Living dangerously on borrowed time during slow, unrecognized regime shifts
TL;DR: This paper argues that slow responses by ecosystems after transgressing a dangerous threshold also affords borrowed time - a window of opportunity to return to safer conditions before the new state eventually locks in and equilibrates.
Abstract: Regime shifts from one ecological state to another are often portrayed as sudden, dramatic, and difficult to reverse. Yet many regime shifts unfold slowly and imperceptibly after a tipping point has been exceeded, especially at regional and global scales. These long, smooth transitions between equilibrium states are easy to miss, ignore, or deny, confounding management and governance. However, slow responses by ecosystems after transgressing a dangerous threshold also affords borrowed time - a window of opportunity to return to safer conditions before the new state eventually locks in and equilibrates. In this context, the most important challenge is a social one: convincing enough people to confront business-as-usual before time runs out to reverse unwanted regime shifts even after they have already begun.
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TL;DR: The global challenge is to steer reefs through the Anthropocene era in a way that maintains their biological functions and will require radical changes in the science, management and governance of coral reefs.
Abstract: Coral reefs support immense biodiversity and provide important ecosystem services to many millions of people Yet reefs are degrading rapidly in response to numerous anthropogenic drivers In the coming centuries, reefs will run the gauntlet of climate change, and rising temperatures will transform them into new configurations, unlike anything observed previously by humans Returning reefs to past configurations is no longer an option Instead, the global challenge is to steer reefs through the Anthropocene era in a way that maintains their biological functions Successful navigation of this transition will require radical changes in the science, management and governance of coral reefs
1,196 citations
TL;DR: Folke et al. as mentioned in this paper proposed a social-ecological resilience and biosphere-based sustainability science model for sustainable living in ecology and society, 21(3):41, doi:10.5751/ES-08748-210341.
Abstract: CITATION: Folke, C., et al. 2016. Social-ecological resilience and biosphere-based sustainability science. Ecology and Society, 21(3):41, doi:10.5751/ES-08748-210341.
619 citations
TL;DR: Policy-makers are challenged not to categorize all fires as destructive to ecosystems simply because they have long flame lengths and kill most of the trees within the fire boundary.
Abstract: With projected climate change, we expect to face much more forest fire in the coming decades. Policy-makers are challenged not to categorize all fires as destructive to ecosystems simply because they have long flame lengths and kill most of the trees within the fire boundary. Ecological context matters: In some ecosystems, high-severity regimes are appropriate, but climate change may modify these fire regimes and ecosystems as well. Some undesirable impacts may be avoided or reduced through global strategies, as well as distinct strategies based on a forest's historical fire regime.
381 citations
University of Tasmania1, Dalhousie University2, University of California3, University of Auckland4, University of Adelaide5, Simon Fraser University6, University of Oslo7, Pontifical Catholic University of Chile8, University of La Laguna9, University of Cape Town10, University of Barcelona11, Spanish National Research Council12, Tokyo University of Marine Science and Technology13, Laval University14
TL;DR: It is shown that human-derived stressors can act to erode resilience of desirable macroalgal beds while strengthening resilience of urchin barrens, thus exacerbating the risk, spatial extent and irreversibility of an unwanted regime shift for marine ecosystems.
Abstract: A pronounced, widespread and persistent regime shift among marine ecosystems is observable on temperate rocky reefs as a result of sea urchin overgrazing. Here, we empirically define regime-shift dynamics for this grazing system which transitions between productive macroalgal beds and impoverished urchin barrens. Catastrophic in nature, urchin overgrazing in a well-studied Australian system demonstrates a discontinuous regime shift, which is of particular management concern as recovery of desirable macroalgal beds requires reducing grazers to well below the initial threshold of overgrazing. Generality of this regime-shift dynamic is explored across 13 rocky reef systems (spanning 11 different regions from both hemispheres) by compiling available survey data (totalling 10 901 quadrats surveyed in situ ) plus experimental regime-shift responses (observed during a total of 57 in situ manipulations). The emergent and globally coherent pattern shows urchin grazing to cause a discontinuous ‘catastrophic’ regime shift, with hysteresis effect of approximately one order of magnitude in urchin biomass between critical thresholds of overgrazing and recovery. Different life-history traits appear to create asymmetry in the pace of overgrazing versus recovery. Once shifted, strong feedback mechanisms provide resilience for each alternative state thus defining the catastrophic nature of this regime shift. Importantly, human-derived stressors can act to erode resilience of desirable macroalgal beds while strengthening resilience of urchin barrens, thus exacerbating the risk, spatial extent and irreversibility of an unwanted regime shift for marine ecosystems.
380 citations
Cites background from "Living dangerously on borrowed time..."
...It suggests that the time required for urchin populations to build to threshold levels for overgrazing, in addition to the time course of transition from kelp to barrens itself, is much longer than commonly perceived (see ‘Living on borrowed-time concept’ [32])....
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01 Jan 2014
TL;DR: The topics assessed in this chapter were last assessed by the IPCC in 2007, principally in WGII AR4 Chapters 3 (Kundzewicz et al., 2007) and 4 (Fischlin et al, 2007), but also in this paper Sections 1.3.4 and 1.5 (Rosenzweig et al. 2007).
Abstract: The topics assessed in this chapter were last assessed by the IPCC in 2007, principally in WGII AR4 Chapters 3 (Kundzewicz et al., 2007) and 4 (Fischlin et al., 2007), but also in WGII AR4 Sections 1.3.4 and 1.3.5 (Rosenzweig et al., 2007). The WGII AR4 SPM stated “Observational evidence from all continents and most oceans shows that many natural systems are being affected by regional climate changes, particularly temperature increases,” though they noted that documentation of observed changes in tropical regions and the Southern Hemisphere was sparse (Rosenzweig et al., 2007). Fischlin et al. (2007) found that 20 to 30% of the plant and animal species that had been assessed to that time were considered to be at increased risk of extinction if the global average temperature increase exceeds 2°C to 3°C above the preindustrial level with medium confidence, and that substantial changes in structure and functioning of terrestrial, marine, and other aquatic ecosystems are very likely under that degree of warming and associated atmospheric CO2 concentration. No time scale was associated with these findings. The carbon stocks in terrestrial ecosystems were considered to be at high risk from climate change and land use change. The report warned that the capacity of ecosystems to adapt naturally to the combined effect of climate change and other stressors is likely to be exceeded if greenhouse gas (GHG) emission continued at or above the then-current rate.
359 citations
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Stockholm Environment Institute1, Stockholm University2, Australian National University3, University of Alaska Fairbanks4, Université catholique de Louvain5, University of East Anglia6, Wageningen University and Research Centre7, Royal Swedish Academy of Sciences8, Potsdam Institute for Climate Impact Research9, University of Oxford10, James Cook University11, Arizona State University12, Royal Institute of Technology13, University of Minnesota14, University of Vermont15, Stockholm International Water Institute16, California State University San Marcos17, Goddard Institute for Space Studies18, Commonwealth Scientific and Industrial Research Organisation19, University of Arizona20, University of Copenhagen21, Max Planck Society22
TL;DR: In this article, the authors proposed a new approach to global sustainability in which they define planetary boundaries within which they expect that humanity can operate safely. But the proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development.
Abstract: Anthropogenic pressures on the Earth System have reached a scale where abrupt global environmental change can no longer be excluded. We propose a new approach to global sustainability in which we define planetary boundaries within which we expect that humanity can operate safely. Transgressing one or more planetary boundaries may be deleterious or even catastrophic due to the risk of crossing thresholds that will trigger non-linear, abrupt environmental change within continental- to planetary-scale systems. We have identified nine planetary boundaries and, drawing upon current scientific understanding, we propose quantifications for seven of them. These seven are climate change (CO2 concentration in the atmosphere <350 ppm and/or a maximum change of +1 W m-2 in radiative forcing); ocean acidification (mean surface seawater saturation state with respect to aragonite ≥ 80% of pre-industrial levels); stratospheric ozone (<5% reduction in O3 concentration from pre-industrial level of 290 Dobson Units); biogeochemical nitrogen (N) cycle (limit industrial and agricultural fixation of N2 to 35 Tg N yr-1) and phosphorus (P) cycle (annual P inflow to oceans not to exceed 10 times the natural background weathering of P); global freshwater use (<4000 km3 yr-1 of consumptive use of runoff resources); land system change (<15% of the ice-free land surface under cropland); and the rate at which biological diversity is lost (annual rate of <10 extinctions per million species). The two additional planetary boundaries for which we have not yet been able to determine a boundary level are chemical pollution and atmospheric aerosol loading. We estimate that humanity has already transgressed three planetary boundaries: for climate change, rate of biodiversity loss, and changes to the global nitrogen cycle. Planetary boundaries are interdependent, because transgressing one may both shift the position of other boundaries or cause them to be transgressed. The social impacts of transgressing boundaries will be a function of the social-ecological resilience of the affected societies. Our proposed boundaries are rough, first estimates only, surrounded by large uncertainties and knowledge gaps. Filling these gaps will require major advancements in Earth System and resilience science. The proposed concept of "planetary boundaries" lays the groundwork for shifting our approach to governance and management, away from the essentially sectoral analyses of limits to growth aimed at minimizing negative externalities, toward the estimation of the safe space for human development. Planetary boundaries define, as it were, the boundaries of the "planetary playing field" for humanity if we want to be sure of avoiding major human-induced environmental change on a global scale.
4,771 citations
TL;DR: A meta-analysis shows that species are shifting their distributions in response to climate change at an accelerating rate, and that the range shift of each species depends on multiple internal species traits and external drivers of change.
Abstract: The distributions of many terrestrial organisms are currently shifting in latitude or elevation in response to changing climate Using a meta-analysis, we estimated that the distributions of species have recently shifted to higher elevations at a median rate of 110 meters per decade, and to higher latitudes at a median rate of 169 kilometers per decade These rates are approximately two and three times faster than previously reported The distances moved by species are greatest in studies showing the highest levels of warming, with average latitudinal shifts being generally sufficient to track temperature changes However, individual species vary greatly in their rates of change, suggesting that the range shift of each species depends on multiple internal species traits and external drivers of change Rapid average shifts derive from a wide diversity of responses by individual species
3,986 citations
James Cook University1, United States Environmental Protection Agency2, Stockholm University3, University of California, Davis4, University of Queensland5, University of California, San Diego6, Smithsonian Tropical Research Institute7, National Center for Atmospheric Research8, Great Barrier Reef Marine Park Authority9, Stanford University10, National Museum of Natural History11, Natural History Museum12
TL;DR: International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.
Abstract: The diversity, frequency, and scale of human impacts on coral reefs are increasing to the extent that reefs are threatened globally. Projected increases in carbon dioxide and temperature over the next 50 years exceed the conditions under which coral reefs have flourished over the past half-million years. However, reefs will change rather than disappear entirely, with some species already showing far greater tolerance to climate change and coral bleaching than others. International integration of management strategies that support reef resilience need to be vigorously implemented, and complemented by strong policy decisions to reduce the rate of global warming.
3,664 citations
TL;DR: Work in different scientific fields is now suggesting the existence of generic early-warning signals that may indicate for a wide class of systems if a critical threshold is approaching.
Abstract: Complex dynamical systems, ranging from ecosystems to financial markets and the climate, can have tipping points at which a sudden shift to a contrasting dynamical regime may occur. Although predicting such critical points before they are reached is extremely difficult, work in different scientific fields is now suggesting the existence of generic early-warning signals that may indicate for a wide class of systems if a critical threshold is approaching.
3,450 citations
TL;DR: It is found that oceanic absorption of CO2 from fossil fuels may result in larger pH changes over the next several centuries than any inferred from the geological record of the past 300 million years.
Abstract: The coming centuries may see more ocean acidification than the past 300 million years. Most carbon dioxide released into the atmosphere as a result of the burning of fossil fuels will eventually be absorbed by the ocean1, with potentially adverse consequences for marine biota2,3,4. Here we quantify the changes in ocean pH that may result from this continued release of CO2 and compare these with pH changes estimated from geological and historical records. We find that oceanic absorption of CO2 from fossil fuels may result in larger pH changes over the next several centuries than any inferred from the geological record of the past 300 million years, with the possible exception of those resulting from rare, extreme events such as bolide impacts or catastrophic methane hydrate degassing.
3,060 citations