The Chicxulub asteroid impact at the Cretaceous-Paleogene (K-Pg) boundary (66 Ma) is thought to have caused the extinction of around 75% of species in the fossil record by triggering catastrophic environmental changes1. However, despite decades of research, the mechanisms linking the environmental changes to the selective extinction patterns observed in the marine fossil record remain unresolved. Here we use a global trait-based ecosystem model2,3 to establish this causality for the marine plankton community beyond the fossilized groups. Our model simulates diversity dynamics during the initial 100 years after the K-Pg boundary and represents explicitly extinction based on biomass thresholds that scales with body size. Under K-Pg climatic forcings, the model reproduces successfully key observed extinction patterns, including the high vulnerability of planktic foraminifera and other zooplankton, the survival of small mixotrophs4 and phytoplankton5,6, and potential for reduced diversity loss in high-latitude settings7. Our analysis suggests that impact-driven darkness and body-size-dependent extinction thresholds drove most of the observed extinction patterns. These results suggest that plankton ecologies enhance survival through differences in energy demand and acquisition. Our study bridges the gap between fossil evidence of extinction patterns and the K-Pg impact winter hypothesis, highlighting the value of trait-based models for understanding past biodiversity crises.

The carbonate clumped isotope paleothermometer is becoming more widely used in the geosciences because it is less sensitive to solution delta O-18 and Mg/Ca than other carbonate-based temperature proxies. Here, we examine the impacts of dissolution on foraminiferal clumped isotope records (Delta(47)). Dissolution is known to impact carbonate minerals in ocean sediments near and below the carbonate saturation horizon. The effects of dissolution on foraminiferal mass, delta O-18, and Mg/Ca have been the subject of prior work but have not yet been reported for the carbonate clumped isotope paleothermometer. We examine six planktic foraminiferal species from core-tops collected at different water depths on the Ontong Java Plateau. Below the carbonate saturation horizon, multiple species exhibit higher Delta(47) values, biasing Delta(47) to cooler temperatures, though all species remain within error of their assumed calcification depth ranges. These effects are observed in Globigerinella siphonifera, Pulleniatina obliquiloculata, and Globorotalia tumida with an similar to 0.01 parts per thousand difference from above to below the saturation horizon; p < 0.01 corresponding to a temperature bias of similar to 4 degrees C at a measured temperature of 28 degrees C and of similar to 3 degrees C at a measured temperature of 18 degrees C. Normalizing data for different species yields a pooled slope of -0.0006 parts per thousand/mu mol/kg Delta[CO32-] (p < 0.01). Dissolution experiments show that for two species, Trilobus sacculifer and G. tumida, Delta(47) increased with mass loss. We propose multiple mechanisms by which dissolution may impact Delta(47) including intra-test heterogeneous dissolution, which provide context to enable corrections for the impacts of dissolution on clumped isotope-based paleo-records.

The EECO (-53-49 Ma) is characterized by the highest global average temperature and CO2 levels of the Cenozoic, providing the opportunity to explore the interplay between prolonged warmth, potential physiological stress, and marine planktic ecosystems, of which planktic foraminifera are a component. Previous studies have documented a dramatic decline in the dominant planktic foraminiferal genus Morozovella and a concurrent increase in Acarinina abundances at the onset of the EECO in the Atlantic, Tethys and Pacific Oceans. This study aims to investigate how extreme climatic conditions during the EECO influenced the abundance, size, and ecological strategies of planktic foraminifera, focusing on the response of the symbiont-bearing mixed-layer dweller Morozovella and Acarinina at Ocean Drilling Program (ODP) sites 1209-1210 Shatsky Rise, in the subtropical Pacific Ocean. We present species abundances, test size and delta 13C data of Morozovella. Acarinina test size and delta 13C data were quantified to assess whether observed changes affected all mixed-layer dwellers or were specific to Morozovella. Our results show a temporary increase in Morozovella test size at the EECO onset, partially linked to the dominance of larger species such as M. crater and M. aragonensis. In contrast, Acarinina displays a reduction in test size. The generally lower delta 13C values across the EECO in Acarinina suggest a deeper habitat in the mixedlayer and/or reduced symbiosis relative to Morozovella. We speculate that Acarinina evaded the high temperatures by moving deeper in the mixed layer. The reduced symbiosis relationship due to diminished light in the deeper water column might have led to a smaller test size. In contrast, Morozovella maintained a shallower position in the mixed layer allowing it to sustain efficient symbiosis and larger size. However, the limited ecological flexibility of this taxon may have impeded its ability to adapt and maintain high abundance across the EECO.

Planktic foraminifera are key producers of pelagic carbonate, and their shell weight is suggested to have been influenced by the environment in which they calcify. However, there is debate about the use of size-normalised weight (SNW) as a proxy, as some authors invoke a carbonate system control on calcification (and by extension SNW as a pCO2 proxy), while others suggest that species optimum conditions, nutrient concentration, or temperature drive shell weight. To better understand this proxy, we investigate what drives SNW and whether discrepancies in the proposed control on weight are due to differing data collection methodologies and/or regionally different drivers. We integrate new and published SNW data with environmental hindcast data from the CMIP6 modelling suite. Using Bayesian regression modelling, we find that the environment alone does not explain the variability in SNW across species. Although physiology likely modulates the response to the environment, we find little evidence of a unifying driver at the ecogroup level. Instead, we identify species-specific responses associated with drivers including (but not limited to) the carbonate system, which are likely different between ocean basins. We hypothesise that this is partly influenced by cryptic species and regional phenotypic plasticity in changes to shell weight that are not well understood, such as the thickness of calcite deposited during some species' reproductive phases. Consequently, which species to use as a pCO2 proxy or whether multiple species should be used in parallel to reduce uncertainty should be carefully considered. We strongly encourage the regional testing and calibration of pCO2–SNW relationships.

The Cenozoic shift from a hothouse to icehouse provides a natural experiment to explore how a changing climate and macroevolutionary trends control marine pelagic carbonate production and burial. In the modern ocean, the key components of pelagic carbonate burial — planktic foraminifera and coccolithophores — contribute approximately evenly. However, in the past, coccolithophores dominated open ocean inorganic carbon burial. Exactly when and why this shift away from a coccolithophore dominated ooze occurred is unresolved. To this end, we reconstructed a 65Myr record of foraminifer to nannofossil ratios from sites covering the Pacific, Southern, Indian, and Atlantic Ocean. To better understand the climate and macroevolutionary controls on carbonate production, we move away from the commonly reported bulk changes and instead investigate the individual components of carbonate production: foraminiferal and coccolithophore size, weight and abundance. We use a suite of methodologies to extract these data, including the novel application of imaging flow cytometry to rapidly and digitally reconstruct the fossil record of coccolithophore size and abundance. Our ratio data shows a shift towards calcareous zooplankton during the Neogene. Initial qualitative analysis reveals that coccolithophore size is relatively smaller in the modern part of the record, whilst automated microscopy shows that modern subtropical and tropical foraminiferal size is greater than recorded in the previous 65Myr. Foraminiferal size-normalised weight (SNW) is expected to be higher in the modern ocean than in the past due to its suggested carbonate system control (i.e. higher carbonate ion concentrations being conducive to heavier tests). However, SNW data from a high latitude site during the Palaeogene are similar to modern values for extant species – potentially implying something other than a carbonate system control on SNW.

Planktic foraminifera are a major contributor to global marine inorganic carbon production. They leave abundant calcium carbonate shells on the seafloor that serve as prime proxies for the physical and chemical attributes of past oceans. Despite their well-preserved fossil record and widespread use in palaeoceanography, our understanding of their ecology remains limited due to their low-standing stocks in the modern ocean and the challenges in culturing multiple generations under laboratory conditions, even after decades of data collection. This limitation affects our ability to interpret their fossil remains to describe past ecosystems and predict their responses to ongoing environmental changes. Trait-based ecology offers a powerful framework to characterise how and why foraminifera interact with their environment. Here, we review the current state of knowledge on key planktic foraminifera traits, including morphological, physiological, behavioural, and life history traits. Most spinose taxa are carnivorous, host to dinoflagellate photosymbionts, and are abundant and diverse in oligotrophic environments. In contrast, non-spinose taxa are typically herbivorous and most common in high-productivity regions. We highlight the potential of trait modelling to generate hypotheses testable in the field. Integration of trait-based modelling with metabarcoding, environmental DNA, and enhanced standardised data collection made openly available will help to fill critical gaps in our understanding of planktic foraminiferal ecology and allow us to use foraminifera as a key model organism for addressing fundamental ecological questions.

Past warm events offer windows into the biotic response to extreme warmth. The early Eocene interval records the highest global average temperature and CO2 levels of the Cenozoic. Several transient global warming events occur within the Early Eocene Climatic Optimum (EECO, 53-49 Ma), offering an opportunity to investigate the impact of both long term and transient warm climatic conditions on planktic foraminifera. We analyse the planktic foraminiferal record across the EECO obtained from tropical Pacific ODP sites 1209-1210 (Shatsky Rise). These sites have an excellent age model and stable isotope ratios enabling linkage of the biotic data with the climate and carbon cycle spanning the EECO.We combine indicators of carbonate production and preservation [fragmentation index (FI) as a dissolution proxy, weight percent coarse fraction (CF) as foraminiferal production and preservation index, and Foraminiferal Mass Accumulation Rate (FMAR) as foraminiferal production proxy] with changes in planktic foraminiferal assemblages and test-size.At the EECO onset, the abundance of the genus Morozovella (53.28 Ma) and Chiloguembelina (52.85 Ma) decreased at Shatsky Rise sites, confirming previous Atlantic Ocean data and thus pointing towards global decline of these genera. We hypothesise that a reduction in foraminiferal mass accumulation and assemblage test-size would follow the drop in Morozovellids abundance, given their dominance and large size in early Eocene tropical assemblages. In contrast, we record a slight increase in test-size within assemblages and a relatively stable FMAR. These changes may be controlled by growing dominance of the genus Acarinina indicating an ability of this species to benefit from the environmental conditions. In addition, we observe a relatively stable FMAR at decreasing CF which may be linked to either increased carbonate dissolution or enhanced calcareous nannofossil productivity (or a combination of both) reducing foraminiferal relative contribution to the sediment.Even though the pronounced warming during the EECO strongly altered the planktic foraminiferal assemblage composition resulting in the decrease in abundance of some genera, species replacement within communities highlights the resilience of pelagic carbonate production.

Plain Language SummaryThe Early Eocene Climatic Optimum (EECO) is an interval of prolonged warmth that occurred ∼53 to 49 million years ago. Planktic foraminifera are important (alongside coccolithophores) for understanding the carbon cycle and determining export production in the ocean. To understand how foraminifera can be impacted by extreme heat, we analyzed samples from the Pacific Ocean through measuring changes in (a) the relative abundance, that is, the count of different taxa in a sample, and (b) body (shell) size of planktic foraminifera. At the start of the EECO, the abundance of the genera Morozovella and Chiloguembelina decreased. Despite this decline, the number of foraminifera being buried and the size of the largest shells in a sample does not change. We attribute this to the increased abundance of the genus Acarinina. In general, the accumulation of foraminifera remains stable while the relative abundance of foraminifera to coccolithophores decreases. Together, this implies that coccolithophores are increasing in abundance, and/or mass. During the EECO, one group of foraminifera was able to counterbalance the decrease in abundance of other genera. This highlights the resilience of open‐ocean carbonate production and the base of the marine food web.

Climate related changes are already affecting every area of our world and will increasingly do so as global warming increases, resulting in compounding and cascading risks across multiple locations and sectors. Deliberative processes and anticipatory actions are required to adapt to the associated complex and uncertain systemic risks, with dynamic and long-term planning needed even where there is limited knowledge of the effectiveness of adaptation. In this focus article, we examine the adaptation pathways developed for the Europe Chapter of the IPCC AR6. We argue that illustrative pathways built on quantitative and qualitative assessment of adaptation effectiveness can inform adaptation planning to manage the increasing severity of risks. We find that as the global warming level increases adaptation pathways can diverge, leading to radically different futures, for example, adaptation responses to sea level rise. We illustrate how adaptation measures for different risks interact resulting in trade-offs, for example, increasing water scarcity. Although pathways offer a useful framework to address multiple adaptation challenges, other supporting conditions are needed for the successful implementation of adaptation, such as establishing legitimacy and buy-in through collaboration of various actors and effective governance. Ultimately, adaptation will be increasingly more complex and constrained in a warmer world, increasing risks of losses and damages to people and nature.

The impacts of climate change on marine organisms have been increasingly documented in laboratory and experimental studies. However, the use of different taxonomic groupings and the assessment of a range of processes make identifying overall trends challenging. Meta-analysis has been used to determine general trends, but coarse taxonomic granularity may mask phylogenetically specific responses. Bivalve molluscs are a data-rich clade of ecologically and economically important calcifying marine taxa that allow for the assessment of species-specific vulnerability across developmental stages. Drawing on the large body of available literature, we conduct a meta-analysis of 203 unique experimental set-ups in order to examine how bivalve growth responds to increased water temperature, acidity, deoxygenation, and changes in salinity in 10 climate change stressor combinations. This is the most complete examination of bivalve responses to date and shows that anthropogenic climate change will disproportionally affect particular families, suggesting taxonomic differentiation in climate change response. Specifically, Mytilidae, Ostreidae, and Pectinidae (67 % of experiments) respond with negative effect sizes for all individual stressors, whereas responses in Pinnidae, Tellinidae, and Veneridae are more complex. Our analysis shows that earlier studies reporting negative impacts on bivalves are driven by only three or four well-studied, commercially important families. Despite the taxonomic differentiation, almost all drivers and their combinations have significant negative effects on growth. The synergistic impacts of deoxygenation, acidification, and temperature result in the largest negative effect size. Infaunal taxa, including Tellinidae and Veneridae, appear more resistant to warming and oxygen reduction than epifaunal or motile taxa, but this difference between the two taxa is also based on a small number of data points. The current focus of experimental set-ups on commercially important taxa and families within a small geographic range creates gaps in the understanding of global impacts on these economically important foundation organisms.

Weather and climate patterns play an intrinsic role in societal health, yet a comprehensive synthesis of specific hazard-mortality causes does not currently exist. Country-level health burdens are thus highly uncertain, but harnessing collective expert knowledge can reduce this uncertainty, and help assess diverse mortality causes beyond what is explicitly quantified. Here, surveying 30 experts, we provide the first structured expert judgement of how weather and climate directly impact mortality, using the UK as an example. Current weather-related mortality is dominated by short-term exposure to hot and cold temperatures leading to cardiovascular and respiratory failure. We find additional underappreciated health outcomes, especially related to long-exposure hazards, including heat-related renal disease, cold-related musculoskeletal health, and infectious diseases from compound hazards. We show potential future worsening of cause-specific mortality, including mental health from flooding or heat, and changes in infectious diseases. Ultimately, this work could serve to develop an expert-based understanding of the climate-related health burden in other countries.

Climate change affects marine organisms, causing migrations, biomass reduction and extinctions1,2. However, the abilities of marine species to adapt to these changes remain poorly constrained on both geological and anthropogenic timescales. Here we combine the fossil record and a global trait-based plankton model to study optimal temperatures of marine calcifying zooplankton (foraminifera, Rhizaria) through time. The results show that spinose foraminifera with algal symbionts acclimatized to deglacial warming at the end of the Last Glacial Maximum (LGM, 19-21 thousand years ago, ka), whereas foraminifera without symbionts (non-spinose or spinose) kept the same thermal preference and migrated polewards. However, when forcing the trait-based plankton model with rapid transient warming over the coming century (1.5 °C, 2 °C, 3 °C and 4 °C relative to pre-industrial baseline), the model suggests that the acclimatization capacities of all ecogroups are limited and insufficient to track warming rates. Therefore, foraminifera are projected to migrate polewards and reduce their global carbon biomass by 5.7-15.1% (depending on the warming) by 2100 relative to 1900-1950. Our study highlights the different challenges posed by anthropogenic and geological warming for marine plankton and their ecosystem functions.

Pronounced warming negatively impacts ecosystem resilience in modern oceans. To offer a long-term geological perspective of the calcareous plankton response to global warming, we present an integrated record, from two Tethyan sections (northeastern Italy), of the planktic foraminiferal and calcareous nannofossil response to the Eocene Thermal Maximum 2 hyperthermal (ETM2, similar to 54 Ma). Our study reveals pronounced changes in assemblage composition and a striking dwarfing of planktic foraminiferal tests of up to 40% during the event, impacting both surface and deeper dwellers. The increased abundance of small placoliths among calcareous nannofossils is interpreted as community size reduction. Literature and our foraminiferal size data from Sites 1263 and 1209 (Atlantic and Pacific Oceans) highlights that the pronounced dwarfism is restricted to the Tethyan area. The ETM2 is characterized by warm sea surface temperatures as indicated by our delta 18O data, but this warming is of global extent and cannot explain the unique dwarfism. Excluding evolutionary modifications, other potential drivers of dwarfism (eutrophication, deoxygenation, metabolic adaptation) cannot explain the exceptional dwarfism by themselves. The smallest sizes are in close temporal association with peaks in volcanic derived Hg/Th-Hg/Rb recorded just before and at the ETM2 which could not have been brought into our sections through weathering. In contrast, size reductions are absent below and above the ETM2 at Hg peaks where delta 18O data do not show warm conditions. We speculate that the local input of toxic metals from submarine volcanic emissions could have acted synergistically to warming, causing the unique dwarfism. Calcareous plankton size in the Tethys during the Eocene Thermal Maximum 2 (ETM2) reveals marked dwarfism Pronounced dwarfism was restricted to the Tethyan area, highlighting the importance of local signals in interpreting hyperthermals Calcareous plankton were highly unstable across the ETM2 but ultimately resilient

Visual as well as genetic biometrics are routinely employed to identify species and individuals in biological applications. However, no attempts have been made in this domain to computationally enhance visual classification of rare classes with little image data via genetics. In this paper, we thus propose aligned visual-genetic learning as a new application domain with the aim to implicitly encode cross-modality associations for improved performance. We demonstrate for the first time that such alignment can be achieved via deep embedding models and that the approach is directly applicable to boosting long-tailed recognition (LTR), particularly for rare species. We experimentally demonstrate the efficacy of the concept via application to microscopic imagery of 30k+ planktic foraminifer shells across 32 species when used together with independent genetic data samples. Most importantly for practitioners, we show that visual-genetic alignment can significantly benefit visual-only recognition of the rarest species. Technically, we pre-train a visual ResNet50 deep learning model using triplet loss formulations to create an initial embedding space. We re-structure this space based on genetic anchors embedded via a Sequence Graph Transform (SGT) and linked to visual data by cross-domain cosine alignment. We show that an LTR approach improves the state-of-the-art across all benchmarks and that adding our visual-genetic alignment improves per-class and particularly rare tail class benchmarks significantly further. Overall, visual-genetic LTR training raises rare per-class accuracy from 37.4% to benchmark-beating 59.7%. We conclude that visual-genetic alignment can be a highly effective tool for complementing visual biological data containing rare classes. The concept proposed may serve as an important future tool for integrating genetics and imageomics towards a more complete scientific representation of taxonomic spaces and life itself. Code, weights, and data splits are published for full reproducibility.

Background Local authorities have a crucial role in building community resilience to the health effects of a changing climate. Support in achieving local action can be provided through improving available public health intelligence to inform decision making. We aimed to co-develop with a local authority a tool mapping vulnerability to climate related hazards. Methods We conducted a feasibility study, exploring through stakeholder engagement local priorities and levers for action in adaptation that could be informed by provision of increased intelligence. This informed co-development of a proof-of-concept tool. Results Stakeholders reported needs in better understanding the intersection between vulnerability and hazard to facilitate partnership working, decision making, and targeting of interventions. We developed a mapping tool, using nationally available data, overlaying a vulnerability index with hazard (heat and flooding) exposure. Conclusions Mapping tools are feasible methods by which public health intelligence to support climate change adaptation planning can be shared. Barriers to action may result from the complexity of vulnerability, concerns of unintended consequences, and resource constraints. Co-development with local expertise is necessary to ensure that outputs add value to local response. This tool will now be piloted to gather feedback on useability, usefulness, and potential improvements.

Past warm events offer windows into the biotic response to extreme warmth. The early Eocene interval records the highest global average temperature and CO2 levels of the Cenozoic. Several transient global warming events occur within the Early Eocene Climatic Optimum (EECO, 53-49 Ma), offering an opportunity to investigate the impact of both long term and transient warm climatic conditions on planktic foraminifera. We analyse the planktic foraminiferal record across the EECO obtained from tropical Pacific ODP sites 1209-1210 (Shatsky Rise). These sites have an excellent age model and stable isotope ratios enabling linkage of the biotic data with the climate and carbon cycle spanning the EECO. We combine indicators of carbonate production and preservation [fragmentation index (FI) as a dissolution proxy, weight percent coarse fraction (CF) as foraminiferal production and preservation index, and Foraminiferal Mass Accumulation Rate (FMAR) as foraminiferal production proxy] with changes in planktic foraminiferal assemblages and test-size. At the EECO onset, the abundance of the genus Morozovella (53.28 Ma) and Chiloguembelina (52.85 Ma) decreased at Shatsky Rise sites, confirming previous Atlantic Ocean data and thus pointing towards global decline of these genera. We hypothesise that a reduction in foraminiferal mass accumulation and assemblage test-size would follow the drop in Morozovellids abundance, given their dominance and large size in early Eocene tropical assemblages. In contrast, we record a slight increase in test-size within assemblages and a relatively stable FMAR. These changes may be controlled by growing dominance of the genus Acarinina indicating an ability of this species to benefit from the environmental conditions. In addition, we observe a relatively stable FMAR at decreasing CF which may be linked to either increased carbonate dissolution or enhanced calcareous nannofossil productivity (or a combination of both) reducing foraminiferal relative contribution to the sediment. Even though the pronounced warming during the EECO strongly altered the planktic foraminiferal assemblage composition resulting in the decrease in abundance of some genera, species replacement within communities highlights the resilience of pelagic carbonate production.

Tipping points have gained substantial traction in climate change discourses. Here we critique the ‘tipping point’ framing for oversimplifying the diverse dynamics of complex natural and human systems and for conveying urgency without fostering a meaningful basis for climate action. Multiple social scientific frameworks suggest that the deep uncertainty and perceived abstractness of climate tipping points render them ineffective for triggering action and setting governance goals. The framing also promotes confusion between temperature-based policy benchmarks and properties of the climate system. In both natural and human systems, we advocate for clearer, more specific language to describe the phenomena labelled as tipping points and for critical evaluation of whether, how and why different framings can support scientific understanding and climate risk management. The tipping points framing is widely used in climate discussions but receives mixed feedback. This Perspective critiques it for oversimplifying the complexities of natural and social systems and failing to drive effective action, and offers recommendations for future improvements.

Climate change is predicted to negatively impact calcification and change the structural integrity of biogenic carbonates, influencing their protective function. We assess the impacts of warming on the morphology and crystallography of Amphistegina lobifera, an abundant benthic foraminifera species in shallow environments. Specimens from a thermally disturbed field area, mimicking future warming, are about 50% smaller compared with a control location. Differences in the position of the ν1 Raman mode of shells between the sites, which serves as a proxy for Mg content and calcification temperature, indicate that calcification is negatively impacted when temperatures are below the thermal range facilitating calcification. To test the impact of thermal stress on the Young's modulus of calcite which contributes to structural integrity, we quantify elasticity changes in large benthic foraminifera by applying atomic force microscopy to a different genus, Operculina ammonoides, cultured under optimal and high temperatures. Building on these observations of size and the sensitivity analysis for temperature-induced change in elasticity, we used finite element analysis to show that structural integrity is increased with reduced size and is largely insensitive to calcite elasticity. Our results indicate that warming-induced dwarfism creates shells that are more resistant to fracture because they are smaller.

The key risks assessment developed in the context of the IPCC Working Group II AR6 Europe chapter pulled together multiple line of evidence across the published literature and used expert elicitation to identify those risks with the greatest potential to become severe or that are already severe now. Four key risks have been identified for Europe, namely: 1) heat stress to human and ecosystems; 2) loss of agriculture productivity due to heat and dry conditions and extreme weather; 3) water scarcity to multiple interconnected sectors; 4) coastal and inland flooding. Alongside the assessment of the key risks, an assessment of the effectiveness of discrete adaptation options was also performed following a protocol which defines adaptation effectiveness as the risk reduction potential of an adaptation option from a given baseline. More than 50 discrete options were assessed with the greatest majority showing medium effectiveness to reduce risks. These two assessments have brought forward some critical aspects in adaptation decision making which have inspired further analysis. These aspects are 1) the need for long term planning, 2) the diversity of contexts within which adaptation takes place, 3) the existence of multiple interacting risks and 4) the limited knowledge on the effectiveness of adaptation as opposed to the knowledge on adaptation limits. We explore here the use of warming sensitive adaptation pathways as a framework to address these critical aspects and present reflections on how illustrative adaptation pathways can support effective decision making that also reduces the implementation gap. For example, our pathways framework points at a dichotomous future to reduce coastal flooding in the long term and a future where all options will be needed to reduce the risks of water scarcity. The framework also shows that considering multiple risks together under different levels of warming can inform adaptation decision making about potential constraints, trade-offs, and lock-ins. In general, for the illustrative adaptation pathways to be useful planning tools certain preconditions must be in place such as legitimacy through monitoring and evaluation as well as human and financial capital towards multiple and diverse pathways.