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ITS3.2/NH10.7

Climate change is projected to result in an increase in extreme and compound weather events, which pose a growing threat to human well-being and the achievement of the UN Sustainable Development Goals (SDGs). Further warming is also projected to reduce the efficacy of carbon sinks acting as negative feedbacks on warming and increase the risk of crossing tipping points and triggering cascading changes in the climate and ecosystems. These processes may reduce the Earth system’s resilience, which has the potential to further amplify climate change and extremes and worsen societal impacts.

Maintaining Earth in the Holocene-like conditions that have enabled the development of the world’s societies will require better understanding of feedbacks and tipping dynamics in both the human world and the biophysical Earth. Societies will need to embark on rapid socio-economic and governance transformations in order to both reduce the risk of triggering tipping points and to improve societal resilience to increasingly likely extreme events. Earth resilience brings the complex dynamics and perturbations associated with human activities into Earth system analysis, and increasingly captures socio-economic as well as biophysical dynamics.

In this session we welcome transdisciplinary and cross-scale contributions relating to climate extremes, tipping dynamics, and Earth resilience, covering topics ranging from the cascading impacts of extreme and compound events, key feedbacks and tipping points in both biophysical and human systems, enhancing societal resilience to extreme events, and the potential for rapid social transformations to global sustainability.

Public information:
EGU 2020 Session TS3.2/NH10.7
Climate Extremes, Tipping Dynamics, and Earth Resilience in the Anthropocene
6 May, 14:00-18:00

This session will run as an EGU website hosted text-based chat accessible here, as well as through a simultaneous Zoom video room (link to be provided during the livechat).

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When joining the Zoom session remember to mute yourself, and to ask questions please raise your hand (available from the 'participants' button) and unmute when the chair calls on you. If you are a presenter, unmute when called on and share your screen if you have a few slides to show. Each presenter gets 10 minutes max including Q&A, so we suggest presenting some summary slides for a few minutes and then taking questions for the rest.

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Co-organized by BG1/CL2/CR7/NP8/OS1, co-sponsored by Future Earth
Convener: Felix Riede | Co-conveners: David Armstrong McKayECSECS, Jana Sillmann, Jonathan Donges, Dorothea Frank, Sarah Cornell, Ricarda Winkelmann
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| Wed, 06 May, 14:00–18:00 (CEST)

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Session materials Download all presentations (217MB)

Chat time: Wednesday, 6 May 2020, 14:00–15:45

D2284 |
EGU2020-20192
| Highlight
Ana Maria Vicedo Cabrera, Francesco Sera, Rochelle Schneider dos Santos, Aurelio Tobias, Christopher Astrom, Yuming Guo, Yasushi Honda, Anna Delucca, David Hondula, Dolores Ibarreta, Veronika Huber, and Antonio Gasparrini

On behalf of the Multi-Country Multi-City Collaborative (MCC) Research Network.

Background & Aim: Climate change is considered the most important environmental threat to human health. Substantial mortality and morbidity burden have been directly or indirectly attributed to climate-sensitive environmental stressors. However, limited quantitative evidence exists on how much of this burden can be attributed to man-made influences on climate. In this large health attribution study, we aimed at quantifying the proportion of excess heat-related mortality attributed to anthropogenic climate change in recent decades across 626 locations across 41 countries in various regions of the world included in MCC database.

Methods: We first estimated the location-specific heat-mortality associations through two-stage time-series analyses with quasi-Poisson regression with distributed lag non-linear models and multivariate multilevel meta-regression using observed data. We then quantified the heat-related excess mortality in each location using daily modelled series derived from historical (factual) and preindustrial control (counterfactual) simulations from 5 general circulation models (ISIMIP2b database) in the period between 1991 and 2019. We finally computed the proportion of heat-related excess mortality attributable to anthropogenic influences as the difference between the two scenarios, with associated measures of uncertainty.

Results: We found a steep increase in level of warming, expressed as the difference in annual average temperature between scenarios, with an average increase of 1.0°C (from 0.7°C  to 1.2°C) across the 626 locations between 1991 and 2019. Overall excess heat-mortality fractions of 1.92% [95% confidence interval: 0.41, 3.25] and 1.28% [0.20, 2.50] were estimated under the factual and counterfactual scenarios, respectively, with an overall difference of 0.76% [0.25,1.74]. This translates to 33% of historical heat-excess mortality that can be attributed to anthropogenic climate change. Larger proportions were found in North America (46%), Central America (47%), South America (43%), South Africa (48%), Middle-East Asia (61%), South East-Asia (50%) and Australia (42%), although highly imprecise in most of cases.

Conclusions: Our findings suggest that current warming driven by anthropogenic influences is already responsible for a considerable proportion of the heat-related mortality burden. These results stress the importance of strengthening current mitigation strategies to reduce further warming of the planet and related health impacts.

How to cite: Vicedo Cabrera, A. M., Sera, F., Schneider dos Santos, R., Tobias, A., Astrom, C., Guo, Y., Honda, Y., Delucca, A., Hondula, D., Ibarreta, D., Huber, V., and Gasparrini, A.: A global attribution study on historical heat-related mortality impacts attributed to climate change., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20192, https://doi.org/10.5194/egusphere-egu2020-20192, 2020

D2285 |
EGU2020-14050
Michael Bahn

The ability of ecosystems to resist and recover from climate extremes is of fundamental societal importance given the critical role of ecosystems in supplying ecosystem services such as food and fiber production, or water and climate regulation. To date there is a lack of understanding of how the projected increases in the frequency and intensity of climate extremes will affect ecosystems in a future world. Will the legacy of past extreme climatic events alter ecosystem responses to subsequent extreme events? What are the thresholds of severity altering ecosystem recovery from extreme events or causing irreversible shifts in ecosystem functioning? How do ecosystems respond to climate extremes in the context of multiple co-occurring environmental changes, including climate warming, elevated atmospheric CO2 concentrations, and interacting other climate extremes (i.e. ‚compound events‘)? In what ways do biodiversity and the composition of species and their traits affect ecosystem resilience? How do land management and land-use changes alter ecosystem responses to climate extremes? In this talk I will show some recent insights on these questions and will illustrate how observations can be placed in a framework permitting a comparable quantification of resilience across different ecosystems, ecosystem functions and services. Finally, I will discuss implications for enhancing the adapaptive capacity of social-ecological systems to absorb climate extremes.

How to cite: Bahn, M.: Climate extremes and ecosystem resilience in a future world, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-14050, https://doi.org/10.5194/egusphere-egu2020-14050, 2020

D2286 |
EGU2020-6681
Diyang Zhang, Xiuqi Fang, and Yanjun Wen

The effectiveness of adaptation to climate change depend on the social resilience. Historical case studies of climate change adaptations would be conducive to better understanding the preferred solution of people with different cultural background, and coping with the risk of the ongoing global climate changes. The relationship among climate change, adaptations and social resilience are analyzed based on the previous researches about famines, agricultural production, trade and migration in Germany during the 16th to the early 20th century. Differences in the primary choices and their effectiveness between Germany and China are also discussed from the perspective of food security. The results are as follows. (1) In the 16th and 17th centuries, the German agricultural system was quite sensitive to the cold and abrupt fluctuated climate, and poor harvests always accompanied by famines in which more than 30% were severe famines. After 1700AD, the severity of famine and its correlation with temperature declined gradually. About 29% famines were merely considered as dearth, and the only severe famine (1770-1772AD) occurred after a back-to-back harvest failure. However, the impact of rainfall extremes on harvest still existed. (2) Germany successfully escaped from famine after 1850AD due to four effective adaptations: ① Planting structure adjustment, like increasing the proportion of rye, was first thought of, but the effectiveness was limited until potatoes became widely accepted. ② The rapid increase in crop yield brought by ago-technology progress reversed the trend of social resilience decreasing with population growth, but was not enough to fully offset the impact of climatic deterioration. ③ The degree of dependence on grain import reached 20% in a short time, which improved the food availability and reduced the famine risk in German mainland. ④ Three emigration waves, following the drought (1844-1846AD) and cooling (1870-1890AD) might have partly alleviated food shortage, especially at a local scale. By 1900AD, German social resilience was nearly 20 times than the scenario of lacking adaptation. (3) In contrast to Germany entered a resilience increasing period since the early 18th century, China maintained the decline of resilience as population pressure increased. Differences might be attributed to their location and culture background. China had long been a unified and powerful empire in east Asia with large internal market and self-sufficient agricultural society, which made it more prone to reduce risk through domestic adjustments, such as internal migration and government relief. When the capacity for disaster relief efforts by the government failed to meet the needs of crisis management, social resilience would drop dramatically. Whereas Germany, located in the continent with a long history of division and amalgamation, had a commercial tradition and was close to the origin of the first industrial revolution, was more willing and likely to find new approaches for food supply ensurance or risk transfer in regional exchanges.

How to cite: Zhang, D., Fang, X., and Wen, Y.: Great divergence in climate change adaptation during 1500-1900AD: A comparative study on social resilience of Germany and China from a food security perspective, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6681, https://doi.org/10.5194/egusphere-egu2020-6681, 2020

D2287 |
EGU2020-3126
| Highlight
Theodore Shepherd

The role of climate change in environmental or ecological catastrophes is generally a complex question to address, because of the importance of non-climatic factors. From a climate perspective, the latter are confounding factors, whereas from an ecological perspective, they are often the heart of the matter. How these factors are treated affects the nature of the scientific questions that can be answered. In particular, the coarse-graining required to address probabilistic questions inevitably blurs the details of any particular event, whereas these details can be retained when addressing singular questions. In this paper, based on an analysis done jointly with Lisa Lloyd, I will present several published case studies of environmental catastrophes associated with extreme weather or climate events. Whilst both the singular ‘storyline’ and probabilistic ‘risk-based’ approaches to extreme-event attribution have uses in the descriptions of such events, we find the storyline approach to be more readily aligned with the forensic approach to evidence that is prevalent in the ecological literature. Implications for the study of environmental catastrophes are discussed.

How to cite: Shepherd, T.: Climate attribution of environmental catastrophes, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3126, https://doi.org/10.5194/egusphere-egu2020-3126, 2020

D2288 |
EGU2020-21467
Amy Fallon and Marko Keskinen

Growing water scarcity around the world is a crucial issue driven by global environmental change, as well as increasing competition for water resources for different economic and social pursuits. Climate change will have far-reaching consequences for water resources, particularly through increasing frequency and intensity of extreme weather events, such as droughts and floods. Such changes will acutely impact water and food security in developing countries, where large proportions of society depend on natural resources for their livelihoods. This can significantly undermine the resilience of such complex social-ecological systems, and the fulfilment of SDGs, including water-related SDG 6.

The capacity of freshwater systems to cope with stresses and shocks can be weakened when irreversible changes occur and thresholds are exceeded. It is therefore important for water governance arrangements to incorporate characteristics such as non-linear dynamics and unpredictability. Resilience is also gaining traction as a holistic framework to examine social-ecological system components, processes and feedback loops under change across scales. However, resilience has been critiqued for its inability to appropriately reflect socio-political dynamics, including power asymmetries, cultural values, and human well-being.

In this presentation, a novel theoretical framework for studying and describing resilience is presented for the analysis of freshwater system governance, using three dimensions of resilience across multiple scales of society: absorptive, adaptive, and transformative capacity. The audience is encouraged to engage critically with the concept, asking the question “resilience of what, to what, and for whom?”. In doing so, we will also address the typically narrow technical focus on resilience, and its potential challenges in achieving societal resilience to climate extremes.

The framework is applied to Cambodia’s Tonle Sap and its hydrologically and culturally unique flood pulse system. The lake provides food security for millions, yet is undergoing negative ecological and social transformation due to pressures along the Mekong River including climate change, hydropower development, and weak governance. The changing dynamics in its flood pulse system and an increasingly complex socio-political landscape are presented through the framework, addressing both positive and negative components of resilience. In this way, the framework helps to put the current research and actions on the lake’s management into the broader context of resilience and change.

We will demonstrate absorptive and adaptive responses of people living on and around the lake, including urban migration and illegal fishing practices. The risk of so-called rigidity traps (inflexible system components) is also explored, including an increasingly resilient autocratic government regime – and the potential of such rigidity traps to undermine the resilience of the overall system. An enduring status quo of narratives around agriculture and hydropower development is shown as a key aspect of resilience of the Tonle Sap. Finally, we will present the key windows of opportunity for transformation, focusing on the role of local, largely informal institutions in facilitating sustainable and equitable governance outcomes.

The key aims of this presentation are to present a novel framing of resilience that incorporates societal dimensions more fully, and to identify pathways for transformative change that benefit all relevant groups of society.

 

How to cite: Fallon, A. and Keskinen, M.: Resilience for whom? Governing social-ecological transformation in Cambodia’s Tonle Sap Lake, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21467, https://doi.org/10.5194/egusphere-egu2020-21467, 2020

D2289 |
EGU2020-18648
Wim Thiery, Stefan Lange, Joeri Rogelj, Sonia I. Seneviratne, Carl-Friedrich Schleussner, Katja Frieler, and Nico Bauer and the ISIMIP modelling team

Will a new-born experience more impacts from climate change compared to a 60-year old? While the obvious answer to this question is yes, impacts accumulated across an average person’s lifetime have so far not been quantified. Providing such information is however relevant and timely, given the recent surge in societal debate regarding inter-generational solidarity and considering ongoing climate litigation. Here we combine multi-model impact projections from the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) with temperature trajectories from the IPCC special report on warming of 1.5°C and life expectancy data from the World Bank to compute accumulated impact exposure across lifetimes of people in different age groups and countries. We consider six impacts categories (droughts, heatwaves, tropical cyclones, crop failure, floods, and wildfires), for which ISIMIP provides a total of 170 impact projections with 15 different impact models under RCP2.6 and 6.0. Our results highlight that the combined increase in life expectancy and unfolding climate impacts leads to 2-4 times more impacts affecting a new-born compared to a 60-year old person under current policy pledges. Globally, the increase in exposure for young people is dominated by the strong increase in heatwave hazards. The strongest increases occur in low and lower-middle income countries, where rising impacts compound a substantial increase in life expectancy. Our results overall highlight the strong benefit of aligning policies with the Paris Agreement for safeguarding the future of current young generations.

How to cite: Thiery, W., Lange, S., Rogelj, J., Seneviratne, S. I., Schleussner, C.-F., Frieler, K., and Bauer, N. and the ISIMIP modelling team: The kids aren’t alright, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18648, https://doi.org/10.5194/egusphere-egu2020-18648, 2020

D2290 |
EGU2020-10527
Tabea Lissner

The level of detail to understand the impacts associated with different levels of global temperature increase across space and time is increasing with and since the publication of the IPCC Special Report on Global Warming of 1.5°C (SR1.5). However, current adaptation assessments are limited in picking up this information to understand what the implications of different impact pathways are for adaptation. Yet, the intensity, frequency and timing of impacts are critical determinants of the feasibility of different adaptation options and their associated costs.

There is increasing awareness that limits to adaptation are likely to be approached or crossed with higher levels of warming, however differential analyses of adaptation needs as a consequence of different warming pathways are so far limited. While case study based assessment of warming- and scenario-depend adaptation responses are emerging, so far an aggregated regional to global assessment is lacking.

Adaptation is often seen as a process that can draw on existing approaches that have been successfully implemented elsewhere, assuming that a linear increase of impacts would allow impacted regions to scale existing approaches to deal with hazards. However, climate impacts are unlikely to increase in a linear fashion across space and time and we are likely to enter new regimes of impacts in terms of intensity and frequency, with implications on recovery times. As a consequence, existing approaches are unlikely to be able to respond to these fundamentally changed conditions and limits to adaptation as we know it are likely to be reached. Understanding adaptation needs and potentials at different levels of global warming is therefore an urgent need in order to understand the full scale of the challenge. Such information is also critical in understanding the full cost of different mitigation pathway choices.

This contribution presents a framework for the systematic assessment of warming-level dependent adaptation needs and potentials across sectors and presents first results of this approach in the context of adaptation in the water sector. Our results highlight the need for differentiated approaches to planning adaptation, drawing a strong link to available impacts and vulnerability science to avoid mal-adaptation and to understand the full scope of the challenge. Where transformational adaptation will be required and current warming trajectories, early action may reduce associated costs of such measures across different dimensions, including financial, social or cultural aspects.

How to cite: Lissner, T.: Warming-level dependent adaptation requirements and consequent limits to adaptation, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-10527, https://doi.org/10.5194/egusphere-egu2020-10527, 2020

D2291 |
EGU2020-11591
| solicited
Markus Reichstein and the RISK-KAN

In this talk we highlight the consideration of extreme events for (Earth) system dynamics and sustainable development, as opposed to perspective which mostly perceive gradual changes. We show that climate extremes can contribute to positive carbon-cycle-climate feedbacks and conjeture that extreme events can trigger fast system changes and the instigation of "vicious cycles", illustrating this conceptually with ecosystem-related and societal examples. We further discuss risk cascades, emergent and systemic risks in this context with recent local and more global example. Counter-strategies will also be elaborated. Overall, we propose to consider more strongly risk-aware development and systems thinking in future research and implementation related to extreme events and resilience. 

How to cite: Reichstein, M. and the RISK-KAN: Extreme events and resilience at different scales, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11591, https://doi.org/10.5194/egusphere-egu2020-11591, 2020

D2292 |
EGU2020-8486
Stephanie Horion, Paulo Bernardino, Wanda De Keersmaecker, Rasmus Fensholt, Stef Lhermitte, Guy Schurgers, Niels Souverijns, Ruben Van De Kerchove, Hans Verbeeck, Jan Verbesselt, Wim Verbruggen, and Ben Somers

Pressures on dryland ecosystems are ever growing. Large-scale vegetation die-offs, biodiversity loss and loss in ecosystem services are reported as a result of unsustainable land use, climate change and extreme events. Yet major uncertainties remain regarding our capability to accurately assess on-going land changes, as well as to comprehensively attribute drivers to these changes. Indeed ecosystem response to external pressures is often complex (e.g. non-linear) and non-unique (i.e. same response, different drivers). Besides critical knowledge on ecosystem stability and coping capacities to extreme events has still to be consolidated.

Recent advances in time series analysis and in the assessment of breakpoint open a new door in ecosystem research as they allow for the detection of turning points and tipping points in ecosystem development (Horion et al., 2016 and 2019). Identifying ecosystems that have significantly changed their way of functioning, i.e. that have tipped to a new functioning state, is of crucial importance for Ecology studies. These extremes cases of vegetation instability are golden mines for researches that try to understand how resilient are ecosystems to climate change and to non-sustainable use of land.

This is precisely what the U-TURN project is about:

  • Developing methods for detecting turning points in dryland ecosystem functioning; Here we defined turning point in ecosystem functioning as a key moment in the ecosystem development where its functioning is significantly changed or altered without implying the irreversibility of the process (Horion et al. (2016)), by opposition to the term ‘tipping point’ that implies irreversibility (Lenton et al. 2008).
  • Studying the contribution of climate and human pressure (e.g. land-use intensification, human induced land soil degradation) in pushing the ecosystem outside its safe operating space ; Here we used Earth Observation techniques coupled with Dynamic Vegetation Models to get process-based insights on the drivers of the observed changes in ecosystem functioning.
  • Exploring whether early warning signal of turning points can be identified.

During our talk, we will present key methodological advances being achieved within the U-TURN project, and showcase some of our major findings in relation to abrupt changes in dryland ecosystem functioning.

References:

Horion, S., Ivits, E., De Keersmaecker, W., Tagesson, T., Vogt, J., & Fensholt, R. (2019). Mapping European ecosystem change types in response to land‐use change, extreme climate events, and land degradation. Land Degradation & Development, 30(8), 951-963. doi:10.1002/ldr.3282

Horion, S., Prishchepov, A. V., Verbesselt, J., de Beurs, K., Tagesson, T., & Fensholt, R. (2016). Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier. Global Change Biology, 22(8), 2801-2817. doi:10.1111/gcb.13267

Lenton, T. M., Held, H., Kriegler, E., Hall, J. W., Lucht, W., Rahmstorf, S., & Schellnhuber, H. J. (2008). Tipping elements in the Earth's climate system. Proc Natl Acad Sci U S A, 105(6), 1786-1793. doi:10.1073/pnas.0705414105

 

Project website: http://uturndryland.wixsite.com/uturn

This research is funded by the Belgian Federal Science Policy Office (Grant/Award Number:SR/00/339)

How to cite: Horion, S., Bernardino, P., De Keersmaecker, W., Fensholt, R., Lhermitte, S., Schurgers, G., Souverijns, N., Van De Kerchove, R., Verbeeck, H., Verbesselt, J., Verbruggen, W., and Somers, B.: Understanding Turning Points in Dryland Ecosystem Functioning (U-TURN), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8486, https://doi.org/10.5194/egusphere-egu2020-8486, 2020

D2293 |
EGU2020-2735
| Highlight
Andrew H. MacDougall, Thomas L. Frölicher, Chirs D. Jones, Joeri Rogelj, H. Damon Matthews, and Kirsten Zickfeld and the Zero Emissions Commitment Model Intercomparison Project

The Zero Emissions Commitment (ZEC) is the change in global mean temperature expected to occur following the cessation of net CO2 emissions, and as such is a critical parameter for calculating the remaining carbon budget. The Zero Emissions Commitment Model Intercomparison Project (ZECMIP) was established to gain a better understanding of the potential magnitude and sign of ZEC, in addition to the processes that underlie this metric. Eighteen Earth system models of both full and intermediate complexity participated in ZECMIP. All models conducted an experiment where atmospheric CO2 concentration increases exponentially until 1000 PgC has been emitted. Thereafter emissions are set to zero and models are configured to allow free evolution of atmospheric CO2 concentration. The inter-model range of ZEC 50 years after emissions cease for the 1000 PgC experiment is -0.36 to 0.29 oC with a model ensemble mean of -0.06 oC, median of -0.05 oC and standard deviation of 0.19 oC. Models exhibit a wide variety of behaviours after emissions cease, with some models continuing to warm for decades to millennia and others cooling substantially. Analysis shows that both ocean carbon uptake and carbon uptake by the terrestrial biosphere are important for counteracting the warming effect from reduction in ocean heat uptake in the decades after emissions cease.

 

Overall, the most likely value of ZEC on decadal time-scales is assessed to be close to zero, consistent with prior work. However substantial continued warming for decades or centuries following cessation of emission is a feature of a minority of the assessed models and thus cannot be ruled out.

How to cite: MacDougall, A. H., Frölicher, T. L., Jones, C. D., Rogelj, J., Matthews, H. D., and Zickfeld, K. and the Zero Emissions Commitment Model Intercomparison Project: Is there warming in the pipeline? A multi-model analysis of the zero emission commitment from CO2, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2735, https://doi.org/10.5194/egusphere-egu2020-2735, 2020

D2294 |
EGU2020-20525
Lan Wang-Erlandsson, Tom Gleeson, Fernando Jaramillo, Samuel C. Zipper, Dieter Gerten, Arne Tobian, Miina Porkka, Agnes Pranindita, Ruud van der Ent, Patrick Keys, Ingo Fetzer, Matti Kummu, Anna Chrysafi, Will Steffen, Hubert Savenije, Makoto Taniguchi, Line Gordon, Sarah Cornell, Arie Staal, and Yoshihide Wada and the et. al.

The planetary boundaries framework defines nine Earth system processes that together demarcate a safe operating space for humanity at the planetary scale. Freshwater - the bloodstream of the biosphere - is an obvious member of the planetary boundary framework.  Water fluxes and stores play a key role for the stability of the Earth’s climate and the world’s aquatic and terrestrial ecosystems. Recent work has proposed to represent the water planetary boundary through six sub-boundaries based on the five primary water stores, i.e., atmospheric water, soil moisture, surface water, groundwater, and frozen water. In order to make it usable on all spatial scales we examine bottom-up and top-down approaches for quantification of the water planetary boundary. For the bottom-up approaches, we explore possible spatially distributed variables defining each of the proposed sub-boundaries, as well as possible weighting factors and keystone regions that can be used for aggregation of the distributed water sub-boundaries to the global scale. For the top-down approaches, we re-examine the stability of key biomes and tipping elements in the Earth System that may be crucially influenced by water cycle modifications. To identify the most appropriate variables for representing the water planetary boundary, we evaluate the range of explored variables with regard to scientific evidence and scientific representation using a hierarchy-based evaluation framework. Finally, we compare the highest ranked top-down and bottom-up approaches in terms of the scientific outcome and implications for governance. In sum, this comprehensive and systematic identification and evaluation of variables, weighting factors, and baseline conditions provides a detailed basis for the future operational quantification of the water planetary boundary. 

How to cite: Wang-Erlandsson, L., Gleeson, T., Jaramillo, F., Zipper, S. C., Gerten, D., Tobian, A., Porkka, M., Pranindita, A., van der Ent, R., Keys, P., Fetzer, I., Kummu, M., Chrysafi, A., Steffen, W., Savenije, H., Taniguchi, M., Gordon, L., Cornell, S., Staal, A., and Wada, Y. and the et. al.: Towards a quantification of the water planetary boundary , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20525, https://doi.org/10.5194/egusphere-egu2020-20525, 2020

D2295 |
EGU2020-7217
Arie Staal, Ingo Fetzer, Lan Wang-Erlandsson, Joyce Bosmans, Stefan Dekker, Egbert van Nes, Johan Rockström, and Obbe Tuinenburg

Tropical forests modify the conditions they depend on through feedbacks on different spatial scales. These feedbacks shape the hysteresis (history-dependence) of tropical forests, thus controlling their resilience to deforestation and response to climate change. Here we present the emergent hysteresis from local-scale tipping points and regional-scale forest-rainfall feedbacks across the tropics under the recent climate and a severe climate-change scenario. By integrating remote sensing, a global hydrological model, and detailed atmospheric moisture tracking simulations, we find that forest-rainfall feedback expands the range of possible forest distributions especially in the Amazon. The Amazon forest could partially recover from complete deforestation, but may lose that resilience later this century. The Congo forest lacks resilience, but gains it under climate change, whereas forests in Australasia are resilient under both current and future climates. Our results show how tropical forests shape their own distributions and create the climatic conditions that enable them.

How to cite: Staal, A., Fetzer, I., Wang-Erlandsson, L., Bosmans, J., Dekker, S., van Nes, E., Rockström, J., and Tuinenburg, O.: Hysteresis of tropical forests in the 21st century, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-7217, https://doi.org/10.5194/egusphere-egu2020-7217, 2020

D2296 |
EGU2020-21230
| Highlight
Ilona M. Otto and Jonathan Donges

Safely achieving the goals of the Paris Climate Agreement requires a world-wide transformation to carbon-neutral societies within the next 30 years. Accelerated technological progress and policy implementations are required to deliver emissions reductions at rates sufficiently fast to avoid crossing dangerous tipping points in the Earth’s climate system. Here, we discuss and evaluate the potential of social tipping interventions (STIs) that can activate contagious processes of rapidly spreading technologies, behaviors, social norms and structural reorganization within their functional domains that we refer to as social tipping elements (STEs). STEs are subdomains of the planetary socio-economic system where the required disruptive change may take place and lead to a sufficiently fast reduction in anthropogenic greenhouse gas emissions. The results are based on online expert elicitation, a subsequent expert workshop, and a literature review. The social tipping interventions that could trigger the tipping of STE subsystems include (i) removing fossil fuel subsidies and incentivizing decentralized energy generation (STE1: energy production and storage systems), (ii) building carbon-neutral cities (STE2: human settlements), (iii) divesting from assets linked to fossil fuels (STE3: financial markets), (iv) revealing the moral implications of fossil fuels (STE4: norms and value systems), (v) strengthening climate education and engagement (STE5: education system) and (vi) disclosing information on greenhouse gas emissions (STE6: information feedbacks). Our research reveals important areas of focus for larger-scale empirical and modeling efforts to better understand the potentials of harnessing social tipping dynamics for climate change mitigation.

How to cite: Otto, I. M. and Donges, J.: Social tipping dynamics for stabilizing Earth’s climate by 2050, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21230, https://doi.org/10.5194/egusphere-egu2020-21230, 2020

D2297 |
EGU2020-21493
Kees van Ginkel, Wouter Botzen, Marjolijn Haasnoot, Gabriel Bachner, Karl Steininger, Jochen Hinkel, Paul Watkiss, Esther Boere, Ad Jeuken, Elisa Sainz de Murieta, and Francesco Bosello

The concept of tipping points has received much attention in research on climate change. In the biophysical realm, climate tipping points describe critical thresholds at which large-scale elements of the Earth switch to a qualitatively different state; and ecological tipping points describe thresholds separating distinct dynamic regimes of ecosystems. The tipping point metaphor is also used to indicate transformative change in adaptation and mitigation strategies. However, there remains an underexplored field: climate change induced socio-economic tipping points (SETPs). We define an SETP as: a climate change induced, abrupt change of a socio-economic system, into a new, fundamentally different state. We make a distinction between SETPs in terms of transformational response to climate change and SETPs in terms of socio-economic impacts.

SETPs are points where a gradual change in climatic conditions causes an abrupt, fundamental reconfiguration of the socio-economic system. Through a stakeholder consultation, we identified 22 candidate SETP examples with policy relevance for Europe. Three of these were investigated in more detail, with special attention for their tipping point characteristics (stable states at both sides of a critical threshold, abrupt transition between those states, and the mechanism explaining the non-linear and abrupt behaviour).

The first example is the collapse of winter sports tourism in low-altitude ski resorts. In the face of climate change, this may occur abrupt, cause a fundamental reconfiguration of the local and regional economy, and is very hard to reverse. In some cases, it could be possible to achieve a fundamental shift towards summer tourism.

The second example is the farmland abandonment in Southern Europe. Large parts of Spain have already seen widespread farmland abandonment and associated migration. Increasing heat and drought may worsen the conditions, with considerable social, and to a lesser extent, economic consequences. On the local scale, this manifests itself as a clear SETP: a lively agricultural area suddenly tips to the ‘Spanish Lapland’: deserted farms, villages with ageing population, little economic activity and underdeveloped infrastructure and facilities.

The third example is sea-level rise induced reconfiguration of coastal zones. In the face of accelerating sea level rise (SLR), threatened communities may retreat from vulnerable coastal zones. This may be caused by migration (voluntary human mobility), displacement (involuntary movement following a disaster) or relocation (retreat managed by the government). The SETP of retreat from a certain area is usually triggered by a flood event. However, also the adaptation to increasing flood risk may be so transformative, that it can be considered a structural configuration of the system. This is currently seen in The Netherlands, where studies on extreme SLR have triggered a debate in which very transformative strategies are proposed, such as: constructing a dike in front of the entire coast, retreat from areas with economic stagnation and population decline, or elevating all new buildings above sea level.

A key insight is that the rate of climate change may exceed the capacity of society to adapt in the traditional way, triggering a shift towards fundamentally different policies and a reconfiguration of the socio-economic system.

How to cite: van Ginkel, K., Botzen, W., Haasnoot, M., Bachner, G., Steininger, K., Hinkel, J., Watkiss, P., Boere, E., Jeuken, A., Sainz de Murieta, E., and Bosello, F.: Climate change induced socio-economic tipping points , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21493, https://doi.org/10.5194/egusphere-egu2020-21493, 2020

D2298 |
EGU2020-2374
Jingfang Fan, Jun Meng, Josef Ludescher, Zhaoyuan Li, Elena Surovyatkina, Xiaosong Chen, Juergen Kurths, and Hans Joachim Schellnhuber

The Indian summer monsoon rainfall (ISMR) has decisive influence on India's agricultural output and economy. Extreme departures from the normal seasonal amount of rainfall can cause severe droughts or floods, affecting Indian food production and security.  Despite the development of sophisticated statistical and dynamical climate models, a long-term and reliable prediction of ISMR has remained a challenging problem.  Towards achieving this goal, here we construct a series of dynamical and physical climate networks based on the global near surface air temperature field. We uncover that some characteristics of the directed and weighted climate networks can serve as good early warning signals for ISMR forecasting. The developed prediction method can produce a forecast skill of 0.5, by using the previous calendar year's data (5-month lead-time). The skill of our ISMR forecast is comparable to the best statistical and dynamical forecast models, which start in May or June. We reveal that global warming  affects climate network, by enchanting cross-equatorial teleconnections between Southwest Atlantic and North Asia-Pacific, which significantly impacts on  global precipitation. Remarkably, the consequences of climate change lead to improving the prediction skills. We discuss the underlying mechanism of our predictor and associate it with network--delayed--ENSO and ENSO--monsoon connections. Moreover, we find out that this approach is not limited to prediction of all India rainfall but also can be applied to forecast the Indian homogeneous regions rainfall. Our network-based approach developed in the present work provides a new perspective on the regional forecasting of the ISMR, and can potentially be used as a prototype for other monsoon systems.

 

How to cite: Fan, J., Meng, J., Ludescher, J., Li, Z., Surovyatkina, E., Chen, X., Kurths, J., and Schellnhuber, H. J.: Indian Monsoon Rainfall Amount Forecast: Network-based Approach and Climate Change Benefits, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2374, https://doi.org/10.5194/egusphere-egu2020-2374, 2020

D2299 |
EGU2020-4335
Banzragch Nandintsetseg, Bazartsersen Boldgiv, Jinfeng Chang, Philippe Ciais, Masato Shinoda, Yong Mei, and Nils Christian Stenseth

Robust changes in climatic hazards, including droughts, heatwaves and dust storms, are evident in many parts of the world and they are expected to increase in magnitude and frequency in the future. At the same time, socio-ecological damage from climate-related disasters has increased worldwide, including the Eurasian steppes, notably Mongolian grasslands (MGs), which occur in arid and harsh cold climate and still support traditional nomadic livelihood and culture through the food supply, and agricultural and ecosystem services. In the 2000s, increasing climate disasters (droughts combined with anomalously harsh winters (dzuds in Mongolian), and dust storms) resulted in massive livestock deaths, causing socioeconomic stagnation. In this context, assessments of risk and vulnerability of MGs to climate change and grazing may support disaster risk management by helping to identify hazard risk hotspots, allowing herders in risky areas to be prepared for events, and to mitigate the future potential impacts. Here, we examine the risk and vulnerability of the MG ecosystem to droughts at the national-level during a 40-year (1976–2015) using simulations of a gridded process-based ecosystem model by contrasting the recent (1996–2015) and past (1976–1995) 20-years. In general, the model realistically simulates temporal and spatial variations of vegetation biomass and soil moisture that were captured by field and satellite observations during 2000–2015 over MGs. We apply a probabilistic risk analysis in which risk is the product of the probability of hazardous drought during June-August and ecosystem vulnerability. Results reveal that during 1976–2015, increases in droughts with rapid warming and slight drying occurred over MGs, particularly in the recent 20-year, accompanied by ever-increasing grazing intensity, which together resulted in declining trends in grassland productivity. During the recent 20-year, the risk of drought to productivity slightly increased over extended areas in MGs compared to the past 20-year. The increase in the risk to MGs predominantly caused by the climate change-induced increase in the probability of hazardous drought, and less by the vulnerability. Regionally, recent droughts modify the risk to grasslands particularly in northcentral and northeast Mongolia. Given the benefits of MGs for both ecosystem services and socio-economic consequences, recent increases in drought hazards and associated risk to MGs signal an urgent need to implement drought management policies that sustain MGs.

How to cite: Nandintsetseg, B., Boldgiv, B., Chang, J., Ciais, P., Shinoda, M., Mei, Y., and Stenseth, N. C.: Risk and vulnerability of Mongolian grasslands to climate change and grazing, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4335, https://doi.org/10.5194/egusphere-egu2020-4335, 2020

D2300 |
EGU2020-4490
Ann Kristin Klose, Volker Karle, Ricarda Winkelmann, and Jonathan F. Donges

In ecology, climate and other fields, systems have been identified that can transition into a qualitatively different state when a critical threshold or tipping point in a driving process is crossed. An understanding of those tipping elements is of great interest given the increasing influence of humans on the biophysical Earth system. Tipping elements are not independent from each other as there exist complex interactions, e.g. through physical mechanisms that connect subsystems of the climate system.
Based on earlier work on such coupled nonlinear systems, we systematically assessed the qualitative long-term behavior of interacting tipping elements. We developed an understanding of the consequences of interactions on the tipping behavior allowing for domino effects and tipping cascades to emerge under certain conditions.
The application of these qualitative results to real-world examples of interacting tipping elements shows that domino effects with profound consequences can occur: the interacting Greenland ice sheet and thermohaline ocean circulation might tip before the tipping points of the isolated subsystems are crossed. The eutrophication of the first lake in a lake chain might propagate through the following lakes without a crossing of their individual critical nutrient input levels.  
The possibility of emerging domino effects calls for the development of a unified theory of interacting tipping elements and the quantitative analysis of interacting real-world tipping elements.

How to cite: Klose, A. K., Karle, V., Winkelmann, R., and Donges, J. F.: Dynamic emergence of domino effects in systems of interacting tipping elements in ecology and climate, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4490, https://doi.org/10.5194/egusphere-egu2020-4490, 2020

D2301 |
EGU2020-4630
Franziska Gaupp and Jana Sillmann

In a globalized world, Europe is increasingly affected by climate change events beyond its borders that propagate through our interconnected systems impacting the socio-economic welfare in Europe. The REmote Climate Effects and their Impact on European sustainability, Policy and Trade (RECEIPT) project uses a novel stakeholder-driven storytelling approach that maps representative connections between remote climate hazards such as droughts or hurricanes and European socio-economic activities in the agricultural, finance, development, shipping and manufacturing sectors. As part of RECEIPT, this work focuses on systemic risks in global climate risk hotspots and their knock-on effects on the European economy. In five stakeholder workshops, expert elicitation methods are used to identify and map sector- and storyline-specific systemic risks: interlinkages between different events, hidden causes and consequences, potential feedback loops, uncertainties and other systemic risk characteristics will be investigated. A special focus lies on “gray rhino” events, “foreseeable random surprises” that follow clear warning signs but are only known to a smaller group of people. Results reveal sector-specific “topographies of risk” within the storylines identified by stakeholders.

How to cite: Gaupp, F. and Sillmann, J.: Systemic risks emerging from global climate hotspots and their impacts on Europe, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4630, https://doi.org/10.5194/egusphere-egu2020-4630, 2020

D2302 |
EGU2020-9696
Chandrakant Singh, Ruud J. van der Ent, Ingo Fetzer, and Lan Wang-Erlandsson

Change in rainfall patterns and extended drought events can cause water stress in the rainforest which can also lead to a permanent shift of the biome into a savanna state. Rainforest in response may adapt to such environmental stress conditions to sustain ecosystem functioning or reduce functioning altogether. Previous studies related to forest resilience have mostly relied on precipitation or climatological drought as a control variable, but neither is a direct measure of forest resilience. As such, forest adaptability dynamics of the forest is poorly understood. Our research defines this adaptation capacity of vegetation as a dynamic reserve which rainforest can utilize before a potential shift to an alternate stable state, as the resilience of the rainforest. Here, we introduce the Rootzone Storage Potential (RZSP) as a direct water stress metric to understand adaptive forest resilience behaviour, using the cumulative difference between precipitation and potential evaporation (radiation-based). Since the potential evaporation used for RZSP calculation is purely radiation-based, it minimizes the effect of moisture recycling (and transport) on the system. RZSP is the potential of vegetation to optimize their resources enduring the greatest dry period. In this study, we have investigated the spatio-temporal resilience loss of the South American and African rainforest. An increasing trend of resilience loss was observed in the past few decades. Using RZSP is a useful indicator for estimating resilience dynamics and water stress characteristics of the rainforest. 

How to cite: Singh, C., van der Ent, R. J., Fetzer, I., and Wang-Erlandsson, L.: Rootzone storage potential indicates the extent of rainforest resilience, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9696, https://doi.org/10.5194/egusphere-egu2020-9696, 2020

D2303 |
EGU2020-12439
haiyang liu

Natural disasters will bring a huge threat to the safety of human life and property. When disasters happen, leaders at all levels need to respond in time. Emergency plans can be regarded as the effective guidance of natural disaster emergency responses, and they include the textual descriptions of emergency response processes in terms of natural language. In this paper, we propose an approach to automatically extract emergency response process models from Chinese emergency plans, and can automatically generate appropriate emergency plans. First, the emergency plan is represented as a text tree according to its layout markups and sentence-sequential relations. Then, process model elements, including four-level response condition formulas, executive roles, response tasks, and flow relations, are identified by rule-based approaches. An emergency response process tree is generated from both the text tree and extracted process model elements, and is transformed to an emergency response process that is modeled as business process modeling notation. Finally, when different disasters occur, a new plan is generated according to the training of historical plan database. A large number of experiments in the actual emergency plan show that this method can extract the emergency response process model, and can generate a suitable new plan.

How to cite: liu, H.: Intelligent Extraction and Generation Technology of Emergency Plan, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12439, https://doi.org/10.5194/egusphere-egu2020-12439, 2020

D2304 |
EGU2020-13341
Raphael Neukom, Nadine Salzmann, Christian Huggel, Veruska Mucchione, Sabine Kleppek, and Roland Hohmann

The study on ‘climate-related risks and opportunities’ of the Swiss Federal Office for the Environment (FOEN) provides a comprehensive analysis of climate-related risks and opportunities for Switzerland until 2060. The synthesis of the study results has been the basis for the development of adaptation strategies and measures in Switzerland. The study also identifies knowledge gaps and related missing planning tools for risks, which are difficult to assess as they typically have a low probability of occurrence but have potentially very high impacts for society and/or the environment. Such risks refer in particular to risks, which cumulate through process cascades or are triggered by meteorological/climatic extremes events, which return within shorter time intervals than expected.

To respond to these gaps, a collaborative effort including academic and government institutions at different administrative levels is undertaken in order to explore and analyse the potential of such cumulative risks and actions needed to manage them in Switzerland. The project focuses on two case studies, which are developed in consultation with stakeholders from science, policy and practice at the national and sub-national level.

The case studies analyse risks triggered by meteorological events based on projected and recently published Swiss Climate Scenarios CH2018, considering rare but plausible scenarios where such triggering events cumulate and/or occur in combinations.

We discuss international terminologies and experience with unexpected and cumulative extreme events and put them in relation to the Swiss context. Specifically, we present the cascading processes of the first case study, which focuses on the protective forests in the eastern Swiss Alps. Potential reduction of the protective capacity caused by extreme drought and heat and subsequent increase of risks caused by multiple natural hazards, such as fires and mass movements (snow avalanche, landslide), are assessed in this case study using semi-quantitative methods of risk analysis.

How to cite: Neukom, R., Salzmann, N., Huggel, C., Mucchione, V., Kleppek, S., and Hohmann, R.: Analysis and management of unexpected and cumulative climate risks in Switzerland, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13341, https://doi.org/10.5194/egusphere-egu2020-13341, 2020

D2305 |
EGU2020-13529
Young Hye Bae, Jaewon Jung, Imee V. Necesito, Soojun Kim, and Hung Soo Kim

Due to global warming, Arctic temperatures are rising, resulting in the fall of polar vortex, a cold Arctic air, causing heavy snow and a record-breaking cold wave in the middle latitude northern hemisphere. A record-breaking cold wave and extreme snowfall have paralyzed infrastructure and caused enormous human and property damage. In this study, we analyzed the deployment characteristics of winter climate that affect the extreme snowfall on the Korean Peninsula. The European Centre for Medium-Range Weather Forecasting (ECMWF) data provided by the Copernicus Climate Change Service (C3S) was used to analyze the characteristics of climate factors around the Korean Peninsula. The period of all data was from November to March, the winter season of South Korea. Teleconnections were analyzed using climatic factors such as snowfall, humidity, air pressure, wind and sea surface temperature to analyze the characteristics of climate factors affecting the heavy snowfall on the Korean Peninsula. The results of the future main study are expected to be used as basic data to predict the occurrence and impact of heavy snow in areas surrounding the Korean Peninsula in the future and to assess its vulnerability to damage from the snowfall.

How to cite: Bae, Y. H., Jung, J., Necesito, I. V., Kim, S., and Kim, H. S.: An Analysis of the Characteristics of Adjacent Climatic Factors Affecting Extreme Snowfall on the Korean Peninsula, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13529, https://doi.org/10.5194/egusphere-egu2020-13529, 2020

Chat time: Wednesday, 6 May 2020, 16:15–18:00

D2306 |
EGU2020-2809
Tianhai Jiang

The devastating impact of natural hazards on social and economic development worldwide and on the security of human and natural systems, is well-known, as is their impact on the most vulnerable. The intensity and frequency of disasters are exacerbated by climate changes, and increasing concomitant losses due to rapid urbanization and poor planning decisions, among other factors.

The International Association for Disaster Risk Reduction (IADRR) is an international, non-governmental, professional body of individual membership, devoted to the development of global disaster risk reduction (DRR) endeavors with emphases on:

  • Interdisciplinary, multi-sector, and multi-stakeholder cooperation among all categories of DRR professionals.
  • Exchanging knowledge and ideas, research outputs and practical experiences, establishing a trans-disciplinary science and technology application interface.
  • Promoting disciplinary development of disaster risk sciences and engineering, increasing risk awareness and education among the general public for resilient communities.

DRR is a global challenge, complicated, interplayed, and widely dispersed. It is only through multi-national, multi-sector, and interdisciplinary efforts, that DRR challenges can be dealt with at our best. At present, there are many well-established organizations focusing on specific natural hazards (e.g., earthquake, landslides) or certain aspect of disaster issues (emergency management), while no comprehensive international association for DRR professionals of different disciplines (e.g., social, natural and healthcare sciences), sectors (engineers, urban planners, emergency responders, private), which can jointly tackle the complex real-world DRR challenges, and to connect professionals with different expertise for collaborative implementation of Sendai Framework, SDGs and Paris Agreement.

It is through more effective collaborations among all related communities, through broader vision and social consensus-building, through influencing policy-making process and governance at various scales of actions, and exploring application interface, that the most effective new approaches to DRR can be sought.

Uniqueness and Synergies

  • An overarching networking umbrella for individual professionals
  • A sense of belonging and career development platform for all categories of professionals
  • A science and application interface to promote research and public education and to bring science into action
  • An expert and talent pool of different expertise for long-term communication and transboundary cooperation
  • Synergize with existing mechanisms as a united front for real-world DRR challenges

Missions

    • 1. Online & Offline networks
    • 2. Filling the gaps between research, practice and policy
    • 3. Expert and talent pool of DRR professionals for expertise and career development
    • 4. Promote disaster risk science and risk awareness
    • 5. Information sharing and application
    • 6. Career development

The Association was well discussed among dozens of international/national/regional DRR organizations, such as UNDRR, ISC, IRDR, ADPC, IPCC, UNESCAP, WFEO, etc., and will have an official debut on the opening of Asia-Pacific Science & Technology Conference on Disaster Risk Reduction (APSTCDRR) in Malaysia on March 16. EGU will be our one of the first big events after our launching. We would like to share our ideas as a broader umbrella for DRR professionals for a fully mobilized and proactive international community of practice for disaster resilient societies, and to ensure the safe, resilient and sustainable development of human society.

Co-Chairs of the Preparatory Committee for IADRR

Cui Peng Academician, Chinese Academy of Sciences (CAS); Institute of Mountain Hazards and Environment, CAS

Rajib Shaw Professor, Keio University, Japan; Chair, UNDRR Science Technology Advisory Group

How to cite: Jiang, T.: Introduction to the International Association for Disaster Risk Reduction, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2809, https://doi.org/10.5194/egusphere-egu2020-2809, 2020

D2307 |
EGU2020-3956
Juan Rocha

Ecosystems around the world are at riks of critical transitions due to increasing anthropogenic preasures and climate change. However, it is not clear where the risks are higher, or where ecosystems are more vulnerable. When a dynamic system is close to a threshold, it leaves a statistical signature on its time series known as critical slowing down. It takes longer to recover after a small disturbance, which translates into increases in variance, autocorrelation, and skewness or flickering. Here I measure critical slowing down on primary production proxies for marine and terrestrial ecosystems globally. Slowness is an indicator of potential instabilities and a proxy of resilience. While slowness is not a universal indicator for critical transitions, it can be used for detection of potential regime shifts.

How to cite: Rocha, J.: Detecting risk of regime shifts in ecosystems, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3956, https://doi.org/10.5194/egusphere-egu2020-3956, 2020

D2308 |
EGU2020-5412
Nico Wunderling, Jonathan Donges, Jürgen Kurths, and Ricarda Winkelmann

The Greenland Ice Sheet, West Antarctic Ice Sheet, Atlantic Meridional Overturning Circulation (AMOC), El-Nino Southern Oscillation (ENSO) and the Amazon rainforest have been identified as potential tipping elements in the Earth system, exhibiting threshold behavior. While their individual tipping thresholds are fairly well understood, it is of yet unclear how their interactions might impact the overall stability of the Earth’s climate system. Here, we explicitly study the effects of known physical interactions using a paradigmatic network approach which is not yet possible with more complex global circulation models or process-based models in a comprehensive way.

We analyze the risk of domino effects being triggered by each of the individual tipping elements under global warming in equilibrium experiments, propagating uncertainties in critical temperature thresholds and interaction strengths via a Monte-Carlo approach.

Overall, we find that the interactions tend to destabilize the network, with cascading failures occurring in 41% of cases in warming scenarios up to 2°C. More specifically, we uncover that:

(i) With increasing coupling strength, the temperature thresholds for inducing critical transitions are lowered significantly for West Antarctica, AMOC, ENSO and the Amazon rainforest. The dampening feedback loop between the Greenland Ice Sheet and the AMOC due to increased freshwater flux on the one hand and relative cooling around Greenland on the other, leads to an enhanced ambivalency whether the Greenland Ice Sheet tips or not.

(ii) Furthermore, our analysis reveals the role of each of the five tipping elements showing that the polar ice sheets on Greenland and West Antarctica are oftentimes the initiators of tipping cascades (in up to 40% of ensemble members for Greenland), while the AMOC acts as a mediator, transmitting cascades.

This implies that the ice sheets, which are already at risk of transgressing their temperature thresholds within the Paris range of 1.5 to 2°C, are of particular importance for the stability of the climate system as a whole.

How to cite: Wunderling, N., Donges, J., Kurths, J., and Winkelmann, R.: Interacting tipping elements increase risk of climate domino effects, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5412, https://doi.org/10.5194/egusphere-egu2020-5412, 2020

D2309 |
EGU2020-5920
Valerie Livina

We analyse proxy and observed data of atmospheric oxygen (ten contemporary records over the globe) and demonstrate its nonlinear decline, which is small but of uncertain decline rate. This decline was previously thought to be linear and caused mainly by use of fossil fuels (combustion), but by reviewing anthropogenic interventions we list more than a dozen smaller-scale processes that utilise oxygen in various forms. We have identified and quantified a previously unaccounted sink of atmospheric oxygen that serves multiple industries. This sink grows nonlinearly and has already exceeded the natural weathering deoxygenation. It has also been confirmed by means of comparison of the projection of oxygen decline with carbon emissions in the IPCC scenarios. We discuss the updated oxygen budget, possible solutions for the mitigation of the oxygen sink, and future dynamics of atmospheric oxygen.

[1] Livina et al, Tipping point analysis of atmospheric oxygen concentration, Chaos 25, 036403 (2015).

[2] Livina & Vaz Martins, The future of atmospheric oxygen, Springer Nature, in press.

 

How to cite: Livina, V.: Dynamics of atmospheric oxygen under anthropogenic stresses, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5920, https://doi.org/10.5194/egusphere-egu2020-5920, 2020

D2310 |
EGU2020-6655
Zengchao Hao, Fanghua Hao, and Xuan Zhang

Extremes, such as droughts, floods, heatwaves, and cold waves, may trigger large impacts on human society and the environment. The concurrent or consecutive occurrences of these extreme events (i.e., compound events) may result in even larger impacts than those caused by isolated extremes. Compound weather and climate extremes have attracted much attention in recent decades due to their disastrous impacts on the environment, ecosystem, and socioeconomics. It is thus of particular importance to improve our understanding of their properties, mechanisms, and impacts. Different methods for analyzing compound events and their impacts have been developed in recent decades. In this study, we introduce an R package for statistical modeling and analysis of compound events using compound precipitation and temperature extreme as examples. There are multiple components in this package, including the characterization, driver assessments, prediction, attribution, and impacts of compound events. For example, after extracting compound events based on the threshold of each variable, the package can be employed to assess the driving factors of compound events and predict their occurrences. The impact of compound events on different sectors (e.g., crop yield, vegetation) can also be assessed based on the multivariate model embedded in this package. This package is expected to be useful for compound events modeling and analysis for both researchers and decision-makers.

How to cite: Hao, Z., Hao, F., and Zhang, X.: CompoundEvents: An R package for statistical modeling of compound climate and weather events and their impacts , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6655, https://doi.org/10.5194/egusphere-egu2020-6655, 2020

D2311 |
EGU2020-8572
Jakob Zscheischler, Olivia Martius, Seth Westra, Emanuele Bevacqua, Colin Raymond, Radley Horton, Bart van den Hurk, Amir AghaKouchak, Aglaé Jézéquel, Miguel Mahecha, Douglas Maraun, Alexandre Ramos, Nina Ridder, Wim Thiery, and Edoardo Vignotto

Weather- and climate-related extreme events such as droughts, heatwaves and storms arise from interactions between complex sets of physical processes across multiple spatial and temporal scales, often overwhelming the capacity of natural and/or human systems to cope. In many cases, the greatest impacts arise through the ‘compounding’ effect of weather and climate-related drivers and/or hazards, where the scale of the impacts can be much greater than if any of the drivers or hazards occur in isolation; for instance, when a heavy precipitation falls on an already saturated soil causing a devastating flood. Compounding in this context refers to the amplification of an impact due to the occurrence of multiple drivers and/or hazards either because multiple hazards occur at the same time, previous climate conditions or weather events have increased a system’s vulnerability to a successive event, or spatially concurrent hazards lead to a regionally or globally integrated impact. More generally, compound weather and climate events refer to a combination of multiple climate drivers and/or hazards that contributes to societal or environmental risk.

Although many climate-related disasters are caused by compound events, our ability to understand, analyse and project these events and interactions between their drivers is still in its infancy. Here we review the current state of knowledge on compound events and propose a typology to synthesize the available literature and guide future research. We organize the highly diverse event types broadly along four main themes, namely preconditioned, multivariate, temporally compounding, and spatially compounding events. We highlight promising analytical approaches tailored to the different event types, which will aid future research and pave the way to a coherent framework for compound event analysis. We further illustrate how human-induced climate change affects different aspects of compound events, such as their frequency and intensity through variations in the mean, variability, and the dependence between their climatic drivers. Finally, we discuss the emergence of new types of events that may become highly relevant in a warmer climate.

How to cite: Zscheischler, J., Martius, O., Westra, S., Bevacqua, E., Raymond, C., Horton, R., van den Hurk, B., AghaKouchak, A., Jézéquel, A., Mahecha, M., Maraun, D., Ramos, A., Ridder, N., Thiery, W., and Vignotto, E.: A typology of compound weather and climate events, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8572, https://doi.org/10.5194/egusphere-egu2020-8572, 2020

D2312 |
EGU2020-8745
Anne Sophie Daloz, Johanne Rydsaa, Øivind Hodnebrog, Jana Sillmann, Bob van Oort, Christian Mohr, Madhoolika Agrawal, Lisa Emberson, Frøde Stordal, Tianyi Zhang, and Nathalie Schaller

The Sustainable Development Goals (SDGs) were adopted by all United Nations members states in 2015. “Erase hunger” and “Establish good health and well-being” are part of these goals and have major implications for agriculture and raises the question of how agriculture will be impacted by climate change. This work focuses on the potential impacts of the changing climate for agriculture, using the example of wheat yield in the Indo-Gangetic Plain (IGP) in India. First, the potential future changes in temperature and precipitation are examined over the IGP in regional climate simulations. The results show an increase in mean temperature and precipitation as well as maximum temperature during the growing season or Rabi season (November-April). Then, the direct (via temperature and precipitation) and indirect (via limiting irrigation) impacts of climate change on wheat yield are derived with a crop model for four selected sites in different states of the IGP (Punjab, Haryana, Uttar Pradesh and Bihar). The chosen sites are spread across the region to represent its major wheat growing areas.

The direct impact of climate change leads to wheat yield losses between -1% and -8% depending on the site examined and the irrigation regime chosen (6, 5, 3 or 1 irrigations). In this experiment, the number of irrigations remain the same in present and future climate. Then, when including the indirect impact of climate change the losses become much higher, reaching -4% to -36% depending on the site examined and by how much the irrigation is limited. This work shows the sensitivity of wheat yield to direct and indirect impacts of climate change in the IGP. It also emphasizes the complexity of climatic risk and the necessity of integrating more indirect impacts of climate change to fully assess how it affects agriculture.

How to cite: Daloz, A. S., Rydsaa, J., Hodnebrog, Ø., Sillmann, J., van Oort, B., Mohr, C., Agrawal, M., Emberson, L., Stordal, F., Zhang, T., and Schaller, N.: Direct and indirect impacts of climate change on wheat yield in the Indo-Gangetic plain in India, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8745, https://doi.org/10.5194/egusphere-egu2020-8745, 2020

D2313 |
EGU2020-8910
Thea Wübbelmann, Steffen Bender, and Benjamin Burkhard

Extreme weather events, failure of climate-change mitigation and adaptation, and biodiversity loss and ecosystem collapse are some of the main global risks. Climate change is one of the major drivers for ecosystem and biodiversity loss as well as for higher frequency and intensity of natural disasters and extreme weather events. Consequently, ecosystem health and the provision of ecosystem services (ES) is affected by the increasing pressures.

However, the provision of ecosystems must be ensured in order to guarantee and maintain human well-being. To define the benefits that people obtain from ecosystems there exist the concept of ES that links social and environmental systems to achieve sustainable use and discover trade-offs between different ES.

With respect to the increasing number of flood events (pluvial and fluvial) and of affected persons in the last years, one important key ES under external pressure is flood regulation. It describes the capacity to reduce flood hazards. Amongst other factors, climate change has a high impact on flood characteristics. Currently, most studies analyse the present status of flood regulating ES. Changing climate conditions and associated functionalities of the flood regulating ES are mostly not taken into account. This study shows the importance of assessing the current and future functionalities of flood regulating ES. In order to adapt ecosystems and their functionalities to projected climate impacts, it is important to consider regional climate information in the estimation process for flood regulating ES.

How to cite: Wübbelmann, T., Bender, S., and Burkhard, B.: The relevance of climate information in the assessment of flood regulating ecosystem services, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8910, https://doi.org/10.5194/egusphere-egu2020-8910, 2020

D2314 |
EGU2020-8957
Guangwei Zhu, Wenyi Da, Mengyuan Zhu, and Wei Li

The tail of reservoir is the un-stable zone in water quality and phytoplankton community. Therefore, it is the crucial zone in aquatic ecosystem transition. To understand the transition characteristics and driving mechanisms of water environment dynamics, eighteen months high frequent monitoring of water environment and phytoplankton community in tail of a deep and large reservoir, Xin'anjiang Reservoir in southeast of China, were undertaken by water quality monitoring buoy and 3-days interval water sampling. The result showed that, there are clearly seasonal thermal and oxygen stratification in the river mouth of the reservoir. The nutrient and chlorophyll-a concentrations also show stratifying phenomenon during thermal stratification period. Heavy rain and inflow will shortly destroy the stratification. Nutrient concentrations were high dynamic in the river mouth. Total phosphorus ranges among 0.011 mg·L-1 to 0.188 mg·L-1, and total nitrogen ranges among 0.75 mg·L-1 to 2.76 mg·L-1. The dissolved phosphorus occupied 56% of total phosphorus, and dissolved nitrogen occupied 88% of total nitrogen, respectively. Nutrient concentrations influenced strongly by rainfall intensity and inflow rate. Total phosphorus and nitrogen concentrations were significantly related to 3-days accumulated rainfall. Nutrient concentration in flood season (March to June) was significantly high than non-flood season (P

How to cite: Zhu, G., Da, W., Zhu, M., and Li, W.: Dynamics of water quality and phytoplankton community driving by extreme inflow in a huge drinking water source reservoir, China, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8957, https://doi.org/10.5194/egusphere-egu2020-8957, 2020

D2315 |
EGU2020-9501
Arun Rana, David N. Bresch, Annette Detken, and Maxime Souvignet

Climate Change has presented an ongoing and eminent threat to various regions, communities and infrastructure worldwide and in-turn increasingly pressuring national and local governments to take action. In the current study we identify and evaluate climate impacts faced by the city of Can Tho in Vietnam and the broader Mekong Delta and appraise preparedness options to manage today’s as well as future climate risk. We first, identify the climate risks in co-operation with various local, national and international stakeholders in the region. This is done on the current and future time scales under Socio-Economic Pathways (SSPs) as suggested in the current iteration of IPCC evaluation process. Based on these development pathways, we apply the Economics of Climate Adaptation (ECA) methodology to quantify the climate risks various sectors of the economy will be facing until 2050 with a focus on flood. Further we assess a range of possible adaption measures - including behavioral, environmental, physical as well as financial measures that can mitigate the identified risks by providing a cost-benefit analysis for each of the adaptation measures as well as for bundles thereof. The ECA methodology has proven to be an established tool to enhance our knowledge on the topic and its application in this specific context will enable stakeholders to strengthen societal resilience in the context of both socio-economic development and climate change.

How to cite: Rana, A., Bresch, D. N., Detken, A., and Souvignet, M.: Strengthening climate-resilience in the Mekong Delta – an application of the Economics of Climate Adaption (ECA) methodology, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9501, https://doi.org/10.5194/egusphere-egu2020-9501, 2020

D2316 |
EGU2020-9517
Torsten Weber, Paul Bowyer, Diana Rechid, Susanne Pfeifer, Francesca Raffaele, Armelle Reca Remedio, Claas Teichmann, and Daniela Jacob

The African population is already exposed to climate extremes such as droughts, heat waves and extreme precipitation, which cause damage to agriculture and infrastructure, and affect people's well-being. However, the simultaneous or sequential occurrence of two single climate extremes (compound event) has a more severe impact on the population and economy than single climate extremes. This circumstance is exacerbated by the increase in the African population, which is expected to double by the middle of this century according to the UN Department of Economic and Social Affairs (DESA). Currently, little is known about the potential future change in the occurrence of compound climate extremes and population exposed to these events in Africa. This knowledge is however needed by stakeholder and decision makers to develop measures for adaptation.

This research analyzes the occurrence of compound climate extremes such as droughts, heat waves and extreme precipitation in Africa under two different emission scenarios for the end of the century. For the analysis, we applied regional climate projections from the newly performed Coordinated Output for Regional Evaluations (CORE) embedded in the WCRP Coordinated Regional Climate Downscaling Experiment (CORDEX) Framework for Africa at a grid spacing of 25 km, and spatial maps of population projections derived from two different Shared Socioeconomic Pathways (SSPs). In order to take into account a low and a high emission scenario, the Representative Concentration Pathways (RCPs) 2.6 and 8.5 were used in the regional climate projections.

We will show that compound climate extremes are projected to be more frequent in Africa under the high emission scenario at the end of the century, and an increase in total exposure is primarily expected for West Africa, Central-East Africa and South-East Africa. Furthermore, combined impacts of population growth and increase in frequencies of compound extremes play an important role in the change of total exposure.

How to cite: Weber, T., Bowyer, P., Rechid, D., Pfeifer, S., Raffaele, F., Remedio, A. R., Teichmann, C., and Jacob, D.: Future compound climate extremes and exposed population in Africa, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9517, https://doi.org/10.5194/egusphere-egu2020-9517, 2020

D2317 |
EGU2020-11387
Kilian Kuhla, Sven Willner, Christian Otto, Tobias Geiger, and Anders Levermann

Weather extremes such as heat waves, tropical cyclones and river floods are likely to intensify with increasing global mean temperature. In a globally connected supply and trade network such extreme weather events cause economic shocks that may interfere with each other potentially amplifying their overall economic impact.

Here we analyze the economic resonance of concurrent extreme events, that is the overlapping of economic response dynamics of more than one extreme event category both spatially and temporally. In our analysis we focus on the event categories heat stress, river floods and tropical cyclones. We simulate the regional (direct) and global (indirect via supply chains) economic losses and gains for each extreme event category individually as well as for their concurrent occurrence for the next two decades. Thus we compare the outcome of the sum of the three single simulations to the outcome of the concurrent simulation. Here we show that the global welfare loss due to concurrent weather extremes is increased by more than 17% due to market effects compared to the summation of the losses of each single event category. Overall, this economic resonance yields a non-linearly enhanced price effect, which leads to a stronger economic impact. As well as a highly heterogeneous distribution of the amplification of regional welfare losses among countries.

Our analysis is based on the climate models of the CMIP5 ensemble which have been bias-corrected within the ISIMIP2b project towards an observation-based data set using a trend-preserving method. From these we use RCP2.6 and 6.0 for future climate projections. We transfer the three extreme weather event categories to a daily, regional and sectoral production failure. Our agent-based dynamic economic loss-propagation model Acclimate then uses these local production failures to compute the immediate response dynamics within the global supply chain as well as the subsequent trade adjustments. The Acclimate model thereby depicts a highly interconnected network of firms and consumers, which maximize their profits by choosing the optimal production level and corresponding upstream demand as well as the optimal distribution of this demand among its suppliers; transport and storage inventories act as buffers for supply shocks. The model accounts for local price changes, and supply and demand mismatches are resolved explicitly over time.

Our results suggest that economic impacts of weather extremes are larger than can be derived from conventional single event analysis. Consequently the societal cost of climate change are likely to be underestimated in studies focusing on single extreme categories.

How to cite: Kuhla, K., Willner, S., Otto, C., Geiger, T., and Levermann, A.: Single vs. concurrent extreme events: Economic resonance of weather extremes increases impact on societal welfare loss, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11387, https://doi.org/10.5194/egusphere-egu2020-11387, 2020

D2318 |
EGU2020-11543
Maral Habibi, Wolfgang Schöner, and Iman Babaeian

Abstract

In this study, droughts were assessed for the Uremia Lake Basin located in the North West of Iran which is facing the risk of drying over the last decades. Since long-term and spatially dense observational data are not available, in particular for the mountainous part of the Uremia lake basin, we successfully tested the performance of the ERA5 reanalysis data set for our purpose. By comparing time series plots of drought indices (SPI, SPEI), both indices were able to capture the temporal variation of droughts. SPIE identified more drought events but SPI, as it uses precipitation only as input, fails to show the increasing number of evaporation driven droughts in the Uremia Lake Basin, which were observed in particular for the most recent decade. SPEI was calculated using the monthly temperature and precipitation, the extremely dry conditions of the basin were observed in the mountainous area, it seems that based on SPEI index, the highest values of actual evapotranspiration happens near the lake and in high mountains. Moreover, in recent years, drought has become more extreme in higher elevated areas, then we focused on Snow cover which has a significant role in surface runoff and groundwater recharge in mountainous and semi-arid areas, like within the Uremia lake basin. In recent years climate change impact snow variations distribution, snow cover, and runoff in different scales. Therefore, spatial and temporal monitoring of the snow-covered surface and the impact of these changes is necessary. Consequently, the chances of snow cover (SCA) in the study area were studied using MODIS images by the NDSI index and snow cover data from the ERA5 dataset. Finally, we came to this conclusion that the temperature rise in recent decades led to a high amount of evaporation and consequently the snow surface area has decreased so that it could affect the region’s water reservoir in the future.

Key words: Drought monitoring,ERA5,MODIS,SPI,SPEI,NDSI

How to cite: Habibi, M., Schöner, W., and Babaeian, I.: Drought monitoring Using Standardized Precipitation Index (SPI), Standardized Precipitation-Evapotranspiration Index (SPEI) and Normalized-Difference Snow Index (NDSI) with observational and ERA5 dataset, within the uremia lake basin, Iran, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11543, https://doi.org/10.5194/egusphere-egu2020-11543, 2020

D2319 |
EGU2020-12141
Yi Yin, Branden Byrne, Junjie Liu, Paul Wennberg, Philipp Köhler, Vincent Humphrey, Troy Magney, Kenneth Davis, Tobias Gerken, Sha Feng, Joshua Digangi, and Christian Frankenberg

While large-scale floods directly impact human lives and infrastructures, they also profoundly impact agricultural productivity. New satellite observations of vegetation activity and atmospheric CO2 offer the opportunity to quantify the effects of such extreme events on cropland carbon sequestration, which are important for mitigation strategies. Widespread flooding during spring and early summer 2019 delayed crop planting across the U.S. Midwest. As a result, satellite observations of solar-induced chlorophyll fluorescence (SIF) from TROPOspheric Monitoring Instrument (TROPOMI) and Orbiting Carbon Observatory (OCO-2) reveal a shift of 16 days in the seasonal cycle of photosynthetic activity relative to 2018, along with a 15% lower peak photosynthesis. We estimate the 2019 anomaly to have led to a reduction of -0.21 PgC in gross primary production (GPP) in June and July, partially compensated in August and September (+0.14 PgC). The extension of the 2019 growing season into late September is likely to have benefited from increased water availability and late-season temperature. Ultimately, this change is predicted to reduce the crop yield over most of the midwest Corn/Soy belt by ~15%. Using an atmospheric transport model, we show that a decline of ~0.1 PgC in the net carbon uptake during June and July is consistent with observed CO2 enhancements from Atmospheric Carbon and Transport - America (ACT-America) aircraft and OCO-2. This study quantifies the impact of floods on cropland productivity and demonstrates the potential of combining SIF with atmospheric CO2 observations to monitor regional carbon flux anomalies.

How to cite: Yin, Y., Byrne, B., Liu, J., Wennberg, P., Köhler, P., Humphrey, V., Magney, T., Davis, K., Gerken, T., Feng, S., Digangi, J., and Frankenberg, C.: Cropland carbon uptake delayed by 2019 U.S. Midwest floods, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12141, https://doi.org/10.5194/egusphere-egu2020-12141, 2020

D2320 |
EGU2020-12451
Tiexi Chen

Extreme weather events have a severe impact on vegetation and the carbon cycle. It is generally believed that the vegetation will begin to recover immediately after the extremes, slowly or rapidly. This study will initially report a new response mechanism. We investigated a case of an extreme precipitation event that occurred in a double-cropping (DC) systems dominated region located Yangtze-Huai plain in China, where winter crops and summer crops are planted rotationally within one year. Generally October and June are the transitional periods for harvesting and sowing. In October 2016, monthly precipitation showed strong positive anomalies. Strong negative anomalies of EVI (enhanced vegetation index) persisted during March to May 2017, in response to the farmland abundance due to the heavy rain, especially over the farmland with winter crops – summer rice paddy systems. Information on abandonment due to precipitation also has been confirmed in local agro-meteorological monthly reports and some local government announcements. Data from a flux observation station in the region showed that from January to May 2017, NEE dropped significantly compared to the same period in 2016. Our results demonstrate that, in such a double-cropping system, once extreme events occur during the key sowing period and the phenological conditions determine that it cannot be replanted after, the duration of the impact will last through the entire crop growth period until the next sowing. In other word, land management could extend the duration of the impact of extremes on vegetation.

How to cite: Chen, T.: Land management extends the duration of the impact of extreme on vegetation, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12451, https://doi.org/10.5194/egusphere-egu2020-12451, 2020

D2321 |
EGU2020-13375
Paulo Bernardino, Wanda De Keersmaecker, Rasmus Fensholt, Jan Verbesselt, Ben Somers, and Stephanie Horion

Ecosystems in drylands are highly susceptible to changes in their way of functioning due to extreme and prolonged droughts or anthropogenic perturbation. Long-standing pressure, from climate or human action, may result in severe alterations in their dynamics. Moreover, changes in dryland ecosystems functioning can take place abruptly (Horion et al., 2016). Such abrupt changes may have severe ecological and economic consequences, disturbing the livelihood of drylands inhabitants and causing increased poverty and food insecurity. Considering that drylands cover 40% of Earth’s land surface and are home to around one-third of the human population, detecting and characterizing hotspots of abrupt changes in ecosystem functioning (here called turning points) becomes even more crucial.

BFAST, a time series segmentation technique, was used to detect breakpoints in time series (1982-2015) of rain-use efficiency. An abrupt change in rain-use efficiency time series points towards a significant change in the way an ecosystem responds to precipitation, allowing the study of turning points in ecosystem functioning in both natural and anthropogenic landscapes. Moreover, we here proposed a new typology to characterize turning points in ecosystem functioning, which takes into account the trend in ecosystem functioning before and after the turning point, as well as differences in the rate of change. Case studies were used to evaluate the performance of the new typology. Finally, ancillary data on population density and drought were used to have some first insights about the potential determinants of hotspots of turning point occurrence.

Our results showed that 13.6% of global drylands presented a turning point in ecosystem functioning between 1982 and 2015. Hotspots of turning point occurrence were observed in North America (where 62.6% of the turning points were characterized by a decreasing trend in ecosystem functioning), the Sahel, Central Asia, and Australia. The last three hotspot regions were mainly characterized by a positive trend in ecosystem functioning after the turning point. The ancillary data pointed to an influence of both droughts and human action on turning point occurrence in North America, while in Asia and Australia turning point occurrence was higher in areas with higher anthropogenic pressure. In the grasslands of the Sahel, turning points were potentially related to drought. 

By detecting where and when hotspots of turning points occurred in recent decades, and by characterizing the trends in ecosystem functioning before and after the turning points, we advanced towards better supporting decision making related to ecosystems conservation and management in drylands. Moreover, we provided first insights about the drivers of ecosystem functioning change in hotspots of turning point occurrence in global drylands (Bernardino et al., 2019).

 

References:

Bernardino PN, De Keersmaecker W, Fensholt R, Verbesselt J, Somers B, Horion S (2019) Global-scale characterization of turning points in arid and semi-arid ecosystems functioning. Manuscript submitted for publication.

Horion S, Prishchepov A V., Verbesselt J, de Beurs K, Tagesson T, Fensholt R (2016) Revealing turning points in ecosystem functioning over the Northern Eurasian agricultural frontier. Global change biology, 22, 2801–2817.

How to cite: Bernardino, P., De Keersmaecker, W., Fensholt, R., Verbesselt, J., Somers, B., and Horion, S.: Global-scale characterization of turning points in arid and semi-arid ecosystems functioning, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-13375, https://doi.org/10.5194/egusphere-egu2020-13375, 2020

D2322 |
EGU2020-18140
Ana Russo, Andreia Ribeiro, Célia M. Gouveia, and Carlos Pires

Droughts and hot extremes constitute key sources of risk to several socio-economic activities and human lives throughout the world, and their impacts can be exacerbated by their co-occurrence. Moreover, their occurrence is expected to increase under future global warming. Therefore, understanding the drought-heatwave feedback mechanisms is crucial for estimating the risk of impacts associated with their compound occurrence.

 

Several studies have examined individual extreme events or analyzed how intense certain events where. Nevertheless, limited research has explored drought-heatwave dependence, mostly focusing on the contribution of low antecedent soil moisture or preceding precipitation deficits to summer hot extremes. In the latest efforts in assessing the interactions between hot and dry extremes, the development of models describing the joint behaviour of climate extremes is still a challenge.

 

Here we propose to assess the probability of summer extremely hot days in the Iberian Peninsula (IP) being preceded by drought events in spring and early summer, based on their joint probability distribution through copula theory. Drought events were characterized by the Standardized Precipitation Evaporation Index (SPEI) for May, June and July for different timescales (3-, 6- and 9-months). The Number of Hot Days per month (NHD) summed over July and August were considered to characterize hot extremes.

 

Asymmetrical copulas with upper tail dependence were identified for the majority of the IP’s regions (except in northwestern regions), suggesting that compound hot and dry extremes are strongly associated. Moreover, the transition from previous wet to dry regimes increases substantially the probability of exceeding summer NHD extreme values. These results are region and time-scale dependent: 1) northeastern, western and central regions were found to be the regions more prone to summer hot extremes induced by dryness; 2) southwestern, northwestern and southeastern regions are less prone.

 

This assessment could be an important tool for responsible authorities to mitigate the impacts magnified by the interactions between the different hazards.

 

Acknowledgements: This work was supported by project IMPECAF (PTDC/CTA-CLI/28902/2017). Andreia Ribeiro thanks FCT for the grant PD/BD/114481/2016.

 

How to cite: Russo, A., Ribeiro, A., Gouveia, C. M., and Pires, C.: Assessment of drought and heat coupling during summer using copulas, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18140, https://doi.org/10.5194/egusphere-egu2020-18140, 2020

D2323 |
EGU2020-19561
Marc Wiedermann, E Keith Smith, Jonathan F Donges, Jobst Heitzig, and Ricarda Winkelmann

Social tipping, where minorities trigger large populations to engage in collective action, has been suggested as a key component to address contemporary global challenges, such as climate change or biodiversity loss. At the same time, certain climate tipping elements, such as the West Antarctic Ice Sheet, are already at risk of transgressing their critical thresholds, even within the aspired goals of the Paris Agreement to limit global temperature rise to 1.5° to 2°C. Consequently, recent studies suggest rapid societal transformations, i.e, wanted tipping, may be required to prevent the crossing of dangerous tipping points or critical thresholds in the climate system.

Here, we explore likelihoods for such social tipping in climate action as a response to anticipated climate impacts, particularly sea-level rise. We first propose a low-dimensional model for social tipping as a refined version of Granovetter's famous and well-established threshold model. This model assumes individuals to become active, e.g., to mitigate climate change, through social influence if a sufficient number of instigators in one’s social network initiate a considered action. We estimate the number of instigators as shares of per-country populations that will likely be impacted by sea-level rise within a given time-window of anticipation. Specifically, we consider sea-level contributions from thermal expansion, mountain glaciers, Greenland as well as Antarctica under different concentration pathways. Additionally, we use nationally aggregated social science survey data of climate change attitudes to estimate the proportion of the population that has the potential to be mobilized for climate action, thereby accounting for heterogeneities across countries as well.

Our model shows that social tipping, i.e., the majority of a population acting against climate change, becomes likely if the individuals' anticipation time horizon of climate impacts lies in the order of a century. This observation aligns well with ethical time horizons that are often assumed in the context of climate tipping points as they represent the expected lifetime of our children and grandchildren. We thus show that, even though sea-level rise is generally a very slow process, a small dedicated minority of anticipatory individuals – usually 10–20 percent of the population – has the potential to tip collective climate action and with it a whole ensemble of attitudes, behaviours and ultimately policies.

How to cite: Wiedermann, M., Smith, E. K., Donges, J. F., Heitzig, J., and Winkelmann, R.: Social tipping as a response to anticipated sea level rise, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19561, https://doi.org/10.5194/egusphere-egu2020-19561, 2020

D2324 |
EGU2020-19967
Carl-Friedrich Schleussner, Martha M. Vogel, Peter Pfleiderer, Marina Andrijevic, Friederike E. Otto, and Sonia I. Seneviratne

Heat extremes are among the most pertinent extreme weather hazards. At the same time, adaptation to the impacts of extreme heat can be very effective. The ability of societies to effectively adapt to climate change hazards such as extreme heat, however, critically depends on their level of socio-economic development. Examining the risks posed by future heat extremes to human societies requires to link socio-economic development trajectories with emerging heat extremes. Such an integrated assessment can also provide insights into whether or not it is indeed plausible for societies to “outgrow” climate change by increasing adaptive capacity faster than climate impacts emerge -  a narrative that underlies many policy decisions that prioritize economic development over climate action still today.

 

Here we provide such an integrated assessment by combining a novel approach to project the continuous emergence of heat extremes over the 21st century under different concentration pathways and the pace of socio-economic development under the shared socio-economic pathways accounting for continuous autonomous adaptation. We find that even under the most optimistic scenarios of future development, countries may not be able to outpace unmitigated climate change. Only Paris-Agreement compatible concentration pathways allow for human development to keep up with or even outpace the emerging climate change signal in vulnerable countries in the near future. A similar picture emerges when comparing heat day emergence with future evolution of governance as a proxy for adaptive capacity. Our findings underscore the critical importance of achieving the Paris Agreement goals to enable climate-resilient, sustainable development.

How to cite: Schleussner, C.-F., Vogel, M. M., Pfleiderer, P., Andrijevic, M., Otto, F. E., and Seneviratne, S. I.: Emerging heat extremes, adaptation and the speed of socio-economic development , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-19967, https://doi.org/10.5194/egusphere-egu2020-19967, 2020

D2325 |
EGU2020-20707
Paolo Ruggieri, Stefano Materia, Angel G. Muñoz, M.Carmen Alvarez Castro, Simon J. Mason, Frederic Vitart, and Silvio Gualdi

Producing probabilistic subseasonal forecasts of extreme events up to six weeks in advance is crucial for many economic sectors. In agribusiness, this time-scale is particularly critical because it allows for mitigation strategies to be adopted for counteracting weather hazards and taking advantage of opportunities.
For example, spring frosts are detrimental for many nut trees, resulting in dramatic losses at harvest time. To explore subseasonal forecast quality in boreal spring, identified as one of the most sensitive times of the year by agribusiness end-users, we build a multi-system ensemble using four models involved in the Subseasonal-to-Seasonal (S2S) Prediction Project. Two-meter temperature forecasts are used to analyze cold spell predictions in the coastal Black Sea region, an area that is a global leader in the production of hazelnuts. When analyzed at global scale, the multi-system ensemble probabilistic forecasts for near-surface temperature is better than climatological values for several regions, especially the Tropics, even many weeks in advance; however, in coastal Black Sea skill is low after the second forecast week. When cold spells are predicted instead of near-surface temperatures, skill improves for the region, and the forecasts prove to contain potentially useful information to stakeholders willing to put mitigation plans into effect. Using a cost-loss model approach for the first time in this context, we show that there is added value of having such a forecast system instead of a business-as-usual strategy, not only for predictions released one to two weeks ahead of the extreme event, but also at longer lead-times.

How to cite: Ruggieri, P., Materia, S., Muñoz, A. G., Alvarez Castro, M. C., Mason, S. J., Vitart, F., and Gualdi, S.: Multi-model subseasonal forecasts of spring cold spells: potential value for the hazelnut agribusiness, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20707, https://doi.org/10.5194/egusphere-egu2020-20707, 2020

D2326 |
EGU2020-6375
Takehito Yoshida

Natural disasters occur at an increasing rate probably due to the ongoing climate change, and adaptation to natural disaster risks is a key to the sustainability of local communities in Japan. At the same time, Japan is experiencing a rapid decline of human population and consequent aging. Ecosystem-based approaches to disaster risk reduction (Eco-DRR) takes advantage of the multi-functionality of ecosystems and biodiversity, including their capacity to mitigate natural disasters while providing multiple ecosystem services, and population decline provides ample opportunity for implementing Eco-DRR. We are developing practical solutions for implementation of Eco-DRR by visualizing natural disaster risks, evaluating multi-functionality of Eco-DRR solutions, conducting transdisciplinary approaches in collaboration with diverse stakeholders, and advocating traditional and local knowledge of disaster risk reduction. I will talk about some progress of our ongoing research project in RIHN (Research Institute for Humanity and Nature), Japan.

How to cite: Yoshida, T.: Ecosystem-based approaches to disaster risk reduction in Japan: transdisciplinary research and actions, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6375, https://doi.org/10.5194/egusphere-egu2020-6375, 2020