Search

Accessible, reliable, and diverse sources of climate information are needed to inform climate change adaptation at all levels of society, particularly for vulnerable sectors, such as smallholder farming. Globally, many smallholder farmers use Indigenous knowledge (IK) and local knowledge (LK) to forecast weather and climate; however, less is known about how the use of these forecasts connects to decisions and actions for reducing climate risks. We examined the role of IK and LK in seasonal forecasting and the broader climate adaptation decision-making of smallholder farmers in Chiredzi, Zimbabwe. The data were collected from a sample of 100 smallholder farmers. Seventy-three of the 100 interviewed farmers used IK and LK weather and climate forecasts, and 32% relied solely on IK and LK forecasts for climate adaptation decision-making. Observations of cuckoo birds, leaf-sprouting of Mopane trees, high summer temperatures, and Nimbus clouds are the main indicators used for IK and LK forecasts. The use of IK and LK climate forecasts was significantly positively associated with increasing farmer age and farmland size. Farmers using IK and LK forecasts implemented, on average, triple the number of adaptation measures compared with farmers not using IK and LK. These findings demonstrate the widespread reliance of farmers on IK and LK for seasonal forecasts, and the strong positive link between the use of IK and LK and the implementation of climate adaptation actions. This positive association between IK and LK usage and the implementation of adaptation actions may be widespread in smallholder farming communities throughout Africa and globally. Recognition and inclusion of IK and LK in climate services is important to ensure their continued potential for enhancing climate change adaptation.

Vulnerability to climate variability and change differs from one group to another, from sector to another, and between regions. Understanding the degree to which smallholder farmers are vulnerable to climate risk is critical when assessing adaptation responses to offset current and future risks. Here, we assessed the vulnerability of smallholder farmers to climate variability in Chiredzi, Zimbabwe. Vulnerability is assessed using a two-dimensional approach – quantitative analysis of observed climate data to assess farmers’ exposure and qualitative analysis of farmers’ socio-economic data. The Livelihood Vulnerability Index (LVI) is applied to understand levels of farmers’ livelihood vulnerability. 16 rainfall and temperature indices and extreme events critical to rainfed smallholder farmers were analysed at annual and seasonal scales from 1972–2021. A cross-sectional survey was conducted on 100 smallholder farmers. Our results confirm an increased warming trend, and forward shift of the rainy season onset, with both of these indices showing statistically significant trends. A maximum temperature increase of 0.1 oC annum-1 was observed. All the other indices and extreme events exhibited insignificant trends. The total seasonal rainfall has increased by 3.2 mm annum-1. Increased interseasonal variability of the measured indices was observed. Hot days for maize and sorghum have increased by 0.25 and 0.85 days annum-1 respectively. The combination of increased delayed rainy season onset and a decreasing trend for rainy season length suggests that the rainy season is shrinking slowly. There was alignment between farmers’ perceptions of the climate and trends from observed climate data on the majority (seven) of the indices. Livelihood vulnerability to climate risk varied for farmers in communal and resettled wards. Farmers in resettled areas had a higher LVI (0.4076) than farmers in communal areas (0.3762). The LVI-IPCC shows a relatively similar index for both communal and resettled wards (-0.0874 and -0.0849 respectively). Importantly, farmers with Indigenous knowledge (IK) and local knowledge (LK) background showed lower LVI than farmers without IK and LK, implying the important role of IK and LK, in climate vulnerability assessment and in increasing farmers’ adaptive capacity. Our results have implications on the implementation of climate adaptation responses by smallholder farmers in Chiredzi. Adaptation measures should be tailored based on the vulnerability levels of farmers and their exposure to climate risks. This is important for the implementation of effective climate adaptation responses in the Chiredzi district.

Under the United Nations Framework Convention on Climate Change, international financial assistance is expected to support African and other developing countries as they prepare for and adapt to the impacts of climate change. The impact of this finance depends on how much finance is mobilized and where it is targeted. However, there has been no comprehensive quantitative mapping of adaptation-related finance flows to African countries to date. Here we track development finance principally targeting adaptation from bilateral and multilateral funders to Africa between 2014 and 2018. We find that the amounts of finance are well below the scale of investment needed for adaptation in Africa, which is a region with high vulnerability to climate change and low adaptation capacity. Finance targeting mitigation (US$30.6 billion) was almost double that for adaptation (US$16.5 billion). The relative share of each varies greatly among African countries. More adaptation-related finance was provided as loans (57%) than grants (42%) and half the adaptation finance has targeted just two sectors: agriculture; and water supply and sanitation. Disbursement ratios for adaptation in this period are 46%, much lower than for total development finance in Africa (at 96%). These are all problematic patterns for Africa, highlighting that more adaptation finance and targeted efforts are needed to ensure that financial commitments translate into meaningful change on the ground for African communities. Key policy insightsBetween 2014 and 2018, adaptation-related finance committed by bilateral and multilateral funders to African countries remained well below US$5.5 billion per year, or roughly US$5 per person per year; these amounts are well below the estimates of adaptation costs in Africa.Funders have not strategically targeted support for adaptation activities towards the most vulnerable to climate change African countries.Lessons from countries that have been more successful in accessing finance point to the value of more sophisticated domestic adaptation policies and plans; of alignment with priorities of the NDC; of meeting funding requirements of specific funders; and of the strategic use of climate funds by national planners.A low adaptation finance disbursement ratio in this period in Africa (at 46%) relates to barriers impeding the full implementation of adaptation projects: low grant to loan ratio; requirements for co-financing; rigid rules of climate funds; and inadequate programming capacity within many countries. Between 2014 and 2018, adaptation-related finance committed by bilateral and multilateral funders to African countries remained well below US$5.5 billion per year, or roughly US$5 per person per year; these amounts are well below the estimates of adaptation costs in Africa. Funders have not strategically targeted support for adaptation activities towards the most vulnerable to climate change African countries. Lessons from countries that have been more successful in accessing finance point to the value of more sophisticated domestic adaptation policies and plans; of alignment with priorities of the NDC; of meeting funding requirements of specific funders; and of the strategic use of climate funds by national planners. A low adaptation finance disbursement ratio in this period in Africa (at 46%) relates to barriers impeding the full implementation of adaptation projects: low grant to loan ratio; requirements for co-financing; rigid rules of climate funds; and inadequate programming capacity within many countries.

Temperature overshoot pathways entail exceeding a specified global warming level (e.g. 1.5°C or 2°C) followed by a decline in warming, achieved through anthropogenically enhanced CO 2 removal from the atmosphere. However, risks to biodiversity from temperature overshoot pathways are poorly described. Here, we explore biodiversity risks from overshoot by synthesizing existing knowledge and quantifying the dynamics of exposure and de-exposure to potentially dangerous temperatures for more than 30 000 species for a 2°C overshoot scenario. Our results suggest that climate risk to biodiversity from temperature overshoot pathways will arrive suddenly, but decrease only gradually. Peak exposure for biodiversity occurs around the same time as peak global warming, but the rate of de-exposure lags behind the temperature decline. While the global overshoot period lasts around 60 years, the duration of elevated exposure of marine and terrestrial biodiversity is substantially longer (around 100 and 130 years, respectively), with some ecological communities never returning to pre-overshoot exposure levels. Key biodiversity impacts may be irreversible and reliance on widespread CO 2 removal to reduce warming poses additional risks to biodiversity through altered land use. Avoiding any temperature overshoot must be a priority for reducing biodiversity risks from climate change, followed by limiting the magnitude and duration of any overshoot. More integrated models that include direct and indirect impacts from overshoot are needed to inform policy. This article is part of the theme issue ‘Ecological complexity and the biosphere: the next 30 years’.

Ecological research and practice are crucial to understanding and guiding more positive relationships between people and ecosystems. However, ecology as a discipline and the diversity of those who call themselves ecologists have also been shaped and held back by often exclusionary Western approaches to knowing and doing ecology. To overcome these historical constraints and to make ecology inclusive of the diverse peoples inhabiting Earth’s varied ecosystems, ecologists must expand their knowledge, both in theory and practice, to incorporate varied perspectives, approaches and interpretations from, with and within the natural environment and across global systems. We outline five shifts that could help to transform academic ecological practice: decolonize your mind; know your histories; decolonize access; decolonize expertise; and practise ethical ecology in inclusive teams. We challenge the discipline to become more inclusive, creative and ethical at a moment when the perils of entrenched thinking have never been clearer. The authors outline five decolonizing shifts that could help to transform academic ecological practice, challenging the discipline to become more inclusive, creative and ethical.

Rapid urbanization and the global loss of biodiversity necessitate the development of a research agenda that addresses knowledge gaps in urban ecology that will inform policy, management, and conservation. To advance this goal, we present six topics to pursue in urban biodiversity research: the socioeconomic and social–ecological drivers of biodiversity loss versus gain of biodiversity; the response of biodiversity to technological change; biodiversity–ecosystem service relationships; urban areas as refugia for biodiversity; spatiotemporal dynamics of species, community changes, and underlying processes; and ecological networks. We discuss overarching considerations and offer a set of questions to inspire and support urban biodiversity research. In parallel, we advocate for communication and collaboration across many fields and disciplines in order to build capacity for urban biodiversity research, education, and practice. Taken together we note that urban areas will play an important role in addressing the global extinction crisis.

Accessible, reliable and diverse sources of climate information are needed to inform anticipatory responses to climate change at all levels of society, particularly for vulnerable sectors such as smallholder farming. Globally, many communities use Indigenous knowledge (IK) and local knowledge (LK) to provide contextually calibrated and trusted forecasting information to guide livelihood choices, including on-farm decisions by smallholder farmers. Here, we examined the role of IK and LK in seasonal forecasting, preparedness, and broader climate adaptation decision-making of smallholder farmers in Chiredzi, Zimbabwe. Data was collected from 100 smallholder farmers through face-to-face semi-structured interviews in the month before the rainy season onset when preparatory decisions about planting were being made. Seventy-three percent (73%) of the interviewed farmers are using IK and LK-based climate forecasts, and 32% (of 73%) farmers rely on IK and LK only for climate risk preparedness decision-making. Binary logistic regression found the use of IK and LK climate forecasts by farmers was strongly predicted by farmers’ age and farm size with p = 0.009 and 0.017 respectively at p

Tobias, Joseph A., Sheard, Catherine, Pigot, Alex L., Devenish, Adam J. M., Yang, Jingyi, Sayol, Ferran, Neate‐Clegg, Montague H. C., Alioravainen, Nico, Weeks, Thomas L., Barber, Robert A., Walkden, Patrick A., MacGregor, Hannah E. A., Jones, Samuel E. I., Vincent, Claire, Phillips, Anna G., Marples, Nicola M., Montaño‐Centellas, Flavia A., Leandro‐Silva, Victor, Claramunt, Santiago, Darski, Bianca, Freeman, Benjamin G., Bregman, Tom P., Cooney, Christopher R., Hughes, Emma C., Capp, Elliot J. R., Varley, Zoë K., Friedman, Nicholas R., Korntheuer, Heiko, Corrales‐Vargas, Andrea, Trisos, Christopher H., Weeks, Brian C., Hanz, Dagmar M., Töpfer, Till, Bravo, Gustavo A., Remeš, Vladimír, Nowak, Larissa, Carneiro, Lincoln S., Moncada R., Amilkar J., Matysioková, Beata, Baldassarre, Daniel T., Martínez‐Salinas, Alejandra, Wolfe, Jared D., Chapman, Philip M., Daly, Benjamin G., Sorensen, Marjorie C., Neu, Alexander, Ford, Michael A., Mayhew, Rebekah J., Fabio Silveira, Luis, Kelly, David J., Annorbah, Nathaniel N. D., Pollock, Henry S., Grabowska‐Zhang, Ada M., McEntee, Jay P., Carlos T. Gonzalez, Juan, Meneses, Camila G., Muñoz, Marcia C., Powell, Luke L., Jamie, Gabriel A., Matthews, Thomas J., Johnson, Oscar, Brito, Guilherme R. R., Zyskowski, Kristof, Crates, Ross, Harvey, Michael G., Jurado Zevallos, Maura, Hosner, Peter A., Bradfer‐Lawrence, Tom, Maley, James M., Stiles, F. Gary, Lima, Hevana S., Provost, Kaiya L., Chibesa, Moses, Mashao, Mmatjie, Howard, Jeffrey T., Mlamba, Edson, Chua, Marcus A. H., Li, Bicheng, Gómez, M. Isabel, García, Natalia C., Päckert, Martin, Fuchs, Jérôme, Ali, Jarome R., Derryberry, Elizabeth P., Carlson, Monica L., Urriza, Rolly C., Brzeski, Kristin E., Prawiradilaga, Dewi M., Rayner, Matt J., Miller, Eliot T., Bowie, Rauri C. K., Lafontaine, René‐Marie, Scofield, R. Paul, Lou, Yingqiang, Somarathna, Lankani, Lepage, Denis, Illif, Marshall, Neuschulz, Eike Lena, Templin, Mathias, Dehling, D. Matthias, Cooper, Jacob C., Pauwels, Olivier S. G., Analuddin, Kangkuso, Fjeldså, Jon, Seddon, Nathalie, Sweet, Paul R., DeClerck, Fabrice A. J., Naka, Luciano N., Brawn, Jeffrey D., Aleixo, Alexandre, Böhning‐Gaese, Katrin, Rahbek, Carsten, Fritz, Susanne A., Thomas, Gavin H., Schleuning, Matthias (2022): AVONET: morphological, ecological and geographical data for all birds. Ecology Letters 25 (3): 581-597, DOI: 10.1111/ele.13898, URL: http://dx.doi.org/10.1111/ele.13898

Animals have diversified into a bewildering variety of morphological forms exploiting a complex configuration of trophic niches. Their morphological diversity is widely used as an index of ecosystem function, but the extent to which animal traits predict trophic niches and associated ecological processes is unclear. Here we use the measurements of nine key morphological traits for >99% bird species to show that avian trophic diversity is described by a trait space with four dimensions. The position of species within this space maps with 70–85% accuracy onto major niche axes, including trophic level, dietary resource type and finer-scale variation in foraging behaviour. Phylogenetic analyses reveal that these form–function associations reflect convergence towards predictable trait combinations, indicating that morphological variation is organized into a limited set of dimensions by evolutionary adaptation. Our results establish the minimum dimensionality required for avian functional traits to predict subtle variation in trophic niches and provide a global framework for exploring the origin, function and conservation of bird diversity.

Climate change poses a threat to heritage globally. Decolonial approaches to climate change–heritage research and practice can begin to address systemic inequities, recognize the breadth of heritage and strengthen adaptation action globally.

Important heritage sites along the African coast are at risk from the threats associated with rising sea levels. Here, we quantify the exposure of natural and cultural heritage sites in Africa to coastal flooding and erosion in the 21st century. We develop a comprehensive database of 284 coastal African Heritage Sites (AHS), composed of 213 natural and 71 cultural heritage sites, which is then combined with coastal flooding and erosion projections to assess exposure to coastal extreme events for a moderate (RCP4.5) and high (RCP8.5) greenhouse gas emissions scenario. We find that 56 AHS are presently at risk from a 100-year extreme sea-level event, with a total exposed heritage area of 2,222 km2. Most of the currently exposed AHS are located in Northern and Western Africa. By mid-century, the number of exposed AHS is projected to increase more than 3 times to reach 191 and 198 under moderate and high emissions respectively. In the second half of the century, the number of exposed sites stabilizes, but the median exposed area increases to 6.6 to 8.5 times the present-day value, under moderate and high emissions, respectively. Mitigation from high to moderate emissions will reduce the end-century median exposed area and number of very highly exposed sites by 20% and 25% respectively.

Evidence of human adaptation actions responding to climate impacts is increasing in Africa. However, a holistic understanding of effective adaptation across the diversity of African contexts is still limited at a continental scale. Despite high reliance on indigenous knowledge (IK) and local knowledge (LK) for climate adaptation in Africa, the potential risk reduction of IK and LK and its role in supporting transformative adaptation responses is yet to be established. Here, we assess the influence of IK and LK on the implementation of water sector adaptation in Africa and describe the relationship between adaptation and indigenous and local knowledge systems. Eighteen (18) water sector response types were identified from the academic literature through the Global Adaptation Mapping Initiative (GAMI). The most implemented measures across Africa influenced by IK and LK were household-level and individual measures and included irrigation, rainwater harvesting, water conservation and ecosystem-based measures (mainly agroforestry). Southern, west, and east Africa show relatively high evidence of the influence of IK and LK on the implementation of water adaptation responses while north, and central Africa show lower evidence. At country level, Zimbabwe display highest evidence (77.8%) followed by Ghana (53.6%), Kenya (46.2%) and South Africa (31.3%). Adaptation responses with IK and LK influence recorded higher evidence of risk reduction compared to articles without IK and LK. Analysis of intended nationally determined contributions (iNDCs) shows the most implemented water adaptation actions in academic literature are consistent with water sector adaptation targets set by most African governments. Yet only 10.4% of the African governments included IK and LK in adaptation planning in the iNDCs. The study recommends a coordinated approach to adaptation that integrates multiple knowledge sources including IK and LK to ensure greater effectiveness and scalability of current and potential water adaptation measures in Africa.

Real-world experience underscores the complexity of interactions among multiple drivers of climate change risk and of how multiple risks compound or cascade. However, a holistic framework for assessing such complex climate change risks has not yet been achieved. Clarity is needed regarding the interactions that generate risk, including the role of adaptation and mitigation responses. In this perspective, we present a framework for three categories of increasingly complex climate change risk that focus on interactions among the multiple drivers of risk, as well as among multiple risks. A significant innovation is recognizing that risks can arise both from potential impacts due to climate change and from responses to climate change. This approach encourages thinking that traverses sectoral and regional boundaries and links physical and socio-economic drivers of risk. Advancing climate change risk assessment in these ways is essential for more informed decision making that reduces negative climate change impacts. © 2021 The Authors

Despite biological invasions are one of the main environmental problems of the twenty-first century, there is still no theoretical or empirical agreement on whether a high phylogenetic relatedness between exotic and native species positively or negatively affect invasion success. To resolve this conundrum, it has been proposed that the effect might be scale-dependent, being negative at smaller spatial scales and positive at larger scales. Here we show that this scale-dependent pattern may be a sampling artefact associated with species-area effects and a non-random pattern of species introductions. We support this conclusion with simulations and empirical data on invaded and non-invaded avian communities in regions from five continents. We further show that at smaller-scales —where these artifacts are negligible— invasion success generally increases with the presence of closely-related species, but that predictive accuracy largely depends on considering the influence of human-related disturbances in facilitating invasions.

We present the first systematic, global stocktake of the academic literature on human adaptation. We screen 48,316 documents and identify 1,682 articles that present empirical research documenting human efforts to reduce risk from climate change and associated hazards. Coding and synthesizing this literature highlights that the overall extent of adaptation across global regions and sectors is low. Adaptations are largely local and incremental rather than transformative. Behavioural adjustments by individuals and households are more prevalent than any other type of response, largely motivated by drought and precipitation variability. Local governments and civil society are engaging in risk reduction across all sectors and regions, particularly in response to flooding. Urban technological and infrastructural adaptations to flood risk are prevalent in Europe, while shifts in farming practices dominate reporting from Africa and Asia. Despite increasing evidence of adaptation responses, evidence that these responses are reducing risks (observed and projected) remains limited.

The Intergovernmental Panel on Climate Change assessments (IPCC) Special Report on 1.5 °C of global warming is clear. Nearly all pathways that hold global warming well below 2 °C involve carbon removal ( IPCC, 2015 ). In addition, solar geoengineering is being considered as a potential tool to offset warming, especially to limit temperature until negative emissions technologies are sufficiently matured ( MacMartin et al., 2018 ). Despite this, there has been a reluctance to embrace carbon removal and solar geoengineering, partly due to the perception that these technologies represent what is widely termed a “moral hazard”: that geoengineering will prevent people from developing the will to change their personal consumption and push for changes in infrastructure ( Robock et al., 2010 ), erode political will for emissions cuts ( Keith, 2007 ), or otherwise stimulate increased carbon emissions at the social-system level of analysis ( Bunzl, 2008 ). These debates over carbon removal and geoengineering echo earlier ones over climate adaptation. We argue that debates over “moral hazard” in many areas of climate policy are unhelpful and misleading. We also propose an alternative framework for dealing with the tradeoffs that motivate the appeal to “moral hazard,” which we call “risk-response feedback.”

Assessing global progress on human adaptation to climate change is an urgent priority. Although the literature on adaptation to climate change is rapidly expanding, little is known about the actual extent of implementation. We systematically screened >48,000 articles using machine learning methods and a global network of 126 researchers. Our synthesis of the resulting 1,682 articles presents a systematic and comprehensive global stocktake of implemented human adaptation to climate change. Documented adaptations were largely fragmented, local and incremental, with limited evidence of transformational adaptation and negligible evidence of risk reduction outcomes. We identify eight priorities for global adaptation research: assess the effectiveness of adaptation responses, enhance the understanding of limits to adaptation, enable individuals and civil society to adapt, include missing places, scholars and scholarship, understand private sector responses, improve methods for synthesizing different forms of evidence, assess the adaptation at different temperature thresholds, and improve the inclusion of timescale and the dynamics of responses. Determining progress in adaptation to climate change is challenging, yet critical as climate change impacts increase. A stocktake of the scientific literature on implemented adaptation now shows that adaptation is mostly fragmented and incremental, with evidence lacking for its impact on reducing risk.

Future scenarios and pathways of potential development trajectories are powerful tools to assist with decision-making to address many sustainability challenges. Such scenarios play a major role in global environmental assessments (GEAs). Currently, however, scenarios in GEAs are mostly developed at the global level by experts and researchers, and locally imagined, bottom-up scenarios do not play a role in such assessments. In this paper, we argue that addressing future sustainability challenges for achieving more equitable development in GEAs requires a more explicit role for bottom-up inspired futures. To this end, this paper employs an innovative global assessment framework for exploring alternative futures that are grounded in local realities and existing practical actions, and that can be appropriately scaled to the required decision-making level. This framework was applied in the context of the UN’s Global Environment Outlook 6, a major example of a GEA. We developed novel methods for synthesizing insights from a wide range of local practices and perspectives into global futures. We collected information from crowdsourcing platforms, outcomes of participatory workshops in different regions of the world, and an assessment of reported regional outlooks. We analysed these according to a framework also used by an integrated assessment model in the same GEA. We conclude that bottom-up approaches to identify and assess transformative solutions that envision future pathways towards greater sustainability significantly strengthen current GEA scenario-development approaches. They provide decision makers with required actionable information based on tangible synergistic solutions that have been tested on the ground. This work has revealed that there are significant opportunities for the integration of bottom-up knowledge and insights into GEAs, to make such assessments more salient and valuable to decision makers.

Africa has only contributed a small fraction of global greenhouse gas emissions yet faces disproportionate risks from climate change. This imbalance is one of many inequities associated with climat...

Solar geoengineering is often framed as a stopgap measure to decrease the magnitude, impacts, and injustice of climate change. However, the benefits or costs of geoengineering for human health are largely unknown. We project how geoengineering could impact malaria risk by comparing current transmission suitability and populations-at-risk under moderate and high greenhouse gas emissions scenarios (Representative Concentration Pathways 4.5 and 8.5) with and without geoengineering. We show that if geoengineering deployment cools the tropics, it could help protect high elevation populations in eastern Africa from malaria encroachment, but could increase transmission in lowland sub-Saharan Africa and southern Asia. Compared to extreme warming, we find that by 2070, geoengineering would nullify a projected reduction of nearly one billion people at risk of malaria. Our results indicate that geoengineering strategies designed to offset warming are not guaranteed to unilaterally improve health outcomes, and could produce regional trade-offs among Global South countries that are often excluded from geoengineering conversations.

Solar geoengineering is often framed as a stopgap measure to decrease the magnitude, impacts, and injustice of climate change. However, the costs or benefits of geoengineering for human health are largely unknown. We project how geoengineering could impact malaria risk by comparing transmission suitability and populations-at-risk today against moderate and high emissions scenarios (RCP 4.5 and 8.5) with and without geoengineering over the next half-century. We show that if geoengineering deployment cools the tropics, it could help protect high elevation populations in eastern Africa from the encroachment of malaria, but could increase transmission in lowland sub-Saharan Africa and southern Asia. Compared to extreme warming, we also find that by 2070, geoengineering would nullify a projected reduction of nearly one billion people at risk of malaria. Our results indicate that geoengineering strategies designed to offset warming are not guaranteed to unilaterally improve health outcomes, and could produce regional trade-offs among Global South countries that are often excluded from geoengineering conversations.

Climate change is a threat to food security. Wild-harvested food plants (WFPs) are important for the diets of millions of people and contribute to food security, especially in rural and low-income communities, but little is known about climate change risk to these species. Using species distribution models, we examined climate change risk to 1190 WFP species used by 19 native language groups in southern Africa. We project that 40% of species will experience a decrease in range extent within southern Africa by 2060–2080 under a low warming scenario (Representative Concentration Pathway (RCP) 2.6), increasing to 66% under a high warming scenario (RCP 8.5). Decreases in geographic range are projected for >70% of WFP species traditionally used by some language groups. Loss of suitable climatic conditions is projected to decrease WFP species richness most in north-eastern southern Africa – with losses of >200 species – while increases in species richness are projected in the south and east of South Africa. Availability of WFP species for food security during lean times is also projected to change. Specifically, in south-eastern South Africa, local diversity of WFPs is projected to increase, while maize and sorghum yields decrease. However, this potential WFP nutritional safety net may be lost in central parts of the region, where declines in both crop yield and WFPs are projected. By looking beyond conventional crops to the exceptional diversity of WFPs, this research makes a first step towards understanding the linkages between WFPs, traditional knowledge, agriculture, food security, and climate change.

The COVID-19 pandemic will be an unprecedented test of governments’ ability to manage compound risks, as climate hazards disrupt outbreak response around the world. Immediate steps can be taken to minimize climate-attributable loss of life, but climate adaptation also needs a long-term strategy for pandemic preparedness.

At least 10,000 species of mammal virus are estimated to have the potential to spread in human populations, but the vast majority are currently circulating in wildlife, largely undescribed and undetected by disease outbreak surveillance 1–3 . In addition, changing climate and land use are already driving geographic range shifts in wildlife, producing novel species assemblages and opportunities for viral sharing between previously isolated species 4, 5 . In some cases, this will inevitably facilitate spillover into humans 6, 7 —a possible mechanistic link between global environmental change and emerging zoonotic disease 8 . Here, we map potential hotspots of viral sharing, using a phylogeographic model of the mammal-virus network, and projections of potential geographic range shifts for 3,139 mammal species under climate change and land use scenarios for the year 2070. Range-shifting mammal species are predicted to aggregate at high elevations, in biodiversity hotspots, and in areas of high human population density in Asia and Africa, driving the novel cross-species transmission of their viruses an estimated 4,000 times. Counter to expectations, holding warming under 2°C within the century does not reduce new viral sharing, due to greater potential range expansions— highlighting the need to invest in surveillance even in a low-warming future. Most projected viral sharing is driven by diverse hyperreservoirs (rodents and bats) and large-bodied predators (carnivores). Because of their unique dispersal capacity, bats account for the majority of novel viral sharing, and are likely to share viruses along evolutionary pathways that could facilitate future emergence in humans. Our findings highlight the urgent need to pair viral surveillance and discovery efforts with biodiversity surveys tracking species’ range shifts, especially in tropical countries that harbor the most emerging zoonoses.

At least 10,000 virus species have the ability to infect humans but, at present, the vast majority are circulating silently in wild mammals

Livestock comprise the largest mammalian biomass on Earth and contribute to global food security. However, despite numerous case studies reporting heat impacts, the global risk of heat-related stress to livestock from climate change remains unquantified. Here, we conducted a global synthesis of documented heat stress in cattle to identify heat thresholds associated with decreased production and fertility, and increased mortality, and mapped these conditions worldwide for current and future climates. We find that unmitigated climate change will increase the duration of multiple-month heat stress outside the tropics whereas severity will increase most in the tropics and sub-tropics. Our results show that development pathways expanding cattle production into tropical forest regions in South America and Africa will both exacerbate climate change and expose hundreds of millions more cattle to increased heat stress, highlighting the contradiction of pursuing land-use practices that are themselves placed at high risk from resulting future climate hazards.

Solar geoengineering is receiving increased policy attention as a potential tool to offset climate warming. While climate responses to geoengineering have been studied in detail, the potential biodiversity consequences are largely unknown. To avoid extinction, species must either adapt or move to track shifting climates. Here, we assess the effects of the rapid implementation, continuation and sudden termination of geoengineering on climate velocities—the speeds and directions that species would need to move to track changes in climate. Compared to a moderate climate change scenario (RCP4.5), rapid geoengineering implementation reduces temperature velocities towards zero in terrestrial biodiversity hotspots. In contrast, sudden termination increases both ocean and land temperature velocities to unprecedented speeds (global medians >10 km yr−1) that are more than double the temperature velocities for recent and future climate change in global biodiversity hotspots. Furthermore, as climate velocities more than double in speed, rapid climate fragmentation occurs in biomes such as temperate grasslands and forests where temperature and precipitation velocity vectors diverge spatially by >90°. Rapid geoengineering termination would significantly increase the threats to biodiversity from climate change.

Achieving the Sustainable Development Goals requires examining the impacts of health interventions across multiple sectors and identifying regions where health–development–environment conflicts are most likely. Doing this is important for ending the epidemic of malaria by 2030 alongside achieving other SDGs.

Reducing vulnerability is essential for adaptation to climate change. Compared to approaches that examine vulnerability to a specific hazard, our analysis offers an alternative perspective that conceptualizes vulnerability to climate change as a phenomenon that is independent of any specific type of hazard but relevant to multiple hazards. Vulnerability is thus a product of structural inequality and systemic in nature. Based on two established index systems, we perform global analyses of specific phenomena—such as poverty, access to basic infrastructure services and forced migration—that influence and determine vulnerability. Our statistical and spatial analyses reveal an emerging pattern of climate vulnerability within regional clusters and shows that vulnerability is a transboundary issue, crossing political, sectorial and geographical borders and impacting shared resources. The spatial statistical hotspot analysis of vulnerability underscores that hotspots, for example of high vulnerability, state fragility, low biodiversity protection or forced migration, emerge in multi-country clusters. This aspect has often been overlooked, most attention to-date having been given to the positioning of individual countries within vulnerability rankings. In hotspots such as in the Sahel, East and Central Africa, as well as in Southern Asia and Central America, vulnerability is interwoven with high levels of state fragility, making adaptation solutions more complex. The recognition of the regional clusters and the transboundary nature of vulnerability calls for new research and action on how to strengthen transboundary approaches for vulnerability reduction, potentially enhancing prospects for successful adaptation.

Considering the feasibility and effectiveness of adaptation options is essential for guiding responses to climate change that reduce risk. Here, we assessed the feasibility of adaptation options for the African context. Using the Global Adaptation Mapping Initiative, a stocktake of adaptation-related responses to climate change from the peer-reviewed literature in 2013–2020, we found 827 records of adaptation actions in Africa. We categorised and evaluated 24 adaptation options and for each option, six dimensions of feasibility were considered: economic, environmental, social, institutional, technological, and evidence of effectiveness. Over half (51%) of all adaptation actions were reported in the food sector where sustainable water management (SWM) was the most reported option. The fewest actions were reported for cities (5%). The majority of actions (53%) were recorded in just six countries: Ghana, Ethiopia, Kenya, Tanzania, Nigeria and South Africa. Encouragingly, effectiveness was assessed as medium or high for 95% of adaptation options. However, no options had high feasibility on any other dimension. Technological and institutional factors present major barriers to implementation. Crop management, SWM, sustainable agricultural practices, agroforestry, livelihood diversification, ecosystem governance and planning, health governance and planning, infrastructure and built environment, all had moderate feasibility across three or more dimensions. Human migration has low feasibility but high potential for risk reduction. Major knowledge gaps exist for environmental feasibility, for assessing adaptation limits at increasing levels of climate hazard, for economic trade-offs and synergies, and for Central and Northern Africa. Our results highlight sectors where enablers for adaptation can be increased. Future assessments can apply the method established here to extend findings to other national and local levels.

Climate change will almost certainly cause millions of deaths. Climate engineering might prevent this, but benefits — and risks — remain mostly unevaluated. Now is the time to bring planetary health research into climate engineering conversations.

Urbanisation is driving rapid declines in species richness and abundance worldwide, but the general implications for ecosystem function and services remain poorly understood. Here, we integrate global data on bird communities with comprehensive information on traits associated with ecological processes to show that assemblages in highly urbanised environments have substantially different functional composition and 20% less functional diversity on average than surrounding natural habitats. These changes occur without significant decreases in functional dissimilarity between species; instead, they are caused by a decrease in species richness and abundance evenness, leading to declines in functional redundancy. The reconfiguration and decline of native functional diversity in cities are not compensated by the presence of exotic species but are less severe under moderate levels of urbanisation. Thus, urbanisation has substantial negative impacts on functional diversity, potentially resulting in impaired provision of ecosystem services, but these impacts can be reduced by less intensive urbanisation practices.

Animals have diversified into a bewildering variety of morphological forms exploiting a complex configuration of trophic niches. Their morphological diversity is widely used as an index of ecosystem function, but the extent to which animal traits predict trophic niches and associated ecological processes is unclear. Here we use the measurements of nine key morphological traits for99% bird species to show that avian trophic diversity is described by a trait space with four dimensions. The position of species within this space maps with 70-85% accuracy onto major niche axes, including trophic level, dietary resource type and finer-scale variation in foraging behaviour. Phylogenetic analyses reveal that these form-function associations reflect convergence towards predictable trait combinations, indicating that morphological variation is organized into a limited set of dimensions by evolutionary adaptation. Our results establish the minimum dimensionality required for avian functional traits to predict subtle variation in trophic niches and provide a global framework for exploring the origin, function and conservation of bird diversity.

Urbanization presents novel challenges to native species by altering both the biotic and abiotic environments. The rapid pace of declines in species diversity and ecosystem services makes generalizations imperative. Studies have attempted to make generalizations about how species with similar traits respond to urbanization, although the results of such studies are geographically idiosyncratic. Here, we present a comparative study in three US cities: Fresno, California; Tucson, Arizona; and Phoenix, Arizona in an attempt to examine consistency in how urbanization affects native bird assemblages. Using presence-absence data to define regional and urban species pools, we tested for whether the urban avian assemblage is a random subset of the regional avian assemblages on the basis of both traits and phylogeny, and whether or not urbanization causes biotic homogenization among avian assemblages. We found little evidence for non-random trait shifts, with only distributions of diet guild, migratory status, and main habitat showing any significant change, and no evidence for non-random phylogenetic patterns in urban avian assemblages. We did however find some evidence for neutral processes in species’ occupancy of urban habitats. Species in the urban species pools have a higher median reporting frequency than species in the regional species pools in all three cities, although this difference is statistically significant in only one city. Cluster analyses show that levels of biotic homogenization are more severe in spring than in winter. The results presented here indicate that while urban avian assemblage structure may be determined by species’ traits, which may possess phylogenetic signal, simple occurrence in an urban area is likely due to random or neutral processes. The seasonality of homogenization has not to our knowledge been previously reported. We propose that the largely similar results from the three cities in this study result from structural similarities in the matrix habitats, and that the nature of matrix habitat and context of urbanization needs to be considered in future studies in order to resolve existing inconsistencies.

Understanding how pathogens and parasites diversify through time and space is fundamental to predicting emerging infectious diseases. Here, we use biogeographic, coevolutionary and phylogenetic analyses to describe the origin, diversity, and distribution of avian malaria parasites in the most diverse avifauna on Earth. We first performed phylogenetic analyses using the mitochondrial cytochrome b (cyt b) gene to determine relationships among parasite lineages. Then, we estimated divergence times and reconstructed ancestral areas to uncover how landscape evolution has shaped the diversification of Parahaemoproteus and Plasmodium in Amazonia. Finally, we assessed the coevolutionary patterns of diversification in this host-parasite system to determine how coevolution may have influenced the contemporary diversity of avian malaria parasites and their distribution among Amazonian birds. Biogeographic analysis of 324 haemosporidian parasite lineages recovered from 4178 individual birds provided strong evidence that these parasites readily disperse across major Amazonian rivers and this has occurred with increasing frequency over the last five million years. We also recovered many duplication events within areas of endemism in Amazonia. Cophylogenetic analyses of these blood parasites and their avian hosts support a diversification history dominated by host switching. The ability of avian malaria parasites to disperse geographically and shift among avian hosts has played a major role in their radiation and has shaped the current distribution and diversity of these parasites across Amazonia.

Slow progress reducing greenhouse gas emissions has increased attention on whether solar radiation management (SRM) geoengineering is a feasible and affordable tool to cool Earth, buying time for additional adaptation and mitigation efforts. Climate responses to several idealized SRM simulations have been studied in detail. In contrast, evaluating the plausibility of different SRM scenarios remains difficult and more collaboration between natural and social scientists is required. Moreover, the environmental and social impacts remain essentially unknown. We review evidence on impacts across stratospheric aerosol injection and marine cloud brightening technologies and scenarios. Rapid SRM termination, resulting in rapid climate change, would significantly increase threats to global biodiversity and ecosystems from climate change, especially in the tropics. In contrast, more measured use of SRM could reduce some climate risks for biodiversity but further research is needed. Agricultural impacts from geoengineering are predicted to be complicated. In general, cooling from SRM would benefit most crops but precipitation reductions could have negative impacts on rice and groundnuts in Asia. SRM strategies may also have impacts on human health from aerosol deposition at the surface.

SUMMARYParasites of the generaPlasmodiumandHaemoproteus(Apicomplexa: Haemosporida) are a diverse group of pathogens that infect birds nearly worldwide. Despite their ubiquity, the ecological and evolutionary factors that shape the diversity and distribution of these protozoan parasites among avian communities and geographic regions are poorly understood. Based on a survey throughout the Neotropics of the haemosporidian parasites infecting manakins (Pipridae), a family of Passerine birds endemic to this region, we asked whether host relatedness, ecological similarity and geographic proximity structure parasite turnover between manakin species and local manakin assemblages. We used molecular methods to screen 1343 individuals of 30 manakin species for the presence of parasites. We found no significant correlations between manakin parasite lineage turnover and both manakin species turnover and geographic distance. Climate differences, species turnover in the larger bird community and parasite lineage turnover in non-manakin hosts did not correlate with manakin parasite lineage turnover. We also found no evidence that manakin parasite lineage turnover among host species correlates with range overlap and genetic divergence among hosts. Our analyses indicate that host switching (turnover among host species) and dispersal (turnover among locations) of haemosporidian parasites in manakins are not constrained at this scale.