Effectively managing the rising health risks of climate change requires consideration of plausible adaptation pathways under a range of scenarios of changes in greenhouse gas emissions and socioeconomic development to systematically explore the solution space for climate-resilient health systems. Incorporating adaptation pathways approaches into health planning can facilitate understanding of adaptation opportunities, barriers, and limits by different degrees of warming (based on Representative Concentration Pathways (RCP) and levels of socioeconomic development (e.g., Shared Socioeconomic Pathways (SSP)). This understanding supports prioritization of policies and measures to reduce current and near-term risks, leading to more robust and timely health decisions. We explore how health adaptation pathways can be operationalized under the SSP framework to inform health system planning by: (i) identifying limits to adaptation (e.g., tipping dynamics where strategies are no longer feasible); (ii) illustrating timing and implementation delays, showing how deployment of health interventions may vary across development pathways; and (iii) exploring how multiple climate-sensitive health-related risks may stress health system capacity. Health decision makers can use the adaptation pathways approach in key activities such as vulnerability and adaptation assessments, developing health adaptation plans, and communication with interest holders, thereby strengthening preparedness and resilience for climate change.

Strengthening the connection between physical climate science and adaptation communities is essential for producing actionable, integrated risk information. Here we present a climate impact taxonomy linking 35 climatic impact-drivers to 8 representative key risks, with metadata on climate impact characteristics, relevant subsystems and adaptation–mitigation linkages. This prototype taxonomy enables researchers, practitioners and policymakers to develop adaptation strategies and direct support towards the most urgent, evidence-based priorities across IPCC-aligned dimensions. Adaptation to climate risks requires integrating knowledge across IPCC working groups. This study presents a climate impact taxonomy that connects climatic impact-drivers from Working Group I to representative key risks from Working Group II and provides more direct guidance for risk assessment and adaptation strategies.

Exceeding global warming of 1.5 °C in the near term is now unavoidable. An overshoot pathway, in which exceedance is followed by decline to or below the threshold through net-negative emissions, is now the only remaining route back to 1.5 °C. Permanent exceedance forecloses the recovery from climate impacts that an overshoot pathway may permit, yet even an overshoot pathway leaves lasting legacies. To characterise the reversibility of temporary overshoot impacts, we propose a three-layer analytical framework distinguishing hazards (with four dimensions: magnitude, duration, rate of exceedance, and rate of decline), biophysical responses (reversible vs persistent change), and socioeconomic outcomes (reversible vs irreversible impact). We introduce the socioeconomic commitment threshold, endogenous to the overshoot trajectory: how much overshoot intensity a system can experience before the losses it accumulates persist after temperatures decline, explained by three mechanisms: non-substitutability, threshold-crossing, and lock-in. A typology linking biophysical persistence with socioeconomic irreversibility illustrates how reversible biophysical change can produce irreversible socioeconomic loss, while persistent biophysical change need not produce irreversible outcomes where adaptive capacity is sufficient. Whether temporary exceedance produces permanent harm is determined primarily by socioeconomic rather than biophysical factors, except where permanent biophysical change exceeds adaptation limits. For systems and communities with low adaptive capacity, overshoot concentrates irreversible legacies even where temperatures subsequently decline, placing equity and justice at the centre of overshoot assessment.

For over a decade, the Shared Socioeconomic Pathways (SSPs) have served as the principal framework for quantitative modeling of the socioeconomic dimensions of global environmental change. The SSP scenarios describe many of the ecological and social processes thought to shape pandemic risk, including the emergence of novel pathogens (accelerated by processes such as deforestation, livestock intensification, and land-use change) and their subsequent spread (mediated by factors such as inequality, human mobility, and health system capacity). However, the SSP framework has not been widely incorporated into pandemic risk assessment. Here, we assess how pandemic risk is embedded in the SSP framework, and find that the framework captures most of the social-environmental drivers of pathogen spillover, and many of the social-economic drivers of pandemic spread and impacts. Because climate change and pandemics share many drivers and risk factors-- including ecosystem degradation, animal agriculture, and weak governance--SSP scenarios characterized by higher barriers to climate adaptation also generally imply lower chances of outbreak containment, and greater pandemic impacts on vulnerable populations. Pandemic risk is therefore lowest in SSP1 and highest in SSP3, but SSP5 shows that frequent spillover and effective containment can coexist. These findings suggest that pandemic risk can be understood as part of a broader polycrisis, linking climate change, biodiversity loss, and global health. We suggest that new scenario extensions, or entirely novel frameworks, will ultimately be needed to capture possible shifts in the global health landscape; however, in the meantime, scenario frameworks from the environmental sciences could be valuable tools for initiatives to quantify future pandemic risks.

Achieving universal drinking water and sanitation access by 2030 (SDG 6) remains uncertain under future socioeconomic and climate conditions. This study projects access to improved services using a logit-based model that incorporates income distribution, settlement structure, governance, and hydroclimatic indicators along SSP–RCP scenarios and estimates the associated water and energy footprint of closing the access gap. Results show that universal access is not achieved by 2030 in any scenario, with about 296 (±10%) million people lacking drinking water access. By the end of the century, access improves but remains incomplete, with about 250 million people without sanitation and 85 million without drinking water. Long-term projections reveal persistent regional disparities: access gaps remain concentrated in Sub-Saharan Africa and South Asia throughout the century. Scenarios characterized by persistent socioeconomic inequality (SSP3) show stagnation or increasing gaps, whereas more prosperous pathways (SSP1 and SSP5) achieve substantially faster progress but do not fully eliminate disparities. Closing remaining gaps implies substantial regional infrastructure expansion and additional water and energy demand—on the order of several km³ of water per year and up to 19.6 TWh/year globally by mid-century—highlighting the need for long-term, region-specific planning strategies.

Climate action is shaped as much by politics as by technology and economics. The Shared Socioeconomic Pathways (SSPs), central to mitigation and adaptation assessments, do not yet include a quantitative representation of political development. We outline a research agenda to systematically integrate political dimensions into climate scenario modelling.

Digital transformation refers to the widespread use of digital technologies in ways that reshape societal and economic activity, with significant impacts on sustainable development and climate challenges—both for better and for worse. Using statistical models calibrated to historical evidence in 62 countries across 12 world regions, we project future digital transformation within the Shared Socioeconomic Pathways (SSPs), adding contextual richness to this scenario framework used extensively in global climate research. In some scenarios, we find a pervasive and prolonged digital divide with up to 45% of the assessed population by mid-century still residing in countries with relatively low levels of digital transformation despite ever-deepening digitalisation in wealthier countries. We set out six use cases for how our explicit representation of digital transformation within the SSPs enables quantitative assessment of digitalisation’s impact on energy, emissions, climate policy, and Sustainable Development Goals. We also discuss challenges with using empirically calibrated models to project digital transformation given its rapid evolution and socioeconomic implications.

Currently, most research explaining why countries lead or lag in climate policy assumes a problem-oriented perspective, focusing on barriers to climate policy adoption. Here, we argue that correcting for past failures, solving problems, and bringing climate policies back on track for the Paris Agreement requires a solution-oriented perspective on the political enablers of ambitious climate policies. We unite a growing research community that has previously been scattered across disciplinary subfields with various ontological and epistemological assumptions. Rooted in a thematic review of the scientific literature, we introduce a framework with a typology of six political enablers for ambitious climate policy at its core. For each enabler, we summarize key policy implications. We illustrate our framework with a case study on the adoption of emission trading systems in the transport and building sectors in Germany and the European Union (EU) allowing future solution-oriented research to build on our effort.