| 1. |
- Chrysafi, Anna, et al.
(författare)
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Quantifying Earth system interactions for sustainable food production via expert elicitation
- 2022
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Ingår i: Nature Sustainability. - : Springer Science and Business Media LLC. - 2398-9629. ; 5:10, s. 830-842
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Tidskriftsartikel (refereegranskat)abstract
- Several safe boundaries of critical Earth system processes have already been crossed due to human perturbations; not accounting for their interactions may further narrow the safe operating space for humanity. Using expert knowledge elicitation, we explored interactions among seven variables representing Earth system processes relevant to food production, identifying many interactions little explored in Earth system literature. We found that green water and land system change affect other Earth system processes strongly, while land, freshwater and ocean components of biosphere integrity are the most impacted by other Earth system processes, most notably blue water and biogeochemical flows. We also mapped a complex network of mechanisms mediating these interactions and created a future research prioritization scheme based on interaction strengths and existing knowledge gaps. Our study improves the understanding of Earth system interactions, with sustainability implications including improved Earth system modelling and more explicit biophysical limits for future food production.
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| 2. |
- Drüke, Markus, et al.
(författare)
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The long-term impact of transgressing planetary boundaries on biophysical atmosphere–land interactions
- 2024
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Ingår i: Earth System Dynamics. - 2190-4979 .- 2190-4987. ; 15:2, s. 467-483
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Tidskriftsartikel (refereegranskat)abstract
- Human activities have had a significant impact on Earth's systems and processes, leading to a transition of Earth's state from the relatively stable Holocene epoch to the Anthropocene. The planetary boundary framework characterizes major risks of destabilization, particularly in the core dimensions of climate and biosphere change. Land system change, including deforestation and urbanization, alters ecosystems and impacts the water and energy cycle between the land surface and atmosphere, while climate change can disrupt the balance of ecosystems and impact vegetation composition and soil carbon pools. These drivers also interact with each other, further exacerbating their impacts. Earth system models have been used recently to illustrate the risks and interacting effects of transgressing selected planetary boundaries, but a detailed analysis is still missing. Here, we study the impacts of long-term transgressions of the climate and land system change boundaries on the Earth system using an Earth system model with an incorporated detailed dynamic vegetation model. In our centennial-scale simulation analysis, we find that transgressing the land system change boundary results in increases in global temperatures and aridity. Furthermore, this transgression is associated with a substantial loss of vegetation carbon, exceeding 200 Pg C, in contrast to conditions considered safe. Concurrently, the influence of climate change becomes evident as temperatures surge by 2.7–3.1 °C depending on the region. Notably, carbon dynamics are most profoundly affected within the large carbon reservoirs of the boreal permafrost areas, where carbon emissions peak at 150 Pg C. While a restoration scenario to reduce human pressure to meet the planetary boundaries of climate change and land system change proves beneficial for carbon pools and global mean temperature, a transgression of these boundaries could lead to profoundly negative effects on the Earth system and the terrestrial biosphere. Our results suggest that respecting both boundaries is essential for safeguarding Holocene-like planetary conditions that characterize a resilient Earth system and are in accordance with the goals of the Paris Climate Agreement.
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| 3. |
- Richardson, Katherine, et al.
(författare)
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Earth beyond six of nine planetary boundaries
- 2023
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Ingår i: Science Advances. - 2375-2548. ; 9:37
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Tidskriftsartikel (refereegranskat)abstract
- 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 recovered. The transgression level has increased for all boundaries earlier identified as overstepped. As primary production drives Earth system biosphere functions, human appropriation of net primary production is proposed 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 illustrates that these anthropogenic impacts on Earth system must be considered in a systemic context.
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| 4. |
- Tobian, Arne, 1992-
(författare)
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Climate change critically affects the status of the land-system change planetary boundary
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten CMIP6 models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth’s major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (>450 ppm) leads to its critical transgression with greater severity, the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today’s boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the framework.
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| 5. |
- Tobian, Arne, 1992-, et al.
(författare)
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Climate change critically affects the status of the land-system change planetary boundary
- 2024
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Ingår i: Environmental Research Letters. - 1748-9326. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- The planetary boundaries framework defines a safe operating space for humanity. To date, these boundaries have mostly been investigated separately, and it is unclear whether breaching one boundary can lead to the transgression of another. By employing a dynamic global vegetation model, we systematically simulate the strength and direction of the effects of different transgression levels of the climate change boundary (using climate output from ten phase 6 of the Coupled Model Intercomparison Project models for CO2 levels ranging from 350 ppm to 1000 ppm). We focus on climate change-induced shifts of Earth's major forest biomes, the control variable for the land-system change boundary, both by the end of this century and, to account for the long-term legacy effect, by the end of the millennium. Our simulations show that while staying within the 350 ppm climate change boundary co-stabilizes the land-system change boundary, breaching it (>450 ppm) leads to critical transgression of the latter, with greater severity the higher the ppm level rises and the more time passes. Specifically, this involves a poleward treeline shift, boreal forest dieback (nearly completely within its current area under extreme climate scenarios), competitive expansion of temperate forest into today's boreal zone, and a slight tropical forest extension. These interacting changes also affect other planetary boundaries (freshwater change and biosphere integrity) and provide feedback to the climate change boundary itself. Our quantitative process-based study highlights the need for interactions to be studied for a systemic operationalization of the planetary boundaries framework.
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| 6. |
- Tobian, Arne, 1992-
(författare)
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Entering the dynamic risk space : Assessing planetary boundary interactions through process-based quantifications
- 2024
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The planetary boundaries framework is an effort to define a safe operating space for humanity. Its rationale is that sustainable development needs to be achieved in ways that safeguard the stability of the Earth system on which human prosperity relies. However, very few studies explicitly examine the interactions of the Earth system processes that underlie individual boundaries.My overarching research question is: how can continued anthropogenic climate change affect the geospatially resolvable land and water planetary boundaries, and what are the implications for human livelihood? For most of my analysis, I use the LPJmL dynamic global vegetation model because it contains suitable process representations that provide a dynamic and adaptive Earth system perspective for my investigation of key planetary boundary interactions of the climate, land, water and ecosystem nexus.Paper I emphasizes the importance of green water dynamics (that is terrestrial precipitation, evapotranspiration and plant-available soil moisture) for ecosystem resilience and human well-being. The underlying analysis suggests that the current status of the proposed planetary boundary for green water is already transgressed. Paper II reveals long-term spatiotemporal dynamics of planetary boundary interactions as breaching the climate change boundary critically affects the world’s major forest biomes. Notably, the most extreme climate change scenarios led to the emergence of a southern boreal dieback in the simulations. Tropical forests further show a shift from evergreen to deciduous rainforest, an important process which is not captured by the definition of the land-system change boundary. Maintaining climate change at the planetary boundary co-stabilizes the land-system change boundary. Paper III extends the biophysical understanding of planetary boundary interactions by discussing their impact on human livelihood and the attainment of the Sustainable Development Goals. Future climate change causes increases in dry anomalies of green water in ~30% of the global land area by the end of the century. As of today (here referring to 2015), nearly a quarter of the world population and ~28% of global harvest would be affected. The dynamic risk space terminology is established to fill the conceptual gap in the analysis of planetary boundary interactions. Paper IV highlights how planetary stability constitutes the non-negotiable fundament for human development and argues why the Sustainable Development Goals have to be aligned with the planetary boundaries framework and which perils might arise from their interactions. Paper V presents the land-system change reallocation tool algorithm which allows for a scenario-driven rearrangement of human land-use to meet varying transgression levels of the land-system change boundary. My results of Paper I-V advance the understanding of interactions in the planetary boundaries framework. Moreover, my analysis in a process-based and validated modeling environment gives spatiotemporal detail of the processes at play that exceeds the potential of previously used conceptual models. My work fills a crucial gap in the operationalization of the planetary boundary framework by providing insights into how and where different policy options produce positive or negative outcomes across boundaries. The holistic understanding I present is a prerequisite for any application of the planetary boundaries framework that focuses on future conditions.
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| 7. |
- Tobian, Arne, 1992-
(författare)
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Planetary Boundaries interactions and food production: Exploring the dynamic risk space
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- The world is faced with the task of addressing rising food insecurities amidst growingpopulation and planetary boundary transgressions. Here we analyze interactions of theplanetary boundaries for climate change and freshwater change (focused on green water,i.e. soil moisture departures from pre-industrial variability ranges) and discuss potentialeffects on food production and security. By forcing the dynamic global vegetation modelLPJmL5.1 with an ensemble of 10 CMIP6 climate models under the RCP7.0 emissionsscenario, we detect significant increases in dry deviations for green water in nearly a third ofthe terrestrial surface area by the end of the century (2071-2100), compared to current levels. This implies a narrowing of the safe operating space, as thetransgression of the climate change boundary adversely affects the status of the green2water boundary. This finding is crucial, as rainfed agriculture, a food production systemexclusively relying on green water, is currently responsible for more than 60% of global foodproduction. We further argue that green water has to be made explicit in the SDG goals andtargets.
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| 8. |
- Tobian, Arne, 1992-
(författare)
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The Land-Use Change Allocation Tool (lucatoo) and its application to the planetary boundary of land-system change
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Anthropogenic modifications and alterations of terrestrial ecosystems by land-usetransformation and intensification are a driving factor of global environmental change in theAnthropocene. The planetary boundary for land-system change (PB-LSC) demarcates ‘safe’planetary conditions for these interferences and is defined by the remaining extent for themajor forest biomes spanning the temperate, tropical and boreal climatic zones. However,agricultural production and its interlinked land-use changes have contributed to thetransgression of several other planetary boundaries, besides PB-LSC. This makes scenariosrepresenting different pressure levels of PB-LSC an essential prerequisite to study how afurther breaching of the boundary would affect other interconnected planetary boundariessuch as those for climate change, biosphere integrity, freshwater change andbiogeochemical cycling. Future policy-relevant projections of land-use change are based onsocioeconomic pathways, yet no scenarios are aligned with the definition provided byPB-LSC. Here, we present a land use reallocation tool that can represent, globally at gridcell scale, the spatial distribution of agricultural land-use to match any statuses andtransgression levels of PB-LSC, e.g. to facilitate systematic assessment of effects ofdifferent afforestation and deforestation scenarios on the status of other boundaries.
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| 9. |
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| 10. |
- Wang-Erlandsson, Lan, et al.
(författare)
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A planetary boundary for green water
- 2022
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Ingår i: Nature Reviews Earth & Environment. - : Springer Science and Business Media LLC. - 2662-138X. ; 3:6, s. 380-392
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Tidskriftsartikel (refereegranskat)abstract
- Green water — terrestrial precipitation, evaporation and soil moisture — is fundamental to Earth system dynamics and is now extensively perturbed by human pressures at continental to planetary scales. However, green water lacks explicit consideration in the existing planetary boundaries framework that demarcates a global safe operating space for humanity. In this Perspective, we propose a green water planetary boundary and estimate its current status. The green water planetary boundary can be represented by the percentage of ice-free land area on which root-zone soil moisture deviates from Holocene variability for any month of the year. Provisional estimates of departures from Holocene-like conditions, alongside evidence of widespread deterioration in Earth system functioning, indicate that the green water planetary boundary is already transgressed. Moving forward, research needs to address and account for the role of root-zone soil moisture for Earth system resilience in view of ecohydrological, hydroclimatic and sociohydrological interactions.
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