning Indicators ◽

Second Wave ◽

Warning Indicators

Early warning indicators based on critical slowing down have been suggested as a model-independent and low-cost tool to anticipate the (re)emergence of infectious diseases. We studied whether such indicators could reliably have anticipated the second COVID-19 wave in European countries. Contrary to theoretical predictions, we found that characteristic early warning indicators generally decreased rather than increased prior to the second wave. A model explains this unexpected finding as a result of transient dynamics and the multiple time scales of relaxation during a non-stationary epidemic. Particularly, if an epidemic that seems initially contained after a first wave does not fully settle to its new quasi-equilibrium prior to changing circumstances or conditions that force a second wave, then indicators will show a decreasing rather than an increasing trend as a result of the persistent transient trajectory of the first wave. Our simulations show that this lack of time scale separation was to be expected during the second European epidemic wave of COVID-19. Overall, our results emphasize that the theory of critical slowing down applies only when the external forcing of the system across a critical point is slow relative to the internal system dynamics.

Download Full-text

4. The Great Acceleration

Anthropocene: A Very Short Introduction ◽

10.1093/actrade/9780198792987.003.0004 ◽

2018 ◽

pp. 52-74

Author(s):

Erle C. Ellis

Keyword(s):

Environmental Change ◽

Global Environmental Change ◽

System Level ◽

Earth System ◽

System A ◽

The Earth ◽

System P ◽

Global Environmental ◽

Earth’S Climate ◽

Great Acceleration

The challenge for the International Geosphere-Biosphere Programme (IGBP) in 1999 was how to integrate the evidence of humans transforming Earth’s functioning as a system into a coherent overview of global environmental change. The IGBP report Global Change and the Earth System: A Planet Under Pressure (2004) identified a dramatic mid-20th-century step-change in anthropogenic global environmental change, which would come to be called ‘The Great Acceleration’. ‘The Great Acceleration’ outlines the complex, multi-causal, system-level set of processes that have altered the Earth system, from domestication of land to human alterations of the atmosphere, hydrosphere, and biosphere. It also discusses tipping points that result in relatively rapid, non-linear, and potentially irreversible ‘step-changes’ in Earth’s climate system.

Download Full-text

3. Regulation

Earth System Science: A Very Short Introduction ◽

10.1093/actrade/9780198718871.003.0003 ◽

2016 ◽

pp. 38-56

Author(s):

Tim Lenton

Keyword(s):

Carbon Dioxide ◽

Atmospheric Carbon Dioxide ◽

Atmospheric Oxygen ◽

Biogeochemical Cycles ◽

Global Temperature ◽

Earth System ◽

Animal Life ◽

The Past ◽

The Earth ◽

Earth’S Climate

The Earth system has maintained habitable conditions for life over geological periods of time. These conditions include an equable global temperature, enough atmospheric carbon dioxide to fuel photosynthesis, and sufficient nutrients to grow. Furthermore, for at least the past 370 million years there has been enough atmospheric oxygen to support complex, mobile animal life, but not so much that wildfires decimated vegetation. ‘Regulation’ introduces the ways in which the biogeochemical cycles of the Earth system are self-regulated, how they are coupled to the Earth’s climate, and how scientists study this regulation.

Download Full-text

Evaluating early-warning indicators of critical transitions in natural aquatic ecosystems

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1608242113 ◽

2016 ◽

Vol 113 (50) ◽

pp. E8089-E8095 ◽

Cited By ~ 56

Author(s):

Alena Sonia Gsell ◽

Ulrike Scharfenberger ◽

Deniz Özkundakci ◽

Annika Walters ◽

Lars-Anders Hansson ◽

...

Keyword(s):

Time Series ◽

Case Studies ◽

Early Warning ◽

Aquatic Ecosystems ◽

Theoretical Models ◽

Freshwater Ecosystems ◽

State Variables ◽

Critical Transitions ◽

Early Warning Indicators ◽

Warning Indicators

Ecosystems can show sudden and persistent changes in state despite only incremental changes in drivers. Such critical transitions are difficult to predict, because the state of the system often shows little change before the transition. Early-warning indicators (EWIs) are hypothesized to signal the loss of system resilience and have been shown to precede critical transitions in theoretical models, paleo-climate time series, and in laboratory as well as whole lake experiments. The generalizability of EWIs for detecting critical transitions in empirical time series of natural aquatic ecosystems remains largely untested, however. Here we assessed four commonly used EWIs on long-term datasets of five freshwater ecosystems that have experienced sudden, persistent transitions and for which the relevant ecological mechanisms and drivers are well understood. These case studies were categorized by three mechanisms that can generate critical transitions between alternative states: competition, trophic cascade, and intraguild predation. Although EWIs could be detected in most of the case studies, agreement among the four indicators was low. In some cases, EWIs were detected considerably ahead of the transition. Nonetheless, our results show that at present, EWIs do not provide reliable and consistent signals of impending critical transitions despite using some of the best routinely monitored freshwater ecosystems. Our analysis strongly suggests that a priori knowledge of the underlying mechanisms driving ecosystem transitions is necessary to identify relevant state variables for successfully monitoring EWIs.

Download Full-text

Critical transitions in Earth system dynamics

10.5194/egusphere-egu21-357 ◽

2021 ◽

Author(s):

Niklas Boers

Keyword(s):

Stability Loss ◽

Meridional Overturning Circulation ◽

Earth System ◽

Critical Thresholds ◽

Critical Transitions ◽

The Earth ◽

System Components ◽

Polar Ice Sheets ◽

Proxy Reconstructions ◽

The Stability

<p>It has been argued that several components of the Earth system may destabilise in response to gradually changing forcing such as rising atmospheric greenhouse gas concentrations and temperatures. Key examples of potentially unstable parts of the Earth system include the polar ice sheets and sea ice cover, the Atlantic Meridional Overturning Circulation, as well as tropical rainforests and monsoon systems. There are reasons to believe that the leading dynamical modes of these subsystems may essentially mimic bifurcations in low-order random dynamical systems. The stability loss on the way to critical transitions associated with such bifurcations typically leaves characteristic imprints in the statistics of time series encoding the dynamics of the system in question, which can hence serve as a proxy to assess the stability of the system. Here, we present recent advances in detecting stability loss along these lines and investigate proxy reconstructions and observations of several of the Earth system components that have been proposed to be at risk of destabilisation. We discuss the control parameters relevant for the different Earth system components and report on the posterior distributions of the critical thresholds, beyond which stability would be lost.&#160;</p>

Download Full-text