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- ItemOur future in the Anthropocene biosphere(Dordrecht : Springer Netherlands, 2021) Folke, Carl; Polasky, Stephen; Rockström, Johan; Galaz, Victor; Westley, Frances; Lamont, Michèle; Scheffer, Marten; Österblom, Henrik; Carpenter, Stephen R.; Chapin, F. Stuart; Seto, Karen C.; Weber, Elke U.; Crona, Beatrice I.; Daily, Gretchen C.; Dasgupta, Partha; Gaffney, Owen; Gordon, Line J.; Hoff, Holger; Levin, Simon A.; Lubchenco, Jane; Steffen, Will; Walker, Brian H.The COVID-19 pandemic has exposed an interconnected and tightly coupled globalized world in rapid change. This article sets the scientific stage for understanding and responding to such change for global sustainability and resilient societies. We provide a systemic overview of the current situation where people and nature are dynamically intertwined and embedded in the biosphere, placing shocks and extreme events as part of this dynamic; humanity has become the major force in shaping the future of the Earth system as a whole; and the scale and pace of the human dimension have caused climate change, rapid loss of biodiversity, growing inequalities, and loss of resilience to deal with uncertainty and surprise. Taken together, human actions are challenging the biosphere foundation for a prosperous development of civilizations. The Anthropocene reality—of rising system-wide turbulence—calls for transformative change towards sustainable futures. Emerging technologies, social innovations, broader shifts in cultural repertoires, as well as a diverse portfolio of active stewardship of human actions in support of a resilient biosphere are highlighted as essential parts of such transformations. © 2021, The Author(s).
- ItemSocial tipping dynamics for stabilizing Earth's climate by 2050(2020) Otto, Ilona M.; Donges, Jonathan F.; Cremades, Roger; Bhowmik, Avit; Hewitt, Richard J.; Lucht, Wolfgang; Rockström, Johan; Allerberger, Franziska; McCaffrey, Mark; Doe, Sylvanus S.P.; Lenferna, Alex; Morán, Nerea; van Vuuren, Detlef P.; Schellnhuber, Hans JoachimSafely achieving the goals of the Paris Climate Agreement requires a worldwide transformation to carbon-neutral societies within the next 30 y. 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 socioeconomic 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 STIs that could trigger the tipping of STE subsystems include 1) removing fossil-fuel subsidies and incentivizing decentralized energy generation (STE1, energy production and storage systems), 2) building carbon-neutral cities (STE2, human settlements), 3) divesting from assets linked to fossil fuels (STE3, financial markets), 4) revealing the moral implications of fossil fuels (STE4, norms and value systems), 5) strengthening climate education and engagement (STE5, education system), and 6) 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.
- ItemHysteresis of tropical forests in the 21st century([London] : Nature Publishing Group UK, 2020) Staal, Arie; Fetzer, Ingo; Wang-Erlandsson, Lan; Bosmans, Joyce H. C.; Dekker, Stefan C.; van Nes, Egbert H.; Rockström, Johan; Tuinenburg, Obbe A.Tropical forests modify the conditions they depend on through feedbacks at 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 determine 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 geographic 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 currently lacks resilience, but is predicted to gain 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.
- ItemRootzone storage capacity reveals drought coping strategies along rainforest-savanna transitions(Bristol : IOP Publ., 2020) Singh, Chandrakant; Wang-Erlandsson, Lan; Fetzer, Ingo; Rockström, Johan; van der Ent, RuudClimate change and deforestation have increased the risk of drought-induced forest-to-savanna transitions across the tropics and subtropics. However, the present understanding of forest-savanna transitions is generally focused on the influence of rainfall and fire regime changes, but does not take into account the adaptability of vegetation to droughts by utilizing subsoil moisture in a quantifiable metric. Using rootzone storage capacity (Sr), which is a novel metric to represent the vegetation's ability to utilize subsoil moisture storage and tree cover (TC), we analyze and quantify the occurrence of these forest-savanna transitions along transects in South America and Africa. We found forest-savanna transition thresholds to occur around a Sr of 550–750 mm for South America and 400–600 mm for Africa in the range of 30%–40% TC. Analysis of empirical and statistical patterns allowed us to classify the ecosystem's adaptability to droughts into four classes of drought coping strategies: lowly water-stressed forest (shallow roots, high TC), moderately water-stressed forest (investing in Sr, high TC), highly water-stressed forest (trade-off between investments in Sr and TC) and savanna-grassland regime (competitive rooting strategy, low TC). The insights from this study are useful for improved understanding of tropical eco-hydrological adaptation, drought coping strategies, and forest ecosystem regime shifts under future climate change.
- ItemAll options, not silver bullets, needed to limit global warming to 1.5 °C: a scenario appraisal(Bristol : IOP Publ., 2021-5-25) Warszawski, Lila; Kriegler, Elmar; Lenton, Timothy M.; Gaffney, Owen; Jacob, Daniela; Klingenfeld, Daniel; Koide, Ryu; Máñez Costa, María; Messner, Dirk; Nakicenovic, Nebojsa; Schellnhuber, Hans Joachim; Schlosser, Peter; Takeuchi, Kazuhiko; Van Der Leeuw, Sander; Whiteman, Gail; Rockström, JohanClimate science provides strong evidence of the necessity of limiting global warming to 1.5 °C, in line with the Paris Climate Agreement. The IPCC 1.5 °C special report (SR1.5) presents 414 emissions scenarios modelled for the report, of which around 50 are classified as '1.5 °C scenarios', with no or low temperature overshoot. These emission scenarios differ in their reliance on individual mitigation levers, including reduction of global energy demand, decarbonisation of energy production, development of land-management systems, and the pace and scale of deploying carbon dioxide removal (CDR) technologies. The reliance of 1.5 °C scenarios on these levers needs to be critically assessed in light of the potentials of the relevant technologies and roll-out plans. We use a set of five parameters to bundle and characterise the mitigation levers employed in the SR1.5 1.5 °C scenarios. For each of these levers, we draw on the literature to define 'medium' and 'high' upper bounds that delineate between their 'reasonable', 'challenging' and 'speculative' use by mid century. We do not find any 1.5 °C scenarios that stay within all medium upper bounds on the five mitigation levers. Scenarios most frequently 'over use' CDR with geological storage as a mitigation lever, whilst reductions of energy demand and carbon intensity of energy production are 'over used' less frequently. If we allow mitigation levers to be employed up to our high upper bounds, we are left with 22 of the SR1.5 1.5 °C scenarios with no or low overshoot. The scenarios that fulfil these criteria are characterised by greater coverage of the available mitigation levers than those scenarios that exceed at least one of the high upper bounds. When excluding the two scenarios that exceed the SR1.5 carbon budget for limiting global warming to 1.5 °C, this subset of 1.5 °C scenarios shows a range of 15–22 Gt CO2 (16–22 Gt CO2 interquartile range) for emissions in 2030. For the year of reaching net zero CO2 emissions the range is 2039–2061 (2049–2057 interquartile range).
- ItemIdentifying a Safe and Just Corridor for People and the Planet(Hoboken, NJ : Wiley-Blackwell, 2021) Rockström, Johan; Gupta, Joyeeta; Lenton, Timothy M.; Qin, Dahe; Lade, Steven J.; Abrams, Jesse F.; Jacobson, Lisa; Rocha, Juan C.; Zimm, Caroline; Bai, Xuemei; Bala, Govindasamy; Bringezu, Stefan; Broadgate, Wendy; Bunn, Stuart E.; DeClerck, Fabrice; Ebi, Kristie L.; Gong, Peng; Gordon, Chris; Kanie, Norichika; Liverman, Diana M.; Nakicenovic, Nebojsa; Obura, David; Ramanathan, Veerabhadran; Verburg, Peter H.; van Vuuren, Detlef P.; Winkelmann, RicardaKeeping the Earth system in a stable and resilient state, to safeguard Earth's life support systems while ensuring that Earth's benefits, risks, and related responsibilities are equitably shared, constitutes the grand challenge for human development in the Anthropocene. Here, we describe a framework that the recently formed Earth Commission will use to define and quantify target ranges for a “safe and just corridor” that meets these goals. Although “safe” and “just” Earth system targets are interrelated, we see safe as primarily referring to a stable Earth system and just targets as being associated with meeting human needs and reducing exposure to risks. To align safe and just dimensions, we propose to address the equity dimensions of each safe target for Earth system regulating systems and processes. The more stringent of the safe or just target ranges then defines the corridor. Identifying levers of social transformation aimed at meeting the safe and just targets and challenges associated with translating the corridor to actors at multiple scales present scope for future work.
- ItemIs wetter better? Exploring agriculturally-relevant rainfall characteristics over four decades in the Sahel(Bristol : IOP Publ., 2021-2-11) Porkka, Miina; Wang-Erlandsson, Lan; Destouni, Georgia; Ekman, Annica M. L.; Rockström, Johan; Gordon, Line J.The semi-arid Sahel is a global hotspot for poverty and malnutrition. Rainfed agriculture is the main source of food and income, making the well-being of rural population highly sensitive to rainfall variability. Studies have reported an upward trend in annual precipitation in the Sahel since the drought of the 1970s and early ‘80s, yet farmers have questioned improvements in conditions for agriculture, suggesting that intraseasonal dynamics play a crucial role. Using high-resolution daily precipitation data spanning 1981–2017 and focusing on agriculturally-relevant areas of the Sahel, we re-examined the extent of rainfall increase and investigated whether the increases have been accompanied by changes in two aspects of intraseasonal variability that have relevance for agriculture: rainy season duration and occurrence of prolonged dry spells during vulnerable crop growth stages. We found that annual rainfall increased across 56% of the region, but remained largely the same elsewhere. Rainy season duration increased almost exclusively in areas with upward trends in annual precipitation (23% of them). Association between annual rain and dry spell occurrence was less clear: increasing and decreasing frequencies of false starts (dry spells after first rains) and post-floral dry spells (towards the end of the season) were found to almost equal extent both in areas with positive and those with no significant trend in annual precipitation. Overall, improvements in at least two of the three intraseasonal variables (and no declines in any) were found in 10% of the region, while over a half of the area experienced declines in at least one intraseasonal variable, or no improvement in any. We conclude that rainfall conditions for agriculture have improved overall only in scattered areas across the Sahel since the 1980s, and increased annual rainfall is only weakly, if at all, associated with changes in the agriculturally-relevant intraseasonal rainfall characteristics.
- ItemTen new insights in climate science 2020 – a horizon scan(Cambridge : Cambridge University Press, 2021) Pihl, Erik; Alfredsson, Eva; Bengtsson, Magnus; Bowen, Kathryn J.; Cástan Broto, Vanesa; Chou, Kuei Tien; Cleugh, Helen; Ebi, Kristie; Edwards, Clea M.; Fisher, Eleanor; Friedlingstein, Pierre; Godoy-Faúndez, Alex; Gupta, Mukesh; Harrington, Alexandra R.; Hayes, Katie; Hayward, Bronwyn M.; Hebden, Sophie R.; Hickmann, Thomas; Hugelius, Gustaf; Ilyina, Tatiana; Jackson, Robert B.; Keenan, Trevor F.; Lambino, Ria A.; Leuzinger, Sebastian; Malmaeus, Mikael; McDonald, Robert I.; McMichael, Celia; Miller, Clark A.; Muratori, Matteo; Nagabhatla, Nidhi; Nagendra, Harini; Passarello, Cristian; Penuelas, Josep; Pongratz, Julia; Rockström, Johan; Romero-Lankao, Patricia; Roy, Joyashree; Scaife, Adam A.; Schlosser, Peter; Schuur, Edward; Scobie, Michelle; Sherwood, Steven C.; Sioen, Giles B.; Skovgaard, Jakob; Sobenes Obregon, Edgardo A.; Sonntag, Sebastian; Spangenberg, Joachim H.; Spijkers, Otto; Srivastava, Leena; Stammer, Detlef B.; Torres, Pedro H. C.; Turetsky, Merritt R.; Ukkola, Anna M.; van Vuuren, Detlef P.; Voigt, Christina; Wannous, Chadia; Zelinka, Mark D.Non-technical summary: We summarize some of the past year's most important findings within climate change-related research. New research has improved our understanding of Earth's sensitivity to carbon dioxide, finds that permafrost thaw could release more carbon emissions than expected and that the uptake of carbon in tropical ecosystems is weakening. Adverse impacts on human society include increasing water shortages and impacts on mental health. Options for solutions emerge from rethinking economic models, rights-based litigation, strengthened governance systems and a new social contract. The disruption caused by COVID-19 could be seized as an opportunity for positive change, directing economic stimulus towards sustainable investments. Technical summary: A synthesis is made of ten fields within climate science where there have been significant advances since mid-2019, through an expert elicitation process with broad disciplinary scope. Findings include: (1) a better understanding of equilibrium climate sensitivity; (2) abrupt thaw as an accelerator of carbon release from permafrost; (3) changes to global and regional land carbon sinks; (4) impacts of climate change on water crises, including equity perspectives; (5) adverse effects on mental health from climate change; (6) immediate effects on climate of the COVID-19 pandemic and requirements for recovery packages to deliver on the Paris Agreement; (7) suggested long-term changes to governance and a social contract to address climate change, learning from the current pandemic, (8) updated positive cost-benefit ratio and new perspectives on the potential for green growth in the short- A nd long-term perspective; (9) urban electrification as a strategy to move towards low-carbon energy systems and (10) rights-based litigation as an increasingly important method to address climate change, with recent clarifications on the legal standing and representation of future generations. Social media summary: Stronger permafrost thaw, COVID-19 effects and growing mental health impacts among highlights of latest climate science. Copyright © The Author(s), 2021. Published by Cambridge University Press.
- ItemAssessment of the growth in social groups for sustainable agriculture and land management(Cambridge : Cambridge Univ. Press, 2020) Pretty, Jules; Attwood, Simon; Bawden, Richard; van den Berg, Henk; Bharucha, Zareen P.; Dixon, John; Butler Flora, Cornelia; Gallagher, Kevin; Genskow, Ken; Hartley, Sue E.; Ketelaar, Jan Willem; Kiara, Japhet K.; Kumar, Vijay; Lu, Yuelai; MacMillan, Tom; Maréchal, Anne; Morales-Abubakar, Alma Linda; Noble, Andrew; Prasad, P. V. Vara; Rametsteiner, Ewald; Reganold, John; Ricks, Jacob I.; Rockström, Johan; Saito, Osamu; Thorne, Peter; Wang, Songliang; Wittman, Hannah; Winter, Michael; Yang, PuyunNon-technical summary Until the past half-century, all agriculture and land management was framed by local institutions strong in social capital. But neoliberal forms of development came to undermine existing structures, thus reducing sustainability and equity. The past 20 years, though, have seen the deliberate establishment of more than 8 million new social groups across the world. This restructuring and growth of rural social capital within specific territories is leading to increased productivity of agricultural and land management systems, with particular benefits for those previously excluded. Further growth would occur with more national and regional policy support. Technical summary For agriculture and land management to improve natural capital over whole landscapes, social cooperation has long been required. The political economy of the later twentieth and early twenty-first centuries prioritized unfettered individual action over the collective, and many rural institutions were harmed or destroyed. Since then, a wide range of social movements, networks and federations have emerged to support transitions towards sustainability and equity. Here, we focus on social capital manifested as intentionally formed collaborative groups within specific geographic territories. These groups focus on: (1) integrated pest management; (2) forests; (3) land; (4) water; (5) pastures; (6) support services; (7) innovation platforms; and (8) small-scale systems. We show across 122 initiatives in 55 countries that the number of groups has grown from 0.50 million (in 2000) to 8.54 million (in 2020). The area of land transformed by the 170–255 million group members is 300 Mha, mostly in less-developed countries (98% groups; 94% area). Farmers and land managers working with scientists and extensionists in these groups have improved both environmental outcomes and agricultural productivity. In some cases, changes to national or regional policy supported this growth in groups. Together with other movements, these social groups could now support further transitions towards policies and behaviours for global sustainability. Social media summary Millions of geographically based new social groups are leading to more sustainable agriculture and forestry worldwide. © The Author(s), 2020.
- ItemCorona and the climate: A comparison of two emergencies(Cambridge : Cambridge Univ. Press, 2020) Vinke, Kira; Gabrysch, Sabine; Paoletti, Emanuela; Rockström, Johan; Schellnhuber, Hans JoachimSocial media summary Lessons from the corona crisis can help manage the even more daunting challenge of anthropogenic global warming. © The Author(s), 2020.