Richardson et al..pdf

S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E E N V I RO N M E N TA L S T U D I E S Copyright © 2023 The...

S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E E N V I RO N M E N TA L S T U D I E S Copyright © 2023 The Authors, some Earth beyond six of nine planetary boundaries rights reserved; exclusive licensee American Association Katherine Richardson1*, Will Steffen2†, Wolfgang Lucht3,4, Jørgen Bendtsen1, Sarah E. Cornell5, for the Advancement Jonathan F. Donges3,5, Markus Drüke3, Ingo Fetzer5,6, Govindasamy Bala7, Werner von Bloh3, of Science. No claim to Georg Feulner3, Stephanie Fiedler8, Dieter Gerten3,4, Tom Gleeson9,10, Matthias Hofmann3, original U.S. Government Willem Huiskamp3, Matti Kummu11, Chinchu Mohan8,12,13, David Nogués-Bravo1, Stefan Petri3, Works. Distributed Miina Porkka11, Stefan Rahmstorf3,14, Sibyll Schaphoff3, Kirsten Thonicke3, Arne Tobian3,5, under a Creative Commons Attribution Vili Virkki11, Lan Wang-Erlandsson3,5,6, Lisa Weber8, Johan Rockström3,5,15 NonCommercial License 4.0 (CC BY-NC). This planetary boundaries framework update finds that six of the nine boundaries are transgressed, suggesting that Earth is now well outside of the safe operating space for humanity. Ocean acidification is close to being breached, while aerosol loading regionally exceeds the boundary. Stratospheric ozone levels have slightly re- covered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 production drives Earth system biosphere functions, human appropriation of net primary production is pro- posed as a control variable for functional biosphere integrity. This boundary is also transgressed. Earth system modeling of different levels of the transgression of the climate and land system change boundaries il- lustrates that these anthropogenic impacts on Earth system must be considered in a systemic context. INTRODUCTION global environmental conditions remain uncertain. Paleoclimate re- The planetary boundaries framework (1, 2) draws upon Earth search, however, documents that Earth has previously experienced system science (3). It identifies nine processes that are critical for largely ice-free conditions during warm periods (6, 7) with corre- maintaining the stability and resilience of Earth system as a spondingly different states of the biosphere. It is clearly in human- whole. All are presently heavily perturbed by human activities. ity’s interest to avoid perturbing Earth system to a degree that risks The framework aims to delineate and quantify levels of anthropo- changing global environmental conditions so markedly. Ice cover is genic perturbation that, if respected, would allow Earth to remain in only one indicator of substantial system-wide change in numerous a “Holocene-like” interglacial state. In such a state, global environ- other Earth system dimensions. The planetary boundaries frame- mental functions and life-support systems remain similar to those work delineates the biophysical and biochemical systems and pro- experienced over the past ~10,000 years rather than changing into a cesses known to regulate the state of the planet within ranges that state without analog in human history. This Holocene period, which are historically known and scientifically likely to maintain Earth began with the end of the last ice age and during which agriculture system stability and life-support systems conducive to the human and modern civilizations evolved, was characterized by relatively welfare and societal development experienced during the Holocene. stable and warm planetary conditions. Human activities have now Currently, anthropogenic perturbations of the global environ- brought Earth outside of the Holocene’s window of environmental ment are primarily addressed as if they were separate issues, e.g., variability, giving rise to the proposed Anthropocene epoch (4, 5). climate change, biodiversity loss, or pollution. This approach, Planetary-scale environmental forcing by humans continues and however, ignores these perturbations’ nonlinear interactions and re- individual Earth system components are, to an increasing extent, in sulting aggregate effects on the overall state of Earth system. Plane- disequilibrium in relation to the changing conditions. As a conse- tary boundaries bring a scientific understanding of anthropogenic quence, the post-Holocene Earth is still evolving, and ultimate global environmental impacts into a framework that calls for con- sidering the state of Earth system as a whole. 1 For >3 billion years, interactions between the geosphere (energy Globe Institute, Faculty of Health, University of Copenhagen, Copenhagen, Denmark. 2Australian National University, Canberra, Australia. 3Potsdam Institute flow and nonliving materials in Earth and atmosphere) and bio- for Climate Impact Research (PIK), Member of the Leibniz Association, Potsdam, sphere (all living organisms/ecosystems) have controlled global en- Germany. 4Department of Geography, Humboldt-Universität zu Berlin, Berlin, vironmental conditions. Earth system’s state changed in response to Germany. 5Stockholm Resilience Centre, Stockholm University, Stockholm, Sweden. 6Bolin Centre for Climate Research, Stockholm University, Stockholm, forcings generated by external perturbations (e.g., solar energy Sweden. 7Centre for Atmospheric and Oceanic Sciences, Indian Institute of input and bolide strikes) or internal processes in the geosphere Science, Bangalore, Karnataka – 560012, India. 8GEOMAR Helmholtz Centre for (e.g., plate tectonics and volcanism) or biosphere (e.g., evolution Ocean Research Kiel and Faculty for Mathematics and Natural Sciences, Chris- tian-Albrechts-University Kiel, Kiel, Germany. 9Department of Civil Engineering, of photosynthesis and rise of vascular plants). These forcings were University of Victoria, Victoria, British Columbia, Canada. 10School of Earth and processed through interactions and feedbacks among processes and Ocean Sciences, University of Victoria, Victoria, British Columbia, Canada. 11 systems within Earth system, shaping its often complex overall re- Water and Development Research Group, Aalto University, Espoo, Finland. sponse. Today, human activities with planetary-scale effects act as 12 Global Institute for Water Security, University of Saskatchewan, Saskatoon, Sas- katchewan, Canada. 13Waterplan (YC S21), San Francisco, CA, USA. 14Institute of additional forcing on Earth system. Thus, the anthroposphere has Physics and Astronomy, University of Potsdam, Potsdam, Germany. 15Institute become an additional functional component of Earth system (3, for Environmental Science and Geography, University of Potsdam, Potsdam, 8), capable of altering Earth system state. The planetary boundaries Germany. *Corresponding author. Email: [email protected] framework formulates limits to the impact of the anthroposphere †Deceased. on Earth system by identifying a scientifically based safe operating Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 1 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E space for humanity that can safeguard both Earth’s interglacial state of Earth system by bringing together currently available evidence and its resilience. for the relevant processes and their interactions from different dis- The Holocene state of Earth is the benchmark reference in this ciplines and sources. context, as many of the components comprising the planetary The nine boundaries all represent components of Earth system boundary framework were rather stable during this period. This is critically affected by anthropogenic activities and relevant to Earth’s also the only Earth system state civilizations have historically overall state. For each of the boundaries, control variables are known. Climate is a manifestation of external forcing, e.g., solar ac- chosen to capture the most important anthropogenic influence at tivity, orbital cycles, and interactions among Earth system compo- the planetary level of the boundary in focus. For example, land nents, and global mean surface temperature varied by only ±0.5°C system change arises from myriad human activities, ultimately ag- (9) from the Neolithic [~9000 before the present (B.P.)] until the gregating to alteration of biomes. From a planetary perspective Industrial Revolution. Biomes across Earth have also largely been however, during the Holocene, forests were the land biome with stable over the past 10,000 years, with preindustrial global terrestrial the strongest functional coupling to the climate system (11, 12). net primary production (NPP) varying by not >55.9 ± 1.1 billion Therefore, global reduction in forest area is adopted as the control tonnes (Gt) of C year−1 (2σ) (see the Supplementary Materials). variable representing all land system change. Similarly, the control Bias-corrected data (10) confirm that preindustrial global precipita- variable introduced here for the functional component of the bio- Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 tion levels were also stable, particularly from the mid-Holocene sphere integrity boundary, human appropriation of NPP (HANPP), onward. These data provide strong support for using the Holocene focuses on the ability of the biosphere as a whole to provide func- (see the Supplementary Materials) as the planetary boundaries ref- tional feedbacks in Earth system. Control variables should ideally erence state for a stable and resilient planet. lend themselves to empirical determination and be computable All of the framework’s individual boundaries therefore adopt for use in Earth system projections (e.g., process-based simulation preindustrial Holocene conditions as a reference for assessing the of future change in forest cover) where possible. magnitude of anthropogenic deviations. Available data and state Boundary positions do not demarcate or predict singular thresh- of knowledge from analytics and modeling of the framework com- old shifts in Earth system state. They are placed at a level where the ponents dictate the methods for derivation and quantification of the available evidence suggests that further perturbation of the individ- individual boundaries and their precautionary guardrails. Despite ual process could potentially lead to systemic planetary change by data constraints, efforts have been made to identify suitable altering and fundamentally reshaping the dynamics and spatiotem- control variables for all boundaries, together with evidence of poral patterns of geosphere-biosphere interactions and their feed- how much perturbation leads to generation of impacts or altered backs (13, 14). interactions/feedbacks that can potentially cause irreversible Zone of increasing risk (of Earth system losing Holocene-like changes to Earth’s life support systems. The focus is always at characteristics) is now used to assess the status for transgressed Earth system rather than regional scale, even when the evidence boundaries rather than the “zone of uncertainty” (2) as demarcation used to establish boundaries originates from regional studies. In of this zone is based on more than what is usually referred to as sci- these cases, regional evidence is combined to assess Earth system entific uncertainty. A large body of recent research [e.g., (15–17)] impacts of cumulative transgressions across multiple region- provides strong evidence supporting the conclusion (2) that the al systems. climate change and biosphere integrity boundaries are in a zone The planetary boundaries framework has attracted considerable of rapidly increasing and systemically linked risks. This strengthens scientific and societal attention, inspiring governance strategies and the rationale for using the precautionary principle to set the plane- policies at all levels. The framework evolves through updates made tary boundaries at the lower end of the zone of increasing risk. For in light of recent scientific understanding. Here, we bring together example, for the climate change planetary boundary, we retain the advances from different fields of science to update the framework boundary of 350 parts per million (ppm) CO2 with the zone of in- and the status of its boundaries. Boundaries are, for the first time, creasing risk ranging from 350 to 450 ppm before reaching high proposed for all of the individual components of the framework. risk. This corresponds approximately to a range of global mean Updates of the functional biosphere integrity and aerosol loading surface temperature rise of 1° to 2°C (assuming mainstream scenar- boundaries are based on analyses presented here. Recent analyses ios on non-CO2 forcing). Precaution places the planetary boundary form the basis for updates of the freshwater change and novel enti- at the start of increasing risk (350 ppm ≈ 1°C), i.e., slightly below the ties boundaries. Last, the importance of considering human impacts 1.5°C target identified in the Paris Agreement. The 1.5°C target is on components of the global environment in a system context is il- one that science increasingly demonstrates is associated with sub- lustrated using a modeling exercise exploring how various scenarios stantial risk of triggering irreversible large change and that crossing of transgression of the land system (representing the biosphere) and tipping points cannot be excluded even at lower temperature in- climate change boundaries combine to affect Earth system creases (18). In recognition of the buffering resilience of Earth characteristics. system, most boundaries are nevertheless set at values higher than their observed range through the Holocene up to the Industrial Rev- Framework components olution (for CO2 ≈ 280 ppm) (see the Supplementary Materials). Understanding how biosphere, anthroposphere, and geosphere pro- The stability and characteristic range of variability of interglacial cesses interact with one another is a prerequisite for developing re- Earth system states in Pleistocene paleoclimate (19) and Earth liable projections of possible future Earth system trajectories. A fully system modeling (20) suggest that Earth system would likely process-based understanding of the interactions between these remain in a stable, Holocene-like state if all boundaries were re- domains is, however, still only partially available. The planetary spected despite their being at least temporarily outside the envelope boundaries framework calls for more deeply integrated modeling of Holocene variability. Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 2 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E The distinction between zones of “increasing” and “high” risk complexity. We retain the boundary level of 100 E/MSY (24–26). Of an estimated 8 million Throughout Earth’s history, geosphere-biosphere interactions plant and animal species, around 1 million are threatened with ex- were an internal driver of Earth system state. The climate change tinction (16), and over 10% of genetic diversity of plants and planetary boundary is used here as a proxy for the geosphere. There- animals may have been lost over the past 150 years (23). Thus, the Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 fore, climate change and biosphere integrity are identified as “core genetic component of the biosphere integrity boundary is markedly boundaries” (2) in the framework. The introduction of novel enti- exceeded (Fig. 1 and Table 1). ties is a new anthropogenic driver of Earth system change that, if Previously, Steffen et al. (2) proposed using the Biodiversity In- sufficiently transgressed, could, on its own, alter Earth system tactness Index (BII) (27), an empirically based metric of human state. However, this planetary boundary acts largely through pertur- impacts on population abundances, as an interim proxy for func- bation of the core boundaries, especially biosphere integrity. In con- tional biosphere integrity. It was noted, however, that the link of trast to the definition applied earlier (2) where “naturally occurring BII to Earth system functions remains poorly understood and BII elements mobilized by anthropogenic activities” were included, the cannot be directly linked to the planetary biogeochemical and definition of novel entities is now restricted to include only entities energy flows relevant for establishing Earth system state. In addi- that, in the absence of the anthroposphere, are not present in tion, BII relies on expert elicitation to estimate temporal changes Earth system. in species abundances/distributions, and this knowledge is not Quantifying interactions between boundaries remains a major readily available for many regions, including the oceans. Martin challenge. However, some progress has been made since the last et al. (28) have also recently suggested that BII only partially reflects framework update (2). Recent studies (13, 14, 21, 22) have shown human impacts on Earth system. that additional or more extensive transgression of one planetary We therefore now replace this metric with a computable proxy boundary can change risk gradients for other boundaries. For for photosynthetic energy and materials flow into the biosphere example, there is increasing evidence to suggest that transgressing (29), i.e., net primary production (NPP), and define the functional either the climate change or biosphere integrity planetary boundary component of the biosphere integrity boundary as a limit to the can potentially lead to more steeply increasing risk in the other (21). human appropriation of the biosphere’s NPP (HANPP) as a frac- In the current absence of a comprehensive Earth system model that tion of its Holocene NPP. NPP is fundamental for both ecosystems fully captures interactions between all component spheres, we and human societies as it supports their maintenance, reproduc- explore below how various scenarios of transgression of the land tion, differentiation, networking, and growth. Biomes depend on system (representing the biosphere) and climate change boundaries the energy flow associated with NPP to maintain their planetary combine to control biologically mediated carbon storage at the ecological functions as integral parts of Earth system. NPP-based planetary level. energy flows into human societies should therefore not substantially compromise the energy flow to the biosphere (30). The proxy com- plements the diversity-based dimensions of biosphere integrity, RESULTS covered by the genetic component, which captures the importance Biosphere integrity of variability in living organisms for the functioning of ecosystems. Myriad interactions with the geosphere make the biosphere a con- The suitability of NPP and HANPP for defining a planetary boun- stitutional component of Earth system and a major factor in regu- dary has previously been discussed by Running (31) and Haberl lating its state. The planetary functioning of the biosphere et al. (32). ultimately rests on its genetic diversity, inherited from natural selec- We determine the terrestrial biosphere’s Holocene NPP to have tion not only during its dynamic history of coevolution with the ge- been 55.9 Gt of C year−1 (2σ) and exceedingly stable, varying by not osphere but also on its functional role in regulating the state of Earth more than ±1.1 Gt of C year−1 despite regional variations in time system. Genetic diversity and planetary function, each measured (see the Supplementary Materials). Our model analyses suggest through suitable proxies, are therefore the two dimensions that that NPP still had a Holocene-like level in 1700 (56.2 Gt of C form the basis of a planetary boundary for biosphere integrity. As year−1 for potential natural vegetation and 54.7 Gt of C year−1 applied here, “integrity” does not imply an absence of biosphere when land use is taken into account). By 2020, potential natural change but, rather, change that preserves the overall dynamic and NPP would have risen to 71.4 Gt of C year−1 because of carbon fer- adaptive character of the biosphere. tilization, a disequilibrium response of terrestrial plant physiology Rockström et al. (1) defined the planetary boundary for change to anthropogenically increasing CO2 concentration in the atmo- in genetic diversity as the maximum extinction rate compatible with sphere, whereas actual NPP was 65.8 Gt of C year−1 due to the preserving the genetic basis of the biosphere’s ecological Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 3 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 Fig. 1. Current status of control variables for all nine planetary boundaries. Six of the nine boundaries are transgressed. In addition, ocean acidification is approach- ing its planetary boundary. The green zone is the safe operating space (below the boundary). Yellow to red represents the zone of increasing risk. Purple indicates the high-risk zone where interglacial Earth system conditions are transgressed with high confidence. Values for control variables are normalized so that the origin represents mean Holocene conditions and the planetary boundary (lower end of zone of increasing risk, dotted circle) lies at the same radius for all boundaries (except for the wedges representing green and blue water, see main text). Wedge lengths are scaled logarithmically. The upper edges of the wedges for the novel entities and the genetic diversity component of the biosphere integrity boundaries are blurred either because the upper end of the zone of increasing risk has not yet been quantitatively defined (novel entities) or because the current value is known only with great uncertainty (loss of genetic diversity). Both, however, are well outside of the safe operating space. Transgression of these boundaries reflects unprecedented human disruption of Earth system but is associated with large scientific uncertainties. NPP-reducing effects of global land-use (see the Supplementary example, in some Amazonian regions (34) and northern European Materials). forests. HANPP designates both the harvesting and the elimination or As NPP is the basis for the energy and materials flow that under- alteration (mostly reduction) of potential natural NPP (32), pins the biosphere’s functioning (30), we argue that today’s plane- mainly through agriculture, silviculture, and grazing. Terrestrial tary-scale impact of HANPP is reflected in the observation that HANPP can be estimated both as a fraction of potential natural major indicators of the state of the biosphere show large and wor- NPP [15.7% in 1950 and 23.5% in 2020; inferred from (33) and risome declines in recent decades (16). This suggests that current the Supplementary Materials] and of Holocene mean NPP (30% HANPP is well beyond a precautionary planetary boundary or 16.8 Gt of C year−1 in 2020; see the Supplementary Materials). aiming to safeguard the functional integrity of the biosphere and We argue that an NPP-based planetary boundary limiting HANPP likely already into the high-risk zone. We therefore provisionally should be set in relation to preindustrial Holocene mean NPP and set the functional component of the biosphere integrity planetary not the current potential natural NPP. This is because the global in- boundary at human appropriation of 10% of preindustrial Holocene crease in NPP due to anthropogenic carbon fertilization constitutes mean NPP, shifting into the zone of high risk at 20%. The boundary a resilience response of Earth system that dampens the magnitude of thus defined was transgressed in the late 19th century, a time of con- anthropogenic warming. Hence, the NPP contribution to a carbon siderable acceleration in land use globally (35) with strong impacts sink associated with CO2 fertilization should be protected and sus- on species (27), already leading to early concerns about the effects of tained rather than considered as being available for harvesting. Ex- this large-scale land transformation. amples of large land areas under human use with declining carbon Thus, while the climate warming problem became evident in the sinks, some even turning into carbon sources, i.e., due to human 1980s, problems arising in functional biosphere integrity due to overexploitation of biomass, are already being observed, for human land use began a century earlier. Since the 1960s, growth Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 4 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E Table 1. Current status for the planetary boundaries. Earth Control variable(s) Planetary boundary Preindustrial Upper end of Current value of control system process Holocene zone of variable base value increasing risk Climate change Atmospheric CO2 350 ppm CO2 280 ppm CO2 450 ppm CO2 417 ppm CO2 (41) concentration (ppm CO2) Total anthropogenic +1.0 W m−2 0 W m−2 +1.5 W m−2 +2.91 W m−2 (41) radiative forcing at top-of- atmosphere (W m−2) Change in Genetic diversity: E/MSY 100 E/MSY (24–26) biosphere aspirational goal of ca. 1 E/ integrity MSY (assumed background rate of extinction loss) Functional integrity: HANPP (in billion tonnes of C 1.9% (2σ 20% HANPP 30% HANPP (see the Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 measured as energy year−1) 90% preindustrial (NPP) (% HANPP) remaining for supporting Holocene century- biosphere function mean NPP) Stratospheric Stratospheric O3 10% is found above the materials, including nuclear waste and nuclear weapons; and shallow shelf areas (38) where ecosystems are most intensely ex- human modification of evolution, genetically modified organisms ploited. Regionally, fish catches exceed thresholds of sustainable ex- and other direct human interventions in evolutionary processes. ploitation (39). However, in contrast to land, where most HANPP Novel entities serve as geological markers of the Anthropocene occurs in the form of plant material, i.e., at the lowest trophic level, (5). However, their impacts on Earth system as a whole remain HANPP in the ocean tends to take place at higher trophic levels. largely unstudied. The planetary boundaries framework is only con- This means that while HANPP reduces the absolute amount of cerned with the stability and resilience of Earth system, i.e., not energy available to higher trophic levels on land, much of the human or ecosystem health. Thus, it remains a scientific challenge energy fixed through NPP is used in marine ecosystems before to assess how much loading of novel entities Earth system tolerates HANPP occurs. When the abundance of organisms at the highest before irreversibly shifting into a potentially less habitable state. trophic levels is reduced, changes in marine ecosystem structure Hundreds of thousands of synthetic chemicals are now produced may change energy flow in these ecosystems (40). Thus, in the and released to the environment. For many substances, the poten- marine realm, HANPP likely changes the flows rather than the tially large and persistent effects on Earth system processes of their amount of energy available. More information about the impacts introduction, particularly on functional biosphere integrity, are not of HANPP in the marine realm is necessary to integrate consider- well known, and their use is not well regulated. Humanity has re- ation of the marine systems in the functional biosphere integrity peatedly been surprised by unintended consequences of this release, planetary boundary. e.g., with respect to the release of insecticides such as DDT and the effect of chlorofluorocarbons (CFCs) on the ozone layer. For this Climate change class of novel entities, then, the only truly safe operating space Climate change control variables and boundary levels are retained that can ensure maintained Holocene-like conditions is one (1, 2). The most important drivers of anthropogenic impacts on where these entities are absent unless their potential impacts with Earth’s energy budget are the emission of greenhouse gases and respect to Earth system have been thoroughly evaluated. This would aerosols, and surface albedo changes (17). The control variables imply that the quantified planetary boundary should be set at zero in the framework are the annual averages of atmospheric CO2 release of synthetic chemical compounds to the open environment Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 6 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E unless they have been certified as harmless and are monitored. That Moreover, this boundary now captures Earth system impacts of is the target set by the Montreal Protocol with respect to the sub- both water increases and decreases on a monthly scale and includes stances shown to be harmful by contributing to depletion of the their spatial patterns (see the Supplementary Materials). ozone layer. The control variables describe deviations from the preindustrial In their analysis of various strategies for establishing a planetary (here, 1661–1860) state, first determined at the 30 arc-min grid cell boundary for novel entities, Persson et al. (43) identified the share scale and further aggregated to a global annual value. For both blue of released chemicals with adequate safety assessment and monitor- and green water control variables, boundaries are set at the 95th per- ing as a candidate control variable. We here adopt this metric. The centile of preindustrial variability, i.e., variability of the percentage planetary boundary is then set at the release into Earth system of 0% of global land area with deviations [~10% for blue and ~11% for of untested synthetics. When synthetics released to the environment green water; (46) and the Supplementary Materials]. We assume are thoroughly tested, the ensuing risk of damaging effects is that preindustrial conditions are representative of longer-term Ho- lowered. Admittedly, this approach has weaknesses: Data availabil- locene conditions and that notable deviation from this state puts ity is incomplete; safety studies often focus on narrowly defined tox- freshwater’s Earth system functions at risk. Pending comprehensive icity and do not capture the “cocktail effects” of chemical mixtures assessment of impacts of different transgression levels of the blue in the environment nor their effects under specific conditions. The and green water boundaries (e.g., reduced carbon sequestration ca- Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 percentage of untested synthetics released globally is unknown. pacity, climate regulation, and biodiversity loss; see the Supplemen- However, Persson et al. (43) report that for the chemicals currently tary Materials), the boundary settings are preliminary and highly registered under the EU Registration, Evaluation, Authorisation and precautionary. Currently, ~18% (blue water) and ~16% (green Restriction of Chemicals (REACH) regulation (a small subset of the water) of the global land area experience wet or dry freshwater de- chemical universe), ~80% of these chemicals had been in use for at viations (46). Thus, in contrast to the earlier planetary boundary as- least 10 years without yet having undergone a safety assessment. sessments (1, 2) where only blue water removal was considered, this Likewise, few safety studies consider potential Earth system new approach indicates substantial transgression of the freshwater effects. With such an enormous percentage of untested chemicals change boundary. Transgressions of both the blue and green water being released to the environment, a novel entities boundary boundaries occurred a century ago, in 1905 and 1929, respectively defined in this manner is clearly breached. Persson et al. (43) did (46). Thus, with the revised definition of the control variables, fresh not identify or quantify a singular planetary boundary for novel en- water would have been considered transgressed already at the time tities but, nevertheless, also concluded that the safe operating space of the previous planetary boundary assessments. The previous is currently overstepped. global-scale control variable would still indicate freshwater use to remain in the safe zone, even with newer data sources than those Stratospheric ozone depletion used in (1, 2). Recent estimates of global blue water consumption Stratospheric ozone depletion is a special case related to the anthro- totals ~1700 km3 year−1 (49), i.e., far below the previous boundary pogenic release of novel entities where gaseous halocarbon com- set at 4000 km3 year−1. pounds from industry and other human activities released into the atmosphere lead to long-lasting depletion of Earth’s ozone Atmospheric aerosol loading layer. The boundary for the safe operating space is set at 276 Aerosols have multiple physical, biogeochemical, and biological Dobson units (DU), i.e., allowing a 1.3°C compared to the preindustrial period). Only a small (cumu- ily in plants (86), while only ~6 Gt of C is found in ocean biota (87). lative 25 Gt of C) terrestrial carbon source would have developed by Biologically mediated marine carbon sinks are composed of partic- 2100 and a cumulative source of not >68 Gt of C after 800 years. ulate organic carbon (POC) that can potentially sink below the per- Thus, the exercise suggests that essentially stable planetary condi- manent thermocline (biological pump) and dissolved organic tions would have been maintained had human impacts on these C. Via microbial breakdown of POC and dissolved organic C, two boundaries remained at their 1988 levels, i.e., marginally CO2 is released. When this release influences partial pressure of within the safe operating space. CO2 in surface waters, it tends to reduce oceanic carbon uptake Both of these planetary boundaries have, however, since been from the atmosphere. Microbial respiration is highly sensitive to Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 transgressed into a zone of increasing risk of systemic disruption. temperature and, in a warmer ocean, an increased release of CO2 If climate and land system change can be halted at 450 ppm and in surface waters is predicted (88). The biologically mediated forest cover retained at 60%/30%/60% of boreal/temperate/tropical carbon sink in the ocean most exposed to climate change is the natural cover, then the simulation indicates a mean temperature rise amount of carbon fixed by photosynthesis (NPP), i.e., POC, in over land of 1.4°C by 2100 (in addition to 0.7°C between preindus- the surface ocean that is ultimately transported into the ocean inte- trial time and 1988) and 1.9°C after 800 years as vegetation evolves rior via the biological pump. When this occurs, the resulting carbon in a warmer climate and associated carbon fertilization (Fig. 2). drawdown reduces partial pressure of CO2 in the surface layer and Carbon fertilization of vegetation growth counters the negative tends to increase the atmosphere-to-ocean CO2 flux. impacts of climate warming on the global average carbon sinks, These biological processes are implicitly and, in some cases, ex- leading to only moderate cumulative loss in terrestrial carbon due plicitly included in the CMIP6 models informing the IPCC. to additional deforestation. If, however, deforestation had been However, as these models configure biologically mediated carbon maintained at the level of the planetary boundary rather than flows differently, there is considerable variability in their results. having been allowed to rise in the zone of increasing risk, then Models used by the IPCC do not even agree on the direction of the land biosphere would have developed a cumulative carbon change in NPP in response to climate change (89). Our model sink rather than a source, contributing to stabilizing Earth’s condi- runs (see the Supplementary Materials) suggest no significant tions. In contrast, if deforestation is allowed to breach into the high- change in globally averaged ocean NPP under the different risk zone, then simulations show a substantial additional carbon climate forcing conditions and only a modest decrease in exported leakage to the atmosphere both over the short and long term (132 material out of the surface layer [new production (ΔNP); Table 2]. and 211 Pg of C), despite strong CO2 fertilization of vegetation Using empirical relationships (90, 91) describing the transfer of growth in the model (Fig. 2). carbon to the ocean interior and derived from the contemporary The situation is even more extreme if atmospheric CO2 concen- ocean to estimate biological pump sensitivity to future temperature tration rises above the risk zone (550 ppm; Fig. 2) and deforestation increases indicates a similar weakening of the pump in the upper continues. Not only is the temperature on land about 2.7°C warmer ocean (Table 2 and the Supplementary Materials). That these two than in 1988 (3.4°C warmer than preindustrial), but also around 145 independent methods indicate similar decreases in the export of Gt of C would be lost long-term from terrestrial vegetation and soils. POC from the surface layer lends confidence both in the direction Note that these findings reflect optimistic modeling assumptions on and magnitude of climate impacts on this biologically mediated carbon fertilization. Many of the ecological factors not sufficiently global carbon sink. represented in current biogeochemical models could lead to even The analysis shows that DIC (dissolved inorganic carbon; in- less desirable consequences of leaving the safe operating space. cluding CO2) accumulates over time in the ocean as a whole, par- These simulations illustrate clearly that human impacts on ticularly in the upper ocean (20% (59). Together, these studies suggest that a raised ever to cope with increasing anthropogenic disturbances. There is interhemispheric AOD difference caused by persistent and widely an urgent need for more powerful scientific and policy tools for an- distributed aerosol emissions could lead to major reductions in pre- alyzing the whole of the integrated Earth system with reliability and cipitation in the tropics. regularity and guiding political processes to prevent altering the To examine differing scenarios of transgression of land system state of Earth system beyond levels tolerable for today’s societies. and climate change boundaries, we use the POEM [(85) and the In addition to more consistent collection and collation of relevant Supplementary Materials], which links models of atmospheric Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 11 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E and ocean circulation with models of the marine (BLING) (94) and 14. A. Chrysafi, V. Virkki, M. Jalava, V. Sandström, J. Piipponen, M. Porkka, S. Lade, K. La Mere, L. Wang-Erlandsson, L. Scherer, L. Andersen, E. Bennett, K. Brauman, G. Cooper, A. De terrestrial biosphere (LPJmL5) [(95) and the Supplementary Mate- Palma, P. Döll, A. Downing, T. DuBois, I. Fetzer, E. Fulton, D. Gerten, H. Jaafar, J. Jaegermeyr, rials]. We study scenarios where each of these two planetary boun- F. Jaramillo, M. Jung, H. Kahiluoto, A. Mackay, L. Lassaletta, D. Mason-D’Croz, dary dimensions are either fixed at the value of the boundary, a M. Mekonnen, K. Nash, A. Pastor, N. Ramankutty, B. Ridoutt, S. Siebert, B. Simmons, value in the zone of increasing risk, or a value in the high-risk A. Staal, Z. Sun, A. Tobian, A. Usubiaga-Liaño, R. van der Ent, A. van Soesbergen, zone. Once the respective scenario condition is attained, the associ- P. Verburg, Y. Wada, S. Zipper, M. Kummu, Quantifying Earth system interactions for sustainable food production: An expert elicitation. Nat. Sustain. 5, 830–842 (2022). ated level of scenario forcing remains constant, while the long-term 15. Intergovernmental Panel on Climate Change, Climate Change 2022: Impacts, Adaptation, implications under these fixed conditions evolve. Correspondingly, and Vulnerability, H.-O. Pörtner, D. C. Roberts, M. Tignor, E. S. Poloczanska, K. Mintenbeck, vegetation dynamics (e.g., biome distributions) and related carbon A. Alegría, M. Craig, S. Langsdorf, S. Löschke, V. Möller, A. Okem, B. Rama, Eds. (Cambridge pools and fluxes develop according to biophysical climate interac- Univ. Press, 2022). tions under the given forcing conditions, while biogeochemical 16. E. S. Brondizio, J. Settele, S. Díaz, H. T. Ngo, Global Assessment Report on Biodiversity and Ecosystem Services of the Intergovernmental Science-Policy Platform on Biodiversity and feedbacks on the atmosphere are not considered because of the re- Ecosystem Services (IPBES, 2019). spective boundary or transgression forcing remaining fixed. 17. Intergovernmental Panel on Climate Change, Climate Change 2021: The Physical Science Basis (Cambridge University Press, 2021). 18. D. A. McKay, A. Staal, J. Abrams, R. Winkelmann, B. Sakschewski, S. Loriani, I. Fetzer, Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 Supplementary Materials S. E. Cornell, J. Rockström, T. M. Lenton, Exceeding 1.5°C global warming could trigger This PDF file includes: multiple climate tipping points. Science 377, eabn7950 (2022). Supplementary Information 19. Past Interglacials Working Group of PAGES, Interglacials of the last 800,000 years. Rev. Figs. S1 to S9 Geophys. 54, 162–219 (2016). Tables S1 to S3 20. C. Ragon, V. Lembo, V. Lucarini, C. Vérard, J. Kasparian, M. Brunetti, Robustness of com- References peting climatic states. J. Clim. 35, 2769–2784 (2022). 21. J. M. Anderies, S. R. Carpenter, W. Steffen, J. Rockström, The topology of non-linear global carbon dynamics: From tipping points to planetary boundaries. Environ. Res. Lett. 8, 044048 (2013). REFERENCES AND NOTES 1. J. Rockström, W. Steffen, K. Noone, Å. Persson, S. Chapin, E. F. Lambin, T. M. Lenton, 22. S. J. Lade, J. Norberg, J. Anderies, C. Beer, S. Cornell, J. Donges, I. Fetzer, T. Gasser, M. Scheffer, C. Folke, J. Schellnhuber, B. Nykvist, C. A. DeWit, T. Hughes, S. van der Leeuw, K. Richardson, J. Rockström, W. Steffen, Potential feedbacks between loss of biosphere H. Rodhe, S. Sörlin, P. K. Snyder, R. Costanza, U. Svedin, M. Falkenmark, L. Karlberg, integrity and climate change. Glob. Sust. 2, 1–15 (2019). R. W. Corell, V. J. Fabry, J. Hansen, D. Liverman, K. Richardson, P. Crutzen, J. Foley, A safe 23. M. Exposito-Alonso, T. R. Booker, L. Czech, T. Fukami, L. Gillespie, S. Hateley, C. C. Kyriazis, operating space for humanity. Nature 461, 472–475 (2009). P. L. M. Lang, L. Leventhal, D. Nogues-Bravo, V. Pagowski, M. Ruffley, J. P. Spence, S. E. Toro 2. W. Steffen, K. Richardson, J. Rockström, S. E. Cornell, I. Fetzer, E. M. Bennett, R. Biggs, Arana, C. L. Weiß, E. Zess, Genetic diversity loss in the Anthropocene. Science 377, S. R. Carpenter, W. de Vries, C. A. de Wit, C. Folke, D. Gerten, J. Heinke, G. M. Mace, 1431–1435 (2022). L. M. Persson, V. Ramanathan, B. Reyers, S. Sörlin, Planetary boundaries: Guiding human 24. H. Ceballos, P. R. Ehrlich, A. D. Barnosky, A. García, R. M. Pringle, T. M. Palmer, Accelerated development on a changing planet. Science 347, 1259855 (2015). modern human–induced species losses: Entering the sixth mass extinction. Sci. Adv. 1, 3. W. Steffen, K. Richardson, J. Rockström, H. Schellnhuber, O. P. Dube, S. Dutreil, e1400253 (2015). T. M. Lenton, J. Lubchenco, The emergence and evolution of Earth system science. Nat. 25. M. D. A. Rounsevell, M. Harfoot, P. A. Harrison, T. Newbold, R. D. Gregory, G. M. Mace, A Rev. Earth Environ. 1, 54–63 (2020). biodiversity target based on species extinctions. Science 368, 1193–1195 (2020). 4. J. Zalasiewicz, C. N. Waters, C. Summerhayes, A. P. Wolfe, A. D. Barnosky, A. Cearreta, 26. R. H. Cowie, P. Bouchet, B. Fontaine, The sixth mass extinction: Fact, fiction or speculation? P. Crutzen, E. C. Ellis, J. J. Fairchild, A. Gałuszka, P. Haff, I. Hajdas, M. J. Head, J. A. I. do Sul, Biol. Rev. 97, 640–663 (2022). C. Jeandel, R. Leinfelder, J. R. McNeill, C. Neal, E. Odada, N. Oreskes, W. Steffen, 27. R. J. Scholes, R. Biggs, A Biodiversity Intactness Index. Nature 434, 45–49 (2005). J. P. M. Syvitski, M. Wagreich, M. Williams, The working group on the ‘Anthropocene’: 28. P. A. Martin, R. E. Green, A. Balmford, The Biodiversity Intactness Index may underestimate Summary of evidence and recommendations. Anthropocene 19, 55–60 (2017). losses. Nat. Evol. 3, 862–863 (2019). 5. C. N. Waters, J. Zalasiewicz, C. Summerhayes, A. D. Barnosky, C. Poirier, A. Gałuszka, 29. S. E. Jorgensen, Y. M. Svirezhev, Towards a Thermodynamic Theory for Ecological Systems A. Cearreta, M. Edgeworth, E. C. Ellis, M. Ellis, C. Jeandel, R. Leinfelder, J. R. McNeill, (Elsevier, 2004). D. D. Richter, W. Steffen, J. Syvitski, D. Vidas, M. Wagreich, M. Williams, A. Zhisheng, 30. A. Kleidon, Sustaining the terrestrial biosphere in the anthropocene: A thermodynamic J. Grinevald, E. Odada, N. Oreskes, A. P. Wolfe, The Anthropocene is functionally and Earth system perspective. Ecol. Economy Soc. INSEE J. 6, 53–80 (2023). stratigraphically distinct from the Holocene. Science 351, eaad2622 (2016). 31. S. W. Running, A measurable planetary boundary for the biosphere. Science 337, 6. W. F. Ruddiman, Earth’s Climate: Past and Future (Third edition, W.H. Freeman and 1458–1459 (2012). Co., 2014). 32. H. Haberl, K. H. Erb, F. Krausmann, Human appropriation of net primary production: 7. C. P. Summerhayes, Paleoclimatology: From Snowball Earth to the Anthropocene (Wiley- Patterns, trends, and planetary boundaries. Annu. Rev. Environ. Res. 39, 363–391 (2014). Blackwell, 2020). 33. F. Krausmann, K. H. Erb, S. Gingrich, H. Haberl, A. Bondeau, V. Gaube, C. Lauka, C. Plutzar, 8. H.-J. Schellnhuber, Discourse: Earth system analysis—The scope of the challenge, in Earth T. D. Searchinger, Global human appropriation of net primary production doubled in the System Analysis: Integrating Science for Sustainability. H.-J. Schellnhuber, V. Wenzel, Eds. 20th century. Proc. Natl. Acad. Sci. U.S.A. 110, 10324–10329 (2013). (Springer, Heidelberg, 1998), pp. 3–195. 34. L. V. Gatti, L. S. Basso, J. B. Miller, M. Gloor, L. G. Dominigues, H. L. G. Cassol, G. Tejada, 9. M. B. Osman, J. E. Tierney, J. Zhu, R. Tardif, G. J. Hakim, J. King, C. J. Poulsen, Globally L. E. O. C. Aragao, C. Nobre, W. Peters, L. Marani, E. Arai, A. H. Sanches, S. M. Correa, resolved surface temperatures since the Last Glacial Maximum. Nature 599, L. Anderson, C. Von Randow, C. S. C. Correia, S. P. Crispim, R. A. L. Neves, Amazonia as a 239–244 (2021). carbon source linked to deforestation and climate change. Nature 595, 388–393 (2021). 10. R. M. Beyer, M. Krapp, A. Manica, High-resolution terrestrial climate, bioclimate and 35. K. Goldewijk, A. Beusen, J. Doelman, E. Stehfest, Anthropogenic land use estimates for the vegetation for the last 120,000 years. Sci. Data. 7, 236 (2020). Holocene – HYDE 3.2. Earth Syst. Sci. Data 9, 927–953 (2017). 11. P. K. Snyder, C. Delire, J. A. Foley, Evaluating the influence of different vegetation biomes 36. D. Gerten, V. Heck, J. Jägermeyr, B. L. Bodirsky, I. Fetzer, M. Jalava, M. Kummu, W. Lucht, on the global climate. Clim. Dyn. 23, 279–302 (2004). J. Rockström, S. Schaphoff, H. J. Schellnhuber, Feeding ten billion people is possible 12. P. C. West, G. T. Narisma, C. C. Barford, C. J. Kucharik, J. A. Foley, An alternative approach for within four terrestrial planetary boundaries. Nat. Sust. 3, 200–208 (2020). quantifying climate regulation by ecosystems. Front. Ecol. Environ. 9, 126–133 (2010). 37. S. Ostberg, W. Lucht, S. Schaphoff, D. Gerten, Critical impacts of global warming on land 13. S. J. Lade, W. Steffen, W. de Vries, S. R. Carpenter, J. F. Donges, D. Gerten, H. Hoff, ecosystems. Earth Syst. Dyn. 4, 347–357 (2013). T. Newbold, K. Richardson, J. Rockström, Human impacts on planetary boundaries 38. W. Schwartz, E. Sala, S. Tracey, R. Watson, D. Pauly, The spatial expansion and ecological amplified by Earth system interactions. Nat. Sustain. 3, 119–128 (2020). footprint of fisheries (1950 to present). PLOS ONE 5, e15143 (2010). Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 12 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E 39. J. S. Link, R. A. Watson, Global ecosystem overfishing: Clear delineation within real limits 57. A. Vogel, G. Alessa, R. Scheele, L. Weber, O. Dubovik, P. North, S. Fiedler, Uncertainty in to production. Sci. Adv. 5, eaav047 (2019). aerosol optical depth from modern aerosol-climate models, reanalyses, and satellite 40. B. Planque, J.-M. Fromentin, P. Cury, K. F. Drinkwater, S. Jennings, R. I. Perry, S. Kifani, How products. J. Geophys. Res. Atmos. 127, e2021JD035483 (2022). does fishing alter marine populations and ecosystems sensitivity to climate? J. Mar. Sys. 58. J. Haywood, A. Jones, N. Bellouin, D. Stephenson, Asymmetric forcing from stratospheric 79, 403–417 (2010). aerosols impacts Sahelian rainfall. Nat. Clim. Change. 3, 660–665 (2013). 41. P. M. Forster, C. J. Smith, T. Walsh, W. F. Lamb, M. D. Palmer, K. von Schuckmann, B. Trewin, 59. K. S. Krishnamohan, G. Bala, Sensitivity of tropical monsoon precipitation to the latitude M. Allen, R. Andrew, A. Birt, A. Borger, T. Boyer, J. A. Broersma, L. Cheng, F. Dentener, of stratospheric aerosol injections. Clim. Dyn. 59, 151–168 (2022). P. Friedlingstein, N. Gillett, J. M. Gutiérrez, J. Gütschow, M. Hauser, B. Hall, M. Ishii, 60. S. Roose, G. Bala, K. S. Krishnamohan, L. Cao, K. Caldeira, Quantification of tropical S. Jenkins, R. Lamboll, X. Lan, J.-Y. Lee, C. Morice, C. Kadow, J. Kennedy, R. Killick, J. Minx, monsoon precipitation changes in terms of interhemispheric differences in stratospheric V. Naik, G. Peters, A. Pirani, J. Pongratz, A. Ribes, J. Rogelj, D. Rosen, C.-F. Schleussner, sulfate aerosol optical depth. Clim. Dyn. 2023, 1–16 (2023). S. Seneviratne, S. Szopa, P. Thorne, R. Rohde, M. Rojas Corradi, D. Schumacher, R. Vose, 61. A. Donohoe, J. Marshall, D. Ferreira, D. Mcgee, The relationship between ITCZ location K. Zickfeld, X. Zhang, V. Masson-Delmotte, P. Zhai, Indicators of Global Climate Change and cross-equatorial atmospheric heat transport: From the seasonal cycle to the last 2022: Annual update of large-scale indicators of the state of the climate system and the glacial maximum. J. Clim. 26, 3597–3618 (2013). human influence. Earth Syst. Sci. Data 15, 2295–2327 (2023). 62. M. C. MacCracken, H.-J. Shin, K. Caldeira, G. A. Ban-Weiss, Climate response to imposed 42. H. Schellnhuber, S. Rahmstorf, R. Winkelmann, Why the right climate target was agreed in solar radiation reductions in high latitudes. Earth Syst. Dyn. 4, 301–315 (2013). Paris. Nat. Clim. Change 6, 649–653 (2016). 63. N. Devaraju, G. Bala, A. Modak, Effects of large-scale deforestation on precipitation in the 43. L. Persson, B. Almroth, C. Collins, S. Cornell, C. de Wit, M. Diamond, P. Fantke, M. Hassellöv, monsoon regions: Remote versus local effects. Proc. Natl. Acad. Sci. U.S.A. 112, M. MacLeod, M. Ryberg, P. Jørgensen, P. Villarrubia-Gómez, Z. Wang, M. Zwicky Hauschild, 3257–3262 (2015). Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 Outside the safe operating space of the planetary boundary for novel entities. Environ. Sci. 64. I. B. Ocko, V. Ramaswamy, Y. Ming, Contrasting climate responses to the scattering and Tech. 56, 1510–1521 (2022). absorbing features of anthropogenic aerosol forcings. J. Clim. 27, 5329–5345 (2014). 44. P. J. Nair, L. Froidevaux, J. Kuttippurath, J. M. Zawodny, J. M. Russell III, W. Steinbrecht, 65. M. Zhao, L. Cao, G. Bala, L. Duan, Climate response to latitudinal and altitudinal distri- H. Claude, T. Leblanc, J. A. E. van Gijsel, B. Johnson, D. P. J. Swart, A. Thomas, R. Querel, bution of stratospheric sulfate aerosols. J. Geophys. Res. Atmos. 126, R. Wang, J. Anderson, Subtropical and midlatitude ozone trends in the stratosphere: e2021JD035379 (2021). Implications for recovery. J. Geophys. Res. Atmos. 120, 7247–7257 (2015). 66. J. T. Fasullo, B. L. Otto-Bliesner, S. Stevenson, The influence of volcanic aerosol meridional 45. A. Pazmiño, S. Godin-Beekmann, A. Hauchecorne, C. Claud, S. Khaykin, F. Goutail, structure on monsoon responses over the last millennium. Geophys. Res. Lett. 46, E. Wolfram, J. Salvador, E. Quel, Multiple symptoms of total ozone recovery inside the 12350–12359 (2019). Antarctic vortex during austral spring. Atmospheric Chem. Phys. 18, 7557–7572 (2018). 67. S. Fiedler, T. Crueger, R. D’Agostino, K. Peters, T. Becker, D. Leutwyler, L. Paccini, 46. M. Porkka, V. Virkki, L. Wang-Erlandsson, D. Gerten, T. Gleeson, C. Mohan, I. Fetzer, J. Burdanowitz, S. Buehler, A. Uribe, T. Dauhut, D. Dommenget, K. Fraedrich, F. Jaramillo, A. Staal, S. te Wierik, A. Tobian, R. van der Ent, P. Döll, M. Flörke, S. N. Gosling, L. Jungandreas, N. Maher, A. Naumann, M. Rugenstein, M. Sakradzija, H. Schmidt, N. Hanasaki, Y. Satoh, H. M. Schmied, N. Wanders, J. Rockström, M. Kummu, Global water F. Sielmann, C. Stephan, C. Timmreck, X. Zhu, B. Stevens, Simulated tropical precipitation cycle shifts far beyond pre-industrial conditions – Planetary boundary for freshwater assessed across three major phases of the Coupled Model Intercomparison Project (CMIP). change transgressed (2023); https://eartharxiv.org/repository/view/3438/. Mon. Weather Rev. 148, 3653–3680 (2020). 47. T. Gleeson, L. Wang-Erlandsson, S. C. Zipper, M. Porkka, F. Jaramillo, D. Gerten, I. Fetzer, 68. P. Zanis, D. Akritidis, A. K. Georgoulias, R. J. Allen, S. E. Bauer, O. Boucher, J. Cole, S. E. Cornell, L. Piemontese, L. J. Gordon, J. Rockström, T. Oki, M. Sivapalan, Y. Wada, B. Johnson, M. Deushi, M. Michou, J. Mulcahy, P. Nabat, D. Olivié, N. Oshima, A. Sima, K. A. Brauman, M. Flörke, M. F. P. Bierkens, B. Lehner, P. Keys, M. Kummu, T. Wagener, M. Schulz, T. Takemura, K. Tsigaridis, Fast responses on pre-industrial climate from S. Dadson, T. J. Troy, W. Steffen, M. Falkenmark, J. S. Famiglietti, The water planetary present-day aerosols in a CMIP6 multi-model study. Atmos. Chem. Phys. 20, boundary: Interrogation and revision. One Earth. 2, 223–234 (2020). 8381–8404 (2020). 48. L. Wang-Erlandsson, A. Tobian, R. J. van der Ent, I. Fetzer, S. te Wierik, M. Porkka, A. Staal, 69. S. Fiedler, B. Stevens, M. Gidden, S. J. Smith, K. Riahi, D. van Vuuren, First forcing estimates F. Jaramillo, H. Dahlmann, C. Singh, P. Greve, D. Gerten, P. W. Keys, T. Gleeson, S. E. Cornell, from the future CMIP6 scenarios of anthropogenic aerosol optical properties and an as- W. Steffen, X. Bai, J. Rockström, A planetary boundary for green water. Nat. Rev. Earth sociated Twomey effect. Geosci. Model Dev. 12, 989–1007 (2019). Environ. 3, 380–392 (2022). 70. N. M. Mahowald, R. Scanza, J. Brahney, C. L. Goodale, P. G. Hess, J. K. Moore, J. Neff, Aerosol 49. Y. Qin, N. D. Mueller, S. Siebert, R. B. Jackson, A. A. Kouchak, J. B. Zimmerman, D. Tong, deposition impacts on land and ocean carbon cycles. Curr. Clim. Change Rep. 3, C. Hong, S. J. Davis, Flexibility and intensity of global water use. Nat. Sustain. 2, 16–31 (2017). 515–523 (2019). 71. L. Jiang, R. A. Feely, B. R. Carter, D. J. Greeley, D. K. Gledhill, K. M. Arzayus, Climatological 50. K. S. Carslaw, H. Gordon, D. S. Hamilton, J. S. Johnson, L. A. Regayre, M. Yoshioka, distribution of aragonite saturation state in the global oceans. Glob. Biogeochem. Cycles. K. J. Pringle, Aerosols in the pre-industrial atmosphere. Curr. Clim. Chang. Rep. 3, 29, 1656–1673 (2015). 1–15 (2017). 72. EU Copernicus Climate Change Service, “Land cover classification gridded maps from 51. N. Bellouin, J. Quaas, E. Gryspeerdt, S. Kinne, P. Stier, D. Watson-Parris, O. Boucher, 1992 to present derived from satellite observations”, ICDR Land Cover 2016–2020. K. S. Carslaw, M. Christensen, A.-L. Daniau, J.-L. Dufresne, G. Feingold, S. Fiedler, P. Forster, 73. Food and Agricultural Organization of the United Nations, (FAO), United Nations’ Envi- A. Gettelman, J. M. Haywood, U. Lohmann, F. Malavelle, T. Mauritsen, D. T. McCoy, ronmental Program, (UNEP), “The State of the World’s Forests 2020. Forests, biodiversity G. Myhre, J. Mülmenstädt, D. Neubauer, A. Possner, M. Rugenstein, Y. Sato, M. Schulz, and people” (Publication 978-92-5-132419-6, 2020); https://doi.org/10.4060/ca8642en. S. E. Schwartz, O. Sourdeval, T. Storelvmo, V. Toll, D. Winker, B. Stevens, Bounding global 74. Food and Agricultural Organization of the United Nations, (FOA), “Global Forest Resources aerosol radiative forcing of climate change. Rev. Geophys. 58, e2019RG000660 (2020). Assessment 2020: Main report” (Publication 978-92-5-132974-0, 2020); https://doi.org/10. 52. J. Hooper, S. K. Marx, A global doubling of dust emissions during the Anthropocene? 4060/ca9825en. Glob. Planet. Change 169, 70–91 (2018). 75. S. R. Carpenter, E. M. Bennett, Reconsideration of the planetary boundary for phosphorus. 53. P. Kinppertz, M. C. Todd, Mineral dust aerosols over the Sahara: Meteorological controls Environ. Res. Lett. 6, 014009 (2011). on emission and transport and implications for modeling. Rev. Geophys. 50, 76. C. Liu, H. Tian, Global nitrogen and phosphorus fertilizer use for agriculture production in RG1007 (2012). the past half century: Shifted hot spots and nutrient imbalance. Earth Syst. Sci. Data 9, 54. M. L. Griffiths, K. R. Johnson, F. S. R. Pausata, J. C. White, G. M. Henderson, C. T. Wood, 181–192 (2017). H. Yang, V. Ersek, C. Conrad, N. Sekhon, End of Green Sahara amplified mid- to late Ho- 77. W. J. Brownlie, M. A. Sutton, K. V. Heal, D. S. Reay, B. M. Spears (eds.), Our Phosphorus Future locene megadroughts in mainland Southeast Asia. Nat. Commun. 11, 4204 (2020). (U.K. Centre for Ecology & Hydrology, 2022). 55. M. Chin, T. Diehl, Q. Tan, J. M. Prospero, R. A. Kahn, L. A. Remer, H. Yu, A. M. Sayer, H. Bian, 78. T. Zou, X. Zhang, E. Davidson, Improving phosphorus use efficiency in cropland to I. V. Geogdzhayev, B. N. Holben, S. G. Howell, B. J. Huebert, N. C. Hsu, D. Kim, T. L. Kucsera, address phosphorus challenges by 2050. Earth Space Sci. Open Archive, (2020). https://doi. R. C. Levy, M. I. Mishchenko, X. Pan, P. K. Quinn, G. L. Schuster, D. G. Streets, S. A. Strode, org/10.1002/essoar.10504095.1 O. Torres, X.-P. Zhao, Multi-decadal aerosol variations from 1980 to 2009: A perspective from observations and a global model. Atmos. Chem. Phys. 14, 3657–3690 (2014). 79. D. Cordell, S. White, Life’s bottleneck: Sustaining the World’s phosphorus for a food secure future. Annu. Rev. Environ. Res. 39, 161–188 (2014). 56. L. Sogacheva, T. Popp, A. M. Sayer, O. Dubovik, M. J. Garay, A. Heckel, N. C. Hsu, H. Jethva, R. A. Kahn, P. Kolmonen, M. Kosmale, G. de Leeuw, R. C. Levy, P. Litvinov, A. Lyapustin, 80. Food and Agriculture Organisation of the United Nations (FAO), “World fertilizer trends P. North, O. Torres, Merging regional and global AOD records from 15 available satellite and outlook to 2022 – Summary Report, Rome” (2019); www.fao.org/3/ca6746en/ products. Atmos. Chem. Phys. 20, 2031–2056 (2019). ca6746en.pdf ) Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 13 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E 81. M. A. Adams, N. Buchmann, J. Sprent, T. N. Buckley, T. L. Turnbull, Crops, nitrogen, water: 106. S. Theodoridis, D. A. Fordham, S. C. Brown, S. Li, C. Rahbek, D. Nogues-Bravo, Evolutionary Are legumes friend, foe, or misunderstood ally? Trends Plant. Sci. 23, 539–550 (2018). history and past climate change shape the distribution of genetic diversity in terrestrial 82. P. M. Vitousek, D. N. L. Menge, S. C. Reed, C. C. Cleveland, Biological nitrogen fixation: mammals. Nat. Commun. 11, 2557 (2020). Rates, patterns and ecological controls in terrestrial ecosystems. Philos. Trans. R. Soc. Lond. 107. D. M. Leigh, C. B. van Rees, K. L. Millette, M. F. Breed, C. Schmidt, L. D. Bertola, B. K. Hand, B. Biol. Sci. 368, 1621 (2013). M. E. Hunter, E. L. Jensen, F. Kershaw, L. Liggins, G. Luikart, S. Manel, J. Mergeay, J. M. Miller, 83. M. V. B. Figueiredo, A. E. S. Mergulhão, J. K. Sobral, M. A. L. Junio, A. S. F. Araújo, Biological G. Segelbacher, S. Hoban, I. Paz-Vinas, Opportunities and challenges of macrogenetic nitrogen fixation: Importance, associated diversity, and estimates, in Plant Microbe Sym- studies. Nat. Rev. Genet. 22, 791–807 (2021). biosis: Fundamentals and Advances (Springer, 2013), pp. 267–289. 108. S. Theodoridis, C. Rahbek, D. Nogués-Bravo, Exposure of mammal genetic diversity to 84. FAO, “FAOSTAT—FAO database for food and agriculture” (2022); www.fao.org/faostat/ mid-21st century global change. Ecography 44, 817–831 (2021). (accessed 4.19.22) 109. S. Hoban, M. Brufordb, J. D’Urban Jackson, M. Lopes-Fernandes, M. Heuertz, 85. M. Drüke, W. von Bloh, S. Petri, B. Sakschewski, S. Schaphoff, M. Forkel, W. Huiskamp, P. A. Hohenlohe, I. Paz-Vinas, P. Sjögren-Gulve, G. Segelbacher, C. Vernesi, S. Aitken, G. Feulner, K. Thonicke, CM2Mc-LPJmL v1.0: Biophysical coupling of a process-based L. D. Bertola, P. Bloomer, M. Breed, H. Rodríguez-Correa, W. C. Funk, C. E. Grueber, dynamic vegetation model with managed land to a general circulation model. Geosci. M. E. Hunter, L. Laikre, Genetic diversity targets and indicators in the CBD post-2020 Model. Dev. 14, 4117–4141 (2021). global biodiversity framework must be improved. Biol. Conserv. 248, 108654 (2020). 86. K.-H. Erb, T. Kastner, C. Plutzar, A. L. S. Bais, N. Carvalhais, T. Fetzel, S. Gingrich, H. Haberl, 110. A. Ganopolski, V. Brovkin, Simulation of climate, ice sheets and CO2 evolution during the C. Lauk, M. Niedertscheider, J. Pongratz, M. Thurner, S. Luyssaert, Unexpectedly large last four glacial cycles with an Earth system model of intermediate complexity. Clim. 13, impact of forest management and grazing on global vegetation biomass. Nature 553, 1695–1716 (2017). 73–76 (2017). 111. S. Schaphoff, W. Bloh, A. Rammig, K. Thonicke, H. Biemans, M. Forkel, D. Gerten, J. Heinke, Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 87. Y. M. Bar-On, R. Phillips, R. Milo, The biomass distribution on Earth. Proc. Natl. Acad. Sci. J. Jägermeyr, J. Knauer, F. Langerwisch, W. Lucht, C. Müller, S. Rolinski, K. Waha, LPJmL4–a U.S.A. 115, 6506–6511 (2018). dynamic global vegetation model with managed land – Part 1: Model description. Geosci. 88. K. Matsuomoto, T. Hashioka, Y. Yamanaka, Effect of temperature-dependent organic Model Dev. 11, 1343–1375 (2018). carbon decay on atmospheric pCO2. J. Geophys. Res. 112, G02007 (2007). 112. I. C. Harris, P. D. Jones, “CRU TS3.23: Climatic Research Unit (CRU) Time-Series (TS) Version 89. L. Kwiatkowski, O. Torres, L. Bopp, O. Aumont, M. Chamberlain, J. R. Christian, J. P. Dunne, 3.23 of High Resolution Gridded Data of Month-by-month Variation in Climate (Jan. 1901- M. Gehlen, T. Ilyina, J. G. John, A. Lenton, H. Li, N. S. Lovenduski, J. C. Orr, J. Palmieri, Dec. 2014)” (CEDA Archive, 2015); https://catalogue.ceda.ac.uk/uuid/ Y. Santana-Falcón, J. Schwinger, R. Séférian, C. A. Stock, A. Tagliabue, Y. Takano, J. Tjiputra, 5dca9487dc614711a3a933e44a933ad3 K. Toyama, H. Tsujino, M. Watanabe, A. Yamamoto, A. Yool, T. Ziehn, Twenty-first century 113. I. Harris, P. Jones, T. Osborn, D. Lister, Updated high-resolution grids of monthly climatic ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary observations – The CRU TS3.10 dataset. Int. J. Climatol. 34, 623–642 (2014). production decline from CMIP6 model projections. Biogeosci 17, 3439–3470 (2020). 114. D. Kaufman, N. McKay, C. Routson, M. Erb, C. Dätwyler, P. S. Sommer, O. Heiri, B. Davis, 90. E. A. Laws, E. D’Sa, P. Naik, Simple equations to estimate ratios of new or export pro- Holocene global mean surface temperature, a multi-method reconstruction approach. duction to total production from satellite-derived estimates of sea surface temperature Sci. Data 7, 201 (2020). and primary production. Limnol. Oceanogr. Meth. 9, 593–601 (2011). 115. H. Haberl, K. H. Erb, F. Krausmann, V. Gaube, A. Bondeau, C. Plutzar, S. Gingrich, W. Lucht, 91. C. M. Marsay, R. J. Sanders, S. A. Henson, K. Pabortsava, E. P. Achterberg, R. S. Lampitt, M. Fischer-Kowalski, Quantifying and mapping the human appropriation of net primary Attenuation of sinking POC flux in the mesopelagic. Proc. Natl. Acad. Sci. U.S.A. 112, production in Earth’s terrestrial ecosystems. Proc. Natl. Acad. Sci. U.S.A. 104, 1089–1094 (2015). 12942–12947 (2007). 92. K. A. Chrichton, J. D. Wilson, A. Ridgewell, F. Boscob-Galazzo, E. H. John, B. S. Wade, 116. D. Lawrence, K. Vandecar, Effects of tropical deforestation on climate and agriculture. Nat. P. N. Pearson, What the geological past can tell us about the future of the ocean’s twilight Clim. Change 5, 27–36 (2015). zone. Nat. Commun. 14, 2376 (2023). 117. P. W. Keys, L. Wang-Erlandsson, L. J. Gordon, Revealing invisible water: Moisture recycling 93. The Royal Society, “Ocean acidification due to increasing atmospheric carbon dioxide” as an ecosystem service. PLOS ONE 11, e0151993 (2016). (Publication 0 85403 617 2, Policy Doc. 12/05, R. Soc., 2005). 118. L. Wang-Erlandsson, I. Fetzer, P. W. Keys, R. J. van der Ent, H. H. G. Savenije, L. J. Gordon, 94. E. D. Galbraith, J. P. Dunne, A. Gnanadesikan, R. D. Slater, J. L. Sarmiento, C. O. Dufour, Remote land use impacts on river flows through atmospheric teleconnections. Hydrol. G. F. de Souza, D. Bianchi, M. Claret, K. B. Rodgers, S. S. Marvasti, Complex functionality Earth Syst. Sci. 22, 4311–4328 (2018). with minimal computation: Promise and pitfalls of reduced-tracer ocean biogeochemistry 119. D. Gerten, H. Hoff, J. Rockström, J. Jägermeyr, M. Kummu, A. V. Pastor, Towards a revised models. J. Adv. Model Earth Syst. 7, 2012–2028 (2015). planetary boundary for consumptive freshwater use: Role of environmental flow re- 95. S. Schaphoff, M. Forkel, C. Müller, J. Knauer, W. von Bloh, D. Gerten, J. Jägermeyr, W. Lucht, quirements. Curr. Opin. Environ. Sustain. 5, 551–558 (2013). A. Rammig, K. Thonicke, K. Waha, LPJmL4 – A dynamic global vegetation model with 120. J. Liu, C. Zang, S. Tian, J. Liu, H. Yang, S. Jia, L. You, B. Liu, M. Zhang, Water conservancy managed land – Part 2: Model evaluation. Geosci. Model Dev. 11, 1377–1403 (2018b). projects in China: Achievements, challenges and way forward. Glob. Environ. Change 23, 96. NASA Earth Observation, “AURA Ozone data”; https://neo.gsfc.nasa.gov/archive/geotiff. 633–643 (2013). float/AURA_OZONE_M/. 121. J. Sillmann, C. W. Stjern, G. Myhre, B. H. Samset, Ø. Hodnebrog, T. Andrews, O. Boucher, 97. N. Ramankutty, J. A. Foley, Characterizing patterns of global land use: An analysis of G. Faluvegi, P. Forster, M. R. Kasoar, V. V. Kharin, A. Kirkevåg, J.-F. Lamarque, D. J. L. Olivié, global croplands data. Glob. Biogeochem. Cycles. 12, 667–685 (1998). T. B. Richardson, D. Shindell, T. Takemura, A. Voulgarakis, F. W. Zwiers, Extreme wet and 98. C. W. Snyder, M. D. Mastrandrea, S. H. Schneider, The complex dynamics of the climate dry conditions affected differently by greenhouse gases and aerosols. Nat. Clim. Atmo- system: Constraints on our knowledge, policy implications and the necessity of systems spheric Sci. 2, 1–7 (2019). thinking. Philos. Complex Syst. 10, 467–505 (2011). 122. N. L. Poff, J. D. Olden, D. M. Merritt, D. M. Pepin, Homogenization of regional river dy- 99. M. Willeit, A. Ganopolski, R. Calov, V. Brovkin, Mid-Pleistocene transition in glacial cycles namics by dams and global biodiversity implications. Proc. Natl. Acad. Sci. U.S.A. 104, explained by declining CO2 and regolith removal. Sci. Adv. 5, eaav7337 (2019). 5732–5737 (2007). 100. J. Zheng, J. L. Payne, A. Wagner, Cryptic genetic variation accelerates evolution by 123. A. Staal, O. A. Tuinenburg, J. H. C. Bosmans, M. Holmgren, E. H. van Nes, M. Scheffer, opening access to diverse adaptive peaks. Science 365, 347–353 (2019). D. C. Zemp, S. C. Dekker, Forest-rainfall cascades buffer against drought across the 101. M. C. Bitter, L. Kapsenberg, J.-P. Gattuso, C. A. Pfister, Standing genetic variation fuels Amazon. Nat. Clim. Change 8, 539–543 (2018). rapid adaptation to ocean acidification. Nat. Commun. 10, 5821 (2019). 124. A. Günther, A. Barthelmes, V. Huth, H. Joosten, G. Jurasinski, F. Koebsch, J. Couwenberg, 102. T. H. Oliver, M. S. Heard, N. J. Isaac, D. B. Roy, D. Procter, F. Eigenbrod, R. Freckleton, Prompt rewetting of drained peatlands reduces climate warming despite methane A. Hector, C. D. L. Orme, O. L. Petchey, V. Proença, Biodiversity and resilience of ecosystem emissions. Nat. Commun. 11, 1644 (2020). functions. Trends Ecol. Evol. 30, 673–684 (2015). 125. T. Maavara, Q. Chen, K. Van Meter, L. E. Brown, J. Zhang, J. Ni, C. Zarfl, River dam impacts 103. A. A. Hoffmann, C. M. Sgrò, T. N. Kristensen, Revisiting adaptive potential, population size, on biogeochemical cycling. Nat. Rev. Earth Environ. 1, 103–116 (2020). and conservation. Trends Ecol. Evol. 32, 506–517 (2017). 126. N. Boers, N. Marwan, H. M. J. Barbosa, J. Kurths, A deforestation-induced tipping point for 104. A. Miraldo, S. Li, M. K. Borregaard, A. Flórez-Rodríguez, S. Gopalakrishnan, M. Rizvanovic, the south American monsoon system. Sci. Rep. 7, 41489 (2017). Z. Wang, C. Rahbek, K. A. Marske, D. Nogués-Bravo, An anthropocene map of genetic 127. K. Frieler, S. Lange, F. Piontek, C. P. O. Reyer, J. Schewe, L. Warszawski, F. Zhao, L. Chini, diversity. Science 353, 1532–1535 (2016). S. Denvil, K. Emanuel, T. Geiger, K. Halladay, G. Hurtt, M. Mengel, D. Murakami, S. Ostberg, 105. S. Blanchet, J. G. Prunier, H. De Kort, Time to go bigger: Emerging patterns in macro- A. Popp, R. Riva, M. Stevanovic, T. Suzuki, J. Volkholz, E. Burke, P. Ciais, K. Ebi, T. D. Eddy, genetics. Trends Genet. 33, 579–580 (2017). J. Elliott, E. Galbraith, S. N. Gosling, F. Hattermann, T. Hickler, J. Hinkel, C. Hof, V. Huber, Richardson et al., Sci. Adv. 9, eadh2458 (2023) 13 September 2023 14 of 16 S C I E N C E A D VA N C E S | R E S E A R C H A R T I C L E J. Jägermeyr, V. Krysanova, R. Marcé, H. Müller Schmied, I. Mouratiadou, D. Pierson, 149. B. Zhuang, Y. Gao, Y. Hu, H. Chen, T. Wang, S. Li, M. Li, M. Xie, Interaction between different D. P. Tittensor, R. Vautard, M. van Vliet, M. F. Biber, R. A. Betts, B. L. Bodirsky, D. Deryng, mixing aerosol direct effects and East Asian summer monsoon. Clim. Dyn. 61, S. Frolking, C. D. Jones, H. K. Lotze, H. Lotze-Campen, R. Sahajpal, K. Thonicke, H. Tian, 1157–1176 (2022). Y. Yamagata, Assessing the impacts of 1.5 °C global warming – Simulation protocol of the 150. D. M. Westervelt, Y. You, X. Li, M. Ting, D. E. Lee, Y. Ming, Relative importance of green- Inter-Sectoral Impact Model Intercomparison Project (ISIMIP2b). Geosci. Model Dev. 10, house gases, sulfate, organic carbon, and black carbon aerosol for south asian monsoon 4321–4345 (2017). rainfall changes. Geophys. Res. Lett. 47, e2020GL088363 (2020). 128. S. Siebert, M. Kummu, M. Porkka, P. Döll, N. Ramankutty, B. R. Scanlon, A global data set of 151. E. D. Galbraith, E. Y. Kwon, A. Gnanadesikan, K. B. Rodgers, S. M. Griffies, D. Bianchi, the extent of irrigated land from 1900 to 2005. Hydrol. Earth Syst. Sci. 19, J. L. Sarmiento, J. P. Dunne, J. Simeon, R. D. Slater, A. T. Wittenberg, I. M. Held, Climate 1521–1545 (2015). variability and radiocarbon in the CM2Mc Earth system model. J. Clim. 24, 129. Y. Wada, M. F. P. Bierkens, Sustainability of global water use: Past reconstruction and 4230–4254 (2011). future projections. Environ. Res. Lett. 9, 104003 (2014). 152. W. von Bloh, S. Schaphoff, C. Müller, S. Rolinski, K. Waha, S. Zaehle, Implementing the 130. C. Zarfl, A. E. Lumsdon, J. Berlekamp, L. Tydecks, K. Tockner, A global boom in hydropower nitrogen cycle into the dynamic global vegetation, hydrology, and crop growth model dam construction. Aquat. Sci. 77, 161–170 (2015). LPJmL (version 5.0). Geosci. Model Dev. 11, 2789–2812 (2018). 131. R. J. Keenan, G. A. Reams, F. Achard, J. V. de Freitas, A. Grainger, E. Lindquist, Dynamics of 153. P. C. D. Milly, A. B. Shmakin, Global modeling of land water and energy balances. Part I: global forest area: Results from the FAO Global Forest Resources Assessment 2015. For. The land dynamics (LaD) model. J. Hydrometeorol. 3, 283–299 (2002). Ecol. Manag. 352, 9–20 (2015). 154. J. L. Anderson, V. Balaji, A. J. Broccoli, W. F. Cooke, T. L. Delworth, K. W. Dixon, L. J. Donner, 132. A. Barnosky, E. Hadly, J. Bascompte, E. L. Berlow, J. H. Brown, M. Fortelius, W. M. Getz, K. A. Dunne, S. M. Freidenreich, S. T. Garner, R. G. Gudgel, C. T. Gordon, I. M. Held, J. Harte, A. Hastings, P. A. Marquet, N. D. Martinez, A. Mooers, P. Roopnarine, G. Vermij, R. S. Hemler, L. W. Horowitz, S. A. Klein, T. R. Knutson, P. J. Kushner, A. R. Langenhost, Downloaded from https://www.science.org at University Van Amsterdam on November 01, 2023 J. W. Williams, R. Gillespie, J. Kitzes, C. Marshall, N. Matzke, D. P. Mindell, E. Revilla, N. C. Lau, Z. Liang, S. L. Malyshev, P. C. D. Milly, M. J. Nath, J. J. Ploshay, V. Ramaswamy, A. B. Smith, Approaching a state shift in Earth’s biosphere. Nature 486, 52–58 (2012). M. D. Schwarzkopf, E. Shevliakova, J. J. Sirutis, B. J. Soden, W. F. Stern, L. A. Thompson, 133. H. J. Fowler, G. Lenderink, A. F. Prein, S. Westra, R. P. Allan, N. Ban, R. Barbero, P. Berg, R. J. Wilson, A. T. Wittenberg, B. L. Wyman, The new GFDL global atmosphere and land S. Blenkinsop, H. X. Do, S. Guerreiro, J. O. Haerter, E. J. Kendon, E. Lewis, C. Schaer, model AM2-LM2: Evaluationvwith prescribed SST simulations. J. Clim. 17, A. Sharma, G. Villarini, C. Wasko, X. Zhang, Anthropogenic intensification of short-dura- 4641–4673 (2004). tion rainfall extremes. Nat. Rev. Earth Environ. 2, 107–122 (2021). 155. S. Sitch, B. Smith, I. C. Prentice, A. Arneth, A. Bondeau, W. Cramer, J. O. Kaplan, S. Levis, 134. L. Gudmundsson, J. Boulange, H. X. Do, S. N. Gosling, M. G. Grillakis, A. G. Koutroulis, W. Lucht, M. T. Sykes, K. Thonicke, S. Venevsky, Evaluation of ecosystem dynamics, plant M. Leonard, J. Liu, N. M. Schmied, L. Papadimitriou, Y. Pokhrel, S. I. Seneviratne, Y. Satoh, geography and terrestrial carbon cycling in the LPJ dynamic global vegetation model. W. Thiery, S. Westra, X. Zhang, F. Zhao, Globally observed trends in mean and extreme Glob. Change Biol. 9, 161–185 (2003). river flow attributed to climate change. Science 371, 1159–1162 (2021). 156. D. Gerten, S. Schaphoff, U. Haberlandt, W. Lucht, S. Sitch, Terrestrial vegetation and large- 135. J. Spinoni, G. Naumann, H. Carrao, P. Barbosa, J. Vogt, World drought frequency, duration, scale water balance. Hydrological evaluation of a dynamic global vegetation model. and severity for 1951–2010. Int. J. Climatol. 34, 2792–2804 (2014). J. Hydrol. 286, 249–270 (2004). 136. T. G. Huntington, Evidence for intensification of the global water cycle: Review and 157. A. Bondeau, P. Smith, S. Zaehle, S. Schaphoff, W. Lucht, W. Cramer, D. Gerten, H. Lotze- synthesis. J. Hydrol. 319, 83–95 (2006). Campen, C. Müller, M. Reichstein, B. Smith, Modelling the role of agriculture for the 20th 137. J. Jägermeyr, A. Pastor, H. Biemans, D. Gerten, Reconciling irrigated food production with century global terrestrial carbon balance. Glob. Change Biol. 13, 1–28 (2007). environmental flows for sustainable development goals implementation. Nat. Commun. 158. K. Thonicke, A. Spessa, I. C. Prentice, S. P. Harrison, L. Dong, C. Carmona-Moreno, The 8, 15900 (2017). influence of vegetation, fire spread and fire behaviour on biomass burning and trace gas 138. A. V. Pastor, F. Ludwig, H. Biemans, H. Hoff, P. Kabat, Accounting for environmental flow emissions: Results from a process-based model. Biogeosci. 7, 1991–2011 (2010). requirements in global water assessments. Hydrol. Earth Syst. Sci. 18, 5041–5059 (2014). 159. M. Drüke, M. Forkel, W. von Bloh, B. Sakschewski, M. Cardoso, M. Bustamante, J. Kurths, 139. V. Virkki, E. Alanärä, M. Porkka, L. Ahopelto, T. Gleeson, C. Mohan, L. Wang-Erlandsson, K. Thonicke, Improving the LPJmL4-SPITFIRE vegetation-fire model for South America M. Flörke, D. Gerten, S. N. Gosling, N. Hanasaki, H. Müller Schmied, N. Wanders, M. Kummu, using satellite data. Geosci. Model. Dev. 12, 5029–2054 (2019). Globally widespread and increasing violations of environmental flow envelopes. Hydrol. 160. M. Forkel, N. Carvalhais, S. Schaphoff, W. von Bloh, M. Migliavacca, M. Thurner, K. Thonicke, Earth Syst. Sci. 26, 3315–3336 (2022). Identifying environmental controls on vegetation greeness phenology through model- 140. P. Greve, B. Orlowsky, B. Mueller, J. Sheffield, M. Reichstein, S. I. Seneviratne, Global as- data integration. Biogeosci. 11, 7025–7050 (2014). sessment of trends in wetting and drying over land. Nat. Geosci. 7, 716–721 (2014). 161. M. Forkel, M. Drüke, M. Thurner, W. Dorigo, S. Schaphoff, K. Thonicke, W. von Bloh, 141. P. Micklin, The aral sea disaster. Annu. Rev. Earth Planet. Sci. 35, 47–72 (2018). N. Carvalhais, Constraining modelled global vegetation dynamics and carbon turnover 142. W. M. Hammond, A. P. Williams, J. T. Abatzoglou, H. D. Adams, T. Klein, R. López, C. Sáenz- using multiple satellite observations. Sci. Rep. 9, 18757 (2019). Romero, H. Hartmann, D. D. Breshears, C. D. Allen, Global field observations of tree die-off 162. S. Fader, C. Rost, A. Müller, D. Bondeau, Gerten, virtual water content of temperate cereals reveal hotter-drought fingerprint for Earth’s forests. Nat. Commun. 13, 1761 (2022). and maize: Present and potential future patterns. J. Hydrol. 384, 218–231 (2010). 143. R. S. Cottrell, K. L. Nash, B. S. Halpern, T. A. Remenyi, S. P. Corney, A. Fleming, E. A. Fulton, 163. V. Kattsov, R. Federation, C. Reason, S. Africa, A. A. Uk, T. A. Uk, J. Baehr, A. B. Uk, J. Catto, S. Hornborg, A. Johne, R. A. Watson, J. L. Bla