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In response to biodiversity declines worldwide, over 190 nations committed to protect 30% of their lands and waters by 2030 (hereafter, 30×30). Systematic conservation planning and return on investment analysis can be helpful tools for determining where protection efforts could deliver the most efficient and effective reserve design, and supporting decision‐making when trade‐offs among objectives are required. Here, we propose a framework for efficient “30×30” implementation and apply it to the state of California (USA). Because conservation of a region's full suite of biodiversity is the primary objective of the global initiative, we prioritized representation in our analysis. We used Zonation to identify networks that close the gap in representation of major habitat types in California's protected area network and that also conserve the places important for biodiversity or climate change mitigation. We identified networks that are efficient relative to metrics likely to be important in implementation including land acquisition cost, number of transactions, and conservation benefit per hectare, and we illustrate not only trade‐offs associated with these metrics but also differences in the co‐benefits achieved. Five of the eight major habitat types in California are not currently protected at a 30% level statewide, and if representation was achieved solely through private land acquisition, targets could be met for as little as $5.84 billion, with as few as 364 transactions, or with 2.18 million additional conserved hectares. Implementation of 30×30 will likely require more flexibility than a single network design. A “no regrets” action would be to protect properties that were prioritized across all networks and additional implementation should include properties with characteristics of any of the individual networks. Our analytical framework and implementation guidance can be applied to other geographies and jurisdictions to increase the likelihood of both meeting 30×30 targets and delivering the conservation benefits they aim to secure. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Genebanks contribute to global food security, directly influencing societal well‐being, by providing access to seed or genetic material that is more resilient to pests, diseases, and environmental stresses. The ability to develop crops adapted to changing environmental conditions and with high nutritional value means societies can better cope with the adverse effects of climate change, safeguarding food production and rural livelihoods. Enhancing sustainable crop traits, such as improved water‐use efficiency and nutrient utilization, supports the transition toward more sustainable agricultural practices. New technologically advanced phenotyping tools are required to optimally realize the potential of these genetic resources, to identify plant genetic resources that will best enable us to address current global challenges.Plant genebanks have a crucial role as specialized repositories, preserving diverse plant genetic resources and providing essential access to researchers, breeders, and farmers for developing resilient crops. With over 7 million global accessions, these genebanks significantly contribute to global food security, climate change mitigation, and sustainable agriculture. This opinion paper, inspired by an international workshop in 2022 in Wageningen (Netherlands), focuses on the transformative impact of phenomics technology within genebanks, offering a view on its potential applications and implications for preserving and utilizing plant genetic resources. Discussions from the 2022 workshop organized by the International Plant Phenotyping Network are integrated, emphasizing the potential of phenomics for global collaboration without requiring major policy developments. The workshop prioritized traits like disease resistance and drought tolerance, highlighting roots as a critical organ for phenotyping. Participants expressed a keen interest in global collaboration, emphasizing the need for partnerships between genebanks and advanced phenotyping facilities. The workshop's outcomes underscore the transformative impact of phenomics on genebanks, promoting innovation, collaboration, and sustainable agricultural practices. These results will guide future pilot studies, marking a significant step toward integrating phenomics into genebank practices and ensuring the continued prosperity of plant genetic heritage. [ABSTRACT FROM AUTHOR]

Climate change poses a massive and growing threat to wildlife. Calls are growing for coordinated and collaborative responses to conserve species threatened by climate change, but how this works in practice remains largely unexplored. Focusing on seabirds in North‐West Europe, we carried out 32 semi‐structured stakeholder interviews to (1) explore existing conservation work linked to climate change, (2) identify barriers to work on climate change among conservation actors, and (3) identify key conservation actors and characterize their interactions. Interviewees identified a range of research, policy, and practical conservation work for seabirds related—directly or indirectly—to climate change. They highlighted the importance of general conservation work to facilitate seabird adaptation to climate change, and global mitigation of climate change (e.g., through decarbonization and ecosystem restoration). Interviewees identified several barriers to conservation work explicitly addressing climate change, pertaining to information, leadership, resources, and values/beliefs. We discovered that seabird conservation networks are generally well‐established and harmonious, but not tension‐free. There are also some misunderstandings over actor responsibilities that could lead to bystander effects. We present suggestions to increase the effectiveness and efficiency of seabird conservation in response to climate change. [ABSTRACT FROM AUTHOR]

Biofuels are essential to ensure the energy transition and mitigating of climate change. However, understanding the impact of land use change (LUC) and management practices on soil organic carbon (SOC) stocks is fundamental to ensuring well‐founded policymaking and assessing the sector's carbon footprint. Here, we conducted a meta‐analysis (511 pairwise observations) to obtain Brazil's SOC stock change factors (SOCscf) for LUC and management practices in sugarcane fields. Our results showed that converting native vegetation to sugarcane reduced the SOC stock in all assessed periods. The conversion from annual crops to sugarcane showed a reduction in SOC stock in the first 10 years but with a recovery over time. The conversion of pasture to sugarcane reduced the SOC stock only in the 10–20‐year period and had a neutral effect in other periods evaluated. However, our dataset showed high variability in SOCscf, with many observations indicating an increase in SOC stock, which is related to degraded pastures. We observed that the SOC accumulation rate for each ton of sugarcane straw was affected by the interaction between soil texture and precipitation. Regarding straw management, a low removal rate (< 34%) did not affect the SOC stock, while moderate (34%–66%) and high (> 66%) removal resulted in losses of 5.0% (SOCscf 0.950) and 9.9% (SOCscf 0.901), respectively. Our results also showed that reduced tillage and vinasse application increased SOC stocks by 24.0% (SOCscf 1.24) and 10.0% (SOCscf 1.10) respectively, proving to be good strategies to support C sequestration in sugarcane fields. Finally, we highlight that our results can contribute to the improvement of public policies and also be used in future life cycle assessment (LCA) and modeling studies, as they provide robust data to establishing regional SOCscf induced by LUC and management practices, enhancing the reliability of the C footprint assessment of biofuel production. [ABSTRACT FROM AUTHOR]

Understanding mechanisms stabilizing ecosystem functions, such as primary production, is crucial for forecasting global environmental responses. While biological diversity is expected to enhance stability through compensatory reactions to environmental changes, empirical evidence is lacking, especially in old‐growth forests vital for biodiversity conservation and climate change mitigation. Moreover, whether increased niche complementarity and stronger intraspecific than interspecific competition are key mechanisms promoting compensatory dynamics and stabilizing ecosystem functions in diverse forests remains unexplored. This study investigates productivity and stability in temperate old‐growth forests over 20 years at community and individual levels. Analysing 4380 trees in a 4‐ha plot in northern Japan with over 35 tree species, structural equation models evaluated the effects of biodiversity and average asynchrony in species fluctuations (compensatory dynamics) on productivity stability across 100 m2 grid quadrats. Functional traits and taxonomic diversity represented species complementarity and the insurance effect. Temporal growth correlations between conspecific and heterospecific neighbours and neighbourhood effects on growth performance indicated intra‐ and interspecific interactions at the individual level. Communities with greater stability exhibited higher diversity and asynchronous species fluctuations, suggesting that compensatory dynamics buffer community productivity against environmental variability. The inverse relationship between tree size variation and stability indicates that communities with less pronounced size and abundance hierarchies have more efficient compensatory mechanisms, ensuring stable forest functioning. The absence of negative temporal correlations in biomass production among heterospecific neighbours suggests the limited significance of interspecific competition in compensatory dynamics. Conversely, positive correlations among conspecific neighbours and their suppressed growth in dense conspecific patches highlight the importance of conspecific negative density‐dependent mechanisms in sustaining tree species diversity and ensuring stable productivity. Synthesis: The study underscores the critical role of tree species richness in stabilizing ecosystem functioning via asynchronous growth in one of the world's most diverse temperate forests. Stronger intraspecific than interspecific competition helps prevent single‐species dominance, maintaining diversity and productivity stability. Despite occasional destabilization from size‐asymmetric interspecific competition, species‐trait complementarity enhances stability by promoting overall biomass production. This study highlights the importance of overall diversity for the stability of forest productivity, with implications for nature conservation and ecosystem functionality. [ABSTRACT FROM AUTHOR]

Societal Impact Statement Summary Free‐air CO2 enrichment (FACE) experiments provide essential data on forest responses to increasing atmospheric CO2 for evaluations of climate change impacts on humanity. Understanding and reducing the uncertainty in the experimental results is critical to ensure scientific and public confidence in the models and policy initiatives that derive therefrom. One source of uncertainty is the estimation of tree biomass using mathematical relationships between biomass and easily obtained and non‐destructive measurements (allometry). We evaluated the robustness of the allometric relationships established at the beginning of a FACE experiment and discuss the challenges and opportunities for the new generation of FACE experiments. Long‐term field experiments to elucidate forest responses to rising atmospheric CO2 concentration require allometric equations to estimate tree biomass from non‐destructive measurements of tree size. We analyzed whether the allometric equations established at the beginning of a free‐air CO2 enrichment (FACE) experiment in a Liquidambar styraciflua plantation were still valid at the end of the 12 year experiment. Aboveground woody biomass was initially predicted by an equation that included bole diameter, taper, and height, assuming that including taper and height as predictors would accommodate changes in tree structure that might occur over time and in response to elevated CO2. At the conclusion of the FACE experiment, we harvested 23 trees, measured dimensions and dry mass of boles and branches, and extracted and measured the woody root mass of 10 trees. Although 10 of the harvested trees were larger than the trees used to establish the allometric relationship, measured aboveground woody biomass was well predicted by the original allometry. The initial linear equation between bole basal area and woody root biomass underestimated final root biomass by 28%, but root biomass was just 21% of total wood mass, and errors in aboveground and belowground estimates were offsetting. The allometry established at the beginning of the experiment provided valid predictions of tree biomass throughout the experiment. New allometric approaches using terrestrial laser scanning should reduce an important source of uncertainty in decade‐long forest experiments and in assessments of centuries‐long forest biomass accretion used in evaluating carbon offsets and climate mitigation. [ABSTRACT FROM AUTHOR]

Surf breaks are increasingly recognized as socio‐environmental phenomena that provide opportunities for biodiversity conservation and sustained benefits for local communities. Here, we examine an additional benefit from improved conservation of the ecosystems that host and surround surf breaks—their coincidence with carbon dense coastal ecosystems. Using global spatial datasets of irrecoverable carbon (defined as carbon stocks that, if lost today, could not be recovered within 30 years' time), surf break locations, ecosystem types, protected areas, and Key Biodiversity Areas, we identified 88.3 million tonnes of irrecoverable carbon held in surf ecosystems. Of this total, 17.2 million tonnes are found in Key Biodiversity Areas without formal measures of protection. These results highlight surf conservation as a potential avenue to simultaneously mitigate climate change, protect biodiversity, and promote sustainable development in coastal communities. [ABSTRACT FROM AUTHOR]

Executive Order No. 14008 mandated that U.S. federal agencies and departments develop Climate Change Adaptation Plans to enhance the nation's resilience to climate change. Invasive species are documented to reduce the effectiveness of climate adaptation and mitigation actions. In spite of this, only eight of the 26 federal plans directly reference invasive species, and just four meaningfully consider the reciprocal impact of invasive species on climate adaptation efforts. To ensure that climate adaptation planning and processes are effective with associated benefits for biodiversity conservation, a gap analysis of the Climate Change Adaptation Plans was conducted. Five key recommendations were developed that would transform how invasive species are considered within them. Examples of how invasive species have been included in some of the plans are provided, with suggestions for agencies that did not include invasive species on how they might do so, to illustrate that dedicated efforts in prevention, detection, and management of invasive species can safeguard carbon sequestration, protect communities and infrastructure, and minimize economic and biodiversity losses. Although developed based on U.S. federal plans, these recommendations can be used by state and local, as well as international, jurisdictions tasked with implementing climate‐adaptive policies to build resilience across multiple sectors. [ABSTRACT FROM AUTHOR]

Mangroves are implemented as nature‐based solutions (NbS) for coastal protection, climate change mitigation (carbon sequestration) and other services. They play a core role in providing benefits for biodiversity, livelihoods and human well‐being. Ecological research has informed the use of mangroves as NbS, but failure of NbS projects has often been due to misconceptions about mangrove ecology and the limited use of the wide range of ecological knowledge available. Enhanced knowledge of the spatial and temporal variation in ecological processes, and differentiation among mangrove tree species and assemblages (including fauna and microbial communities) in the provision of ecosystem functions and services, will support successful use of mangroves as NbS. Knowledge of mangrove responses to the interacting pressures of climate change and human uses of the coastal zone will support resilient NbS projects. Synthesis. The success of mangroves as NbS can be improved with increased incorporation of knowledge of the ecology of mangrove plants, animals and microbes and by sharing and co‐producing knowledge within mangrove societies. [ABSTRACT FROM AUTHOR]

Despite the importance of protecting forests and woodlands to achieve global climate and biodiversity goals, logging impacts persist worldwide. Forestry advocates often downplay these impacts but rarely consider the cumulative threat deforestation and degradation has had, and continues to have, on biodiversity. Using New South Wales (Australia) as a case study, we quantify the extent of deforestation and degradation from 1788 (pre‐European colonization) to 2021. We used historical loss as a baseline to evaluate recent logging (2000–2022) and the condition of the remaining native forest and woodland. Condition was quantified by measuring the similarity of a current ecosystem to a historical reference state with high ecological integrity. Using these data, we measured the impacts on 269 threatened terrestrial species. We show that possibly over half (29 million ha) of pre‐1788 native forest and woodland vegetation in NSW has been lost. Of the remaining 25 million ha, 9 million ha is estimated to be degraded. We found recent logging potentially impacted 150 species that had already been affected by this historical deforestation and degradation, but the impacts varied across species. Forty‐three species that were identified as impacted by historical deforestation and degradation and continue to be impacted by logging, now have ≤50% of their pre‐1788 extent remaining that is intact and nine species now have ≤30%. Our research contextualizes the impact of current logging against historical deforestation and highlights deficiencies in environmental assessments that ignore historical baselines. Future land management must consider both the extent and condition of remaining habitat based on pre‐1788 extents. [ABSTRACT FROM AUTHOR]

This perspective article delves into the transformative potential of alkali‐activated materials, acid‐activated materials, and geopolymers in mitigating climate change and market challenges. To harness the benefits of these materials, a comprehensive strategy is proposed. This strategy aims to integrate these materials into existing construction regulations, facilitate certification, and promote market access. Emphasizing research and innovation, the article advocates for, increased funding to refine the chemistry and production of these materials, prioritizing low‐cost alternatives and local waste materials. Collaboration between academia and industry is encouraged to expedite technological advances and broaden applications. This article also underscores the need to develop economic and business models emphasizing the long‐term benefits of these materials, including lower life‐cycle costs and reduced environmental impact. Incentivizing adoption through financial mechanisms like tax credits and subsidies is suggested. The strategy also includes scaling up production technology, fostering industrial collaboration for commercial viability, and developing global supply chains. Educational programs for professionals and regulators are recommended to enhance awareness and adoption. Additionally, comprehensive life‐cycle assessments are proposed to demonstrate environmental benefits. The strategy culminates in expanding the applications of these materials beyond construction, fostering international collaboration for knowledge sharing, and thus positioning these materials as essential for sustainable construction and climate change mitigation. [ABSTRACT FROM AUTHOR]

Terrestrial, aquatic, and marine ecosystems regulate climate at local to global scales through exchanges of energy and matter with the atmosphere and assist with climate change mitigation through nature‐based climate solutions. Climate science is no longer a study of the physics of the atmosphere and oceans, but also the ecology of the biosphere. This is the promise of Earth system science: to transcend academic disciplines to enable study of the interacting physics, chemistry, and biology of the planet. However, long‐standing tension in protecting, restoring, and managing forest ecosystems to purposely improve climate evidences the difficulties of interdisciplinary science. For four centuries, forest management for climate betterment was argued, legislated, and ultimately dismissed, when nineteenth century atmospheric scientists narrowly defined climate science to the exclusion of ecology. Today's Earth system science, with its roots in global models of climate, unfolds in similar ways to the past. With Earth system models, geoscientists are again defining the ecology of the Earth system. Here we reframe Earth system science so that the biosphere and its ecology are equally integrated with the fluid Earth to enable Earth system prediction for planetary stewardship. Central to this is the need to overcome an intellectual heritage to the models that elevates geoscience and marginalizes ecology and local land knowledge. The call for kilometer‐scale atmospheric and ocean models, without concomitant scientific and computational investment in the land and biosphere, perpetuates the geophysical view of Earth and will not fully provide the comprehensive actionable information needed for a changing climate. Plain Language Summary: Terrestrial ecosystems provide a natural solution to planetary warming by storing carbon, dissipating surface heating through evapotranspiration, and other processes. That forests, in particular, influence climate is a centuries‐old premise, but its potential for planetary stewardship has not been realized. In an acrimonious controversy spanning several centuries, managing forests to purposely change climate was advocated, legislated, and resoundingly dismissed as unscientific. Similar intellectual bias is evident in today's Earth system science and the associated Earth system models, which are the state‐of‐the‐art models used to inform climate policy. The popular characterization of Earth system science lauds its interdisciplinary melding of physics, chemistry, and biology, but the models emphasize the physics and fluid dynamics of the atmosphere and oceans and present a limited perspective of terrestrial ecosystems in the Earth system. Ecologists studying the living world increasingly have a voice in Earth system science as we move beyond the physical basis for climate change to Earth system prediction for planetary stewardship. As we once again look to forests to solve a climate problem, we must surmount the disciplinary narrowness that failed to answer the forest‐climate question in the past and that continues to limit the interdisciplinary potential of Earth system science. Key Points: Nature‐based climate solutions have been advocated for centuries, but have been distorted by academic bias and colonialist prejudiceEarth system science, while recognizing the climate services of the biosphere, has a geophysical bias in interdisciplinary collaborationTo realize the potential for planetary stewardship, Earth system models must embrace the living world equally with the fluid world [ABSTRACT FROM AUTHOR]

We present a framework for strategic dam planning under uncertainty, which includes GHG emissions mitigation as a novel objective. We focus on the Mekong River Basin, a fast‐developing region heavily relying on river‐derived ecosystem services. We employ a multi‐objective evolutionary algorithm to identify strategic dam portfolios for different hydropower expansion targets, using process‐related and statistical models to derive indicators of sediment supply disruption and GHG emissions. We introduce a robust optimization approach that explores variations in optimal portfolio compositions for more than 5,000 state‐of‐the‐world configurations, regarding sediment origins and trapping and GHG emissions. Thus, we can rank dam projects' attractiveness based on their frequency of inclusion in optimal portfolios and explore how uncertainty affects these rankings. Our results suggest that developing dams in the upper Mekong would be a more robust option for near‐term development than, for example, the lower Mekong and its tributaries, for both environmental and energy objectives. Our work presents a novel approach to better understand the basin‐scale cumulative impacts of dam development in high‐uncertainty, data‐scarce contexts like the Mekong Basin. Plain Language Summary: Hydropower is considered an important energy source to meet many climate mitigation targets. Its negative impacts are however often underestimated, including the emission of greenhouse gases (GHG) from reservoirs. This study introduces a framework for planning dams strategically in the Mekong River Basin, a region heavily dependent on river‐related services. The framework considers uncertainties and incorporates greenhouse gas emissions mitigation and sediment transport disruption as new objectives. Using a multi‐objective evolutionary algorithm, the research identifies optimal dam portfolios for different hydropower expansion goals. To consider uncertainties in the results, the analysis employs a robust optimization approach to assess over 5,000 state‐of‐the‐world configurations. Results indicate that developing dams in the upper Mekong is a more robust option for both environmental and energy goals in the near term. These conclusions showcase the approach's usefulness in understanding dams' cumulative impacts in data‐scarce and uncertain contexts like the Mekong Basin. Key Points: We identify optimal dam portfolios which balance hydropower expansion, sediment supply disruption, and GHG emissions in the MekongWe extracted optimal portfolios under multiple state‐of‐the‐world configurations, to extract robust indicators of project attractivenessResults suggest that near‐term dam development should focus more on the upper Mekong, compared to the lower Mekong and its tributaries [ABSTRACT FROM AUTHOR]

In response to the climate goal of achieving carbon neutrality by 2050, efficient electrochemical energy conversion devices are garnering increasing attention. However, the enhancement of electrochemical performance using noble metal electrocatalysts, along with cost reduction and electrode fabrication, remain significant challenges. Noble metal hybrid nanostructures, possessing multiple surface functionalities, lead to outstanding electrocatalytic performances and low‐cost potential. Strain effects can bolster the bonding strength between the noble metal layers and the substrate or core layers, while simultaneously affecting electrocatalytic performance through tuning the binding strength between catalytically active sites and reactants, including intermediates. This review encapsulates the research efforts directed towards improving the performance of noble metal electrocatalysts and provides an overview of the latest advancements in controlling the surface state of noble metals by incorporating a secondary component. We discuss systematic approaches to adjusting surface strain effects on noble metals, characterization techniques, and application case studies, while extracting key design indicators for readers to consider from a macroscopic perspective. Further, we outline the challenges encountered and current solutions when advancing noble metal catalysts from theoretical mechanisms to practical use. Finally, the perspectives on the future research of noble metal surface layer control techniques were also provided. [ABSTRACT FROM AUTHOR]

Accurate subsurface soil moisture (SM) estimation is critical for vegetation growth, drought monitoring, and climate change mitigation, yet remains a significant challenge. Previous data assimilation (DA) approaches are limited to only surface SM assimilation. In this study, we utilized the proxy subsurface SM estimated via the exponential filter method (ExpF) as another assimilation variable in our 2‐dimensional DA. Meanwhile, the dual updating DA scheme was implemented to simultaneously update model parameters and states. The two DA pathways were incorporated into the proposed framework (DA_1E_D), which enhanced the subsurface SM accuracy, with the effects of 2‐dimensional assimilation being more significant. Under 2‐dimensional DA, the information transfer between layers was more accurately characterized, leading to overall improvements with unbiased root‐mean‐square error (ubRMSE) reductions of 0.015 and 0.005 m3 · m−3, and Kling–Gupta efficiency (KGE) increases of 0.248 and 0.067 for surface and subsurface SM, respectively, across five SM networks. The soil thickness (d2) and hydraulic conductivity exponent (expt2) are the most influential parameters affecting subsurface SM dynamics through model propagation. DA_1E_D also outperformed ExpF in subsurface SM accuracy, particularly in SM networks with weak surface‐subsurface correlation, achieving an average ubRMSE reduction of 0.003 m3 · m−3 and an average KGE increase of 0.202. It was also applied to Soil Moisture Active Passive data at regional scale, demonstrating significant improvements. The model surface‐subsurface SM coupling was adjusted toward the actual coupling after subsurface assimilation and dual updating. This study may provide new insights into the diagnosis and refinements of the model representation of surface‐subsurface processes. Plain Language Summary: Soil moisture (SM) is a key variable in the fields of hydrology, ecology, and agriculture, and in characterizing Earth's climate. Particularly, accurate subsurface SM estimation remains challenging for the Earth science community. Here, we used the empirical subsurface SM estimates derived from an exponential filter method (ExpF) as another assimilation variable, in combination with the data assimilation (DA) technique which updates model states and parameters simultaneously, to constrain the model estimates. We found these two pathways lead to significant improvements in subsurface SM estimation. The accuracy of subsurface SM was improved with biases (ubRMSE) significantly reduced by 0.005 m3 · m−3 on average over the modeling grid cells, due to the assimilation of empirical subsurface SM. The effects of parameter updating were relatively smaller but also positive. The proposed DA framework demonstrated superior accuracy to ExpF, with an average ubRMSE reduction of 0.003 m3 · m−3 and an average KGE increase of 0.202. This framework was also applicable to regional scale using satellite products. Moreover, both pathways proved effective in adjusting the physical surface‐subsurface correlation in the land surface model toward actual coupling. Our analysis has important implications for future studies on estimating subsurface SM using land surface models at larger spatiotemporal scales. Key Points: A 2‐dimensional data assimilation (DA) framework which accounted for a dual state‐parameter updating scheme was proposedThe accuracy of subsurface soil moisture (SM) was improved by assimilating empirical subsurface estimates and dual updatingThe proposed DA framework can also be applied to Soil Moisture Active Passive data to improve subsurface SM estimation at regional scale [ABSTRACT FROM AUTHOR]

The world is facing grand challenges in energy security, environmental pollution, and sustainable use (and re‐use) of resources. Electrochemical processes, incorporating electrosynthesis, electrochemical catalysis, and electrochemical energy storage devices, provide pathways to address these challenges via green chemistry. However, the applicability of electrochemical processes for these systems is limited by the required energy input, the "electrons" in electrochemistry. Electrocatalysis as a subset of electrochemistry is set to underpin many of the United Nations Sustainable Development Goals, including "Affordable and Clean Energy" through the production of future fuels and abatement of carbon emissions; "Responsible Consumption and Production" through recycling and degradation of waste; and "Climate Action" through CO2 (and other greenhouse gas) remediation. The rise of green photovoltaic power has lowered the carbon cost of these electrons, making electrocatalysis an even more viable, green(er), chemical conversion pathway. This perspective highlights the need for comprehensive understanding of catalyst structure via in situ and operando analysis to complement device design considerations. The challenges faced by the field of electrocatalysis in data reporting, elimination of electrochemical artifacts, catalyst stability, and scaling to industrial relevance, along with opportunities, emerging tools, are discussed with a view to achieve the maximum 'potential' of electrocatalysis. [ABSTRACT FROM AUTHOR]

The incidence of vibriosis is rising globally with evidence of climate variability influencing environmental processes that support growth of pathogenic Vibrio spp. The waterborne pathogen, Vibrio vulnificus can invade wounds and has one of the highest case fatality rates in humans. The bacterium cannot be eradicated from the aquatic environment, hence climate driven environmental conditions enhancing growth and dissemination of V. vulnificus need to be understood to provide preemptive assessment of its presence and distribution in aquatic systems. To achieve this objective, satellite remote sensing was employed to quantify the association of sea surface temperature (SST) and chlorophyll‐a (chl‐a) in locations with reported V. vulnificus infections. Monthly analysis was done in two populated regions of the Gulf of Mexico—Tampa Bay, Florida, and Galveston Bay, Texas. Results indicate warm water, characterized by a 2‐month lag in SST, high concentration of phytoplankton, proxied for zooplankton using 1 month lagged chl‐a values, was statistically linked to higher odds of V. vulnificus infection in the human population. Identification of climate and ecological processes thresholds is concluded to be useful for development of an heuristic prediction system designed to determine risk of infection for coastal populations. Plain Language Summary: Our study focused on Vibrio spp., a group of bacteria in warm, slightly salty water. One of these, Vibrio vulnificus, is especially dangerous and can cause severe illness with a high risk of death. The spread of this pathogen in humans is becoming more of a concern due to climate change. We aimed to understand what environmental conditions influence occurrence of the disease caused by this bacterium. The main factor linked to the rise of V. vulnificus is sea surface temperature (SST). However, other factors like chlorophyll also play a role. We used satellite data to monitor SST and chlorophyll levels and statistically associated this data with the number of people getting sick from V. vulnificus. Our findings indicate a pattern: when 2 months prior SST and 1‐month prior chlorophyll levels are higher than their monthly average, the chance of V. vulnificus infections is higher. By using this pattern, we aim to predict better when and where infections might happen, helping identify at‐risk areas and potentially stop outbreaks before they occur. Key Points: Likelihood of Vibrio vulnificus infections is influenced by elevated Sea Surface Temperature and chlorophyll of previous monthsSea Surface Temperature, chlorophyll, and V. vulnificus cases occurrence showed increasing trends during the study periodStatistically significant difference was observed between overall chlorophyll levels and the levels recorded during increased cases of V. vulnificus [ABSTRACT FROM AUTHOR]

Forest restoration is critical for meeting global objectives related to climate change mitigation, biodiversity conservation and sustainable livelihoods.Recently, new technologies such as unmanned aerial vehicles (hereafter drones) have been promoted to support activities across the planning, implementation, monitoring and maintenance stages of forest restoration. Yet, there is little empirical data on how the development and application of drones are perceived by restoration managers and stakeholders and how drones intersect with existing forest social–ecological systems (SESs).Here, we investigate how drone tree planting initiatives in Australia can support ecosystem restoration. Through interviews and focus groups with key actors, we examine the opportunities and challenges that have been experienced or are foreseen with drone use.Opportunities included the ability of drones to access degraded sites that are difficult or unsafe to access on foot, for example, following bushfires, floods or landslides. They were also perceived to ease the labour shortage of bush regenerators in Australia. Drones were considered particularly useful when operating at scales of around 20–100 ha.Challenges included restrictive flying regulations that prohibit use of artificial intelligence to plot courses through complex terrain, their unproven ability to control or eradicate weeds and the uncertain supply, germination and survival rates of seeds—upon which drone‐based restoration relies. Drone use may also reduce the emotional, spiritual and cultural connections of people to the land, as compared to hand‐planting seeds or seedlings.We conclude by conceptualising how drone‐assisted restoration can be embedded within a forest SESs management framework. Ultimately, we argue that drones offer a 'boutique' restoration approach that supports, rather than replaces, traditional forest restoration techniques. Read the free Plain Language Summary for this article on the Journal blog. Read the free Plain Language Summary for this article on the Journal blog. [ABSTRACT FROM AUTHOR]

Subsurface gas storage is crucial for achieving a sustainable energy future, as it helps to reduce CO2 emissions and facilitates the provision of renewable energy sources. The confinement effect of the nanopores in caprock induces distinctive thermophysical properties and fluid dynamics. In this paper, we present a multi‐scale study to characterize the subsurface transport of CO2, CH4, and H2. A nanoscale‐extended volume‐translated Cubic‐Plus‐Association equation of state was developed and incorporated in a field‐scale numerical simulation, based on a full reservoir‐caprock suite model. Results suggest that in the transition from nanoscale to bulk‐scale, gas solubility in water decreases while phase density and interfacial tension increase. For the first time, a power law relationship was identified between the capillary pressure within nanopores and the pore size. Controlled by buoyancy, viscous force and capillary pressure, gases transport vertically and horizontally in reservoir and caprock. H2 has the maximum potential to move upward and the lowest areal sweep efficiency; in short term, CH4 is more prone to upward migration compared to CO2, while in long term, CH4 and CO2 perform comparably. Thicker caprock and larger caprock pore size generally bring greater upward inclination. Gases penetrate the caprock when CH4 is stored with a caprock thickness smaller than 28 m or H2 is stored with a caprock pore size of 2–10 nm or larger than 100 nm. This study sheds light on the fluid properties and dynamics in nanoconfined environment and is expected to contribute to the safe implementation of gigatonne scale subsurface gas storage. Plain Language Summary: Aiming at the ambitious targets of net‐zero emission and global energy transition, effective technologies need to be developed and deployed with huge efforts. Subsurface gas storage is expected to play a critical role in reducing CO2 emission and providing large‐scale renewable energy. However, unforeseen gas leakage can cause potential environmental risks and energy efficiency concerns. Despite its importance, the mechanisms governing gas transport and distribution within caprocks, particularly under nanoconfinement conditions, are poorly understood. From nano‐scale and bulk‐scale thermodynamic properties predictions to field‐scale numerical simulations, this work carried out a comprehensive multi‐scale analysis to evaluate the storage security of CO2, CH4, and H2. Relationships between VLE, phase density, interfacial tension, capillary pressure and pore size, temperature, pressure and wettability were discussed, offering novel perspectives on the mechanisms governing gas leakage. Furthermore, loss potentials of different gases were compared and evaluated and the impacts of caprock thickness and pore size were examined, providing valuable insights for screening eligible storage sites. Overall, this work contributes to the development of secure and reliable gas storage techniques, supporting the goals of climate change mitigation and facilitating the transition to a net‐zero energy future. Key Points: A multi‐scale analysis is carried out to assess the loss potential of CO2, CH4, and H2 during subsurface storageMigration and distribution characteristics of gases in the caprock are investigatedShort‐term and long‐term gas storage security are analyzed and compared [ABSTRACT FROM AUTHOR]

The climate commitment to achieving carbon neutrality before 2060 in China has been announced recently. In the context of pursuing carbon neutrality, sharing similar sources as greenhouse gases, aerosol particle and precursor emissions are projected to substantially decrease in China, which can potentially have a great impact on climate. Here, we investigate the effects of future aerosol reductions, because of achieving carbon neutrality, on solar and wind energy in China by using an earth system model. We show that significant reductions in aerosol emissions, particularly in eastern China, lead to increases in the surface downwelling shortwave radiation, surface air temperature and wind speed, which can further enhance the potential of solar and wind energy production. The findings underline that the pursuit of carbon neutrality can yield co‐benefits of not only mitigating climate change and air pollution but also fortifying the stability of renewable energy sources. Plain Language Summary: In response to China's commitment to achieve carbon neutrality by 2060, our study examines the potential impact of reducing aerosol emissions and greenhouse gases on solar and wind energy generation. Employing an earth system model, we observe significant reductions in aerosols, particularly in eastern China, resulting in increases in surface downwelling shortwave radiation, surface air temperature, and wind speed. These changes have promising implications for enhancing solar and wind energy production. Our research underscores the interconnected benefits of pursuing carbon neutrality, encompassing climate change mitigation, air quality improvement, and the enhancement of renewable energy reliability. Key Points: The effects of future aerosol reductions in China due to achieving carbon neutrality on solar and wind energy are investigatedAerosol emission reductions, especially in eastern China, increase surface downwelling shortwave radiation, temperature and wind speedClimate changes resulting from emission reductions under carbon neutrality enhance the potential of solar and wind energy [ABSTRACT FROM AUTHOR]

The EU Biodiversity Strategy 2030 aims to better protect natural ecosystems with high biodiversity and climate change mitigation potential. To achieve this goal, it is crucial to identify forests worth protecting, such as those characterized by long continuity and old age. Here, we propose a robust approach that combines historical maps from the mid‐19th century with remote sensing data to identify areas that have been forested for over 150 years, aiming to reduce the need for detailed and time‐consuming field investigations in potential conservation areas. We tested this approach in a 20,000 km2 region in the Polish Carpathians, an area likely containing many unprotected forests of high conservation value, where historical maps from the mid‐19th century are representative of much of Central Europe. Our results showed that an area of approximately 4200 km2 has been continuously forested since at least the mid‐19th century. Currently, 50% of these forests are outside protected areas, representing an important conservation opportunity. More generally, our approach can support the identification of valuable forests worth protecting before they are lost and provide useful insights for policymakers and stakeholders in the ongoing debate on the challenges of improving forest conservation in the Carpathians, and Europe more widely. [ABSTRACT FROM AUTHOR]

Secondary tropical forests play an increasingly important role in carbon budgets and biodiversity conservation. Understanding successional trajectories is therefore imperative for guiding forest restoration and climate change mitigation efforts. Forest succession is driven by the demographic strategies—combinations of growth, mortality and recruitment rates—of the tree species in the community. However, our understanding of demographic diversity in tropical tree species stems almost exclusively from old‐growth forests. Here, we assembled demographic information from repeated forest inventories along chronosequences in two wet (Costa Rica, Panama) and two dry (Mexico) Neotropical forests to assess whether the ranges of demographic strategies present in a community shift across succession. We calculated demographic rates for >500 tree species while controlling for canopy status to compare demographic diversity (i.e., the ranges of demographic strategies) in early successional (0–30 years), late successional (30–120 years) and old‐growth forests using two‐dimensional hypervolumes of pairs of demographic rates. Ranges of demographic strategies largely overlapped across successional stages, and early successional stages already covered the full spectrum of demographic strategies found in old‐growth forests. An exception was a group of species characterized by exceptionally high mortality rates that was confined to early successional stages in the two wet forests. The range of demographic strategies did not expand with succession. Our results suggest that studies of long‐term forest monitoring plots in old‐growth forests, from which most of our current understanding of demographic strategies of tropical tree species is derived, are surprisingly representative of demographic diversity in general, but do not replace the need for further studies in secondary forests. [ABSTRACT FROM AUTHOR]

With increasing attention to climate change and biodiversity loss, conservation social science research on land management practices is burgeoning. Researchers have broadened their focus from protected areas to diverse types of land management to support conservation and climate mitigation. But, developing effective strategies for these issues requires an in‐depth understanding of both the socio‐psychological factors that guide landholders' decision‐making and global trends in land management practices and literature. To assess the trends and status of land management behavior research, we systematically reviewed research published between 2010 and 2020 in five seminal conservation journals. Of 11,607 articles reviewed, we identified 100 articles about land management behavior. We assessed theoretical groundings, measurement methodology, land‐use terminology and practices, ecosystem type, and geographic distribution. We identified strengths and significant gaps and weaknesses across land management research. For example, 52% of articles made no meaningful connection to theory, only 14% of papers used observed behavioral data, 86% of studies uses non‐experimental methods and researchers disproportionately measured land management behavior in developed nations (66%). We also find that language used to describe land management behavior is very heterogeneous, making it difficult to summarize land management research using traditional systematic review methods. Conducting a limited systematic review can help summarize research and also identify trends across disciplines that might otherwise missed. Results from our limited systematic review can guide future research and support the development of evidence‐based policies to mitigate climate change and biodiversity loss. [ABSTRACT FROM AUTHOR]

Societal Impact Statement: Efficient mitigation of climate change requires predictive models of forest ecosystems as sinks for atmospheric carbon. Mycorrhizal fungi are drivers of soil carbon storage in boreal forests, yet they are typically excluded from ecosystem models, because of a lack of information about their growth and turnover. Closing this knowledge gap could help us better predict future responses to climate change and guide policy decisions for sustainable management of forest ecosystems. This study provides new estimates of the production and turnover of mycorrhizal mycelial biomass and necromass. This information can facilitate the integration of mycorrhizal fungi into new predictive models of boreal forest soils. Summary: In boreal forests, turnover of biomass and necromass of ectomycorrhizal extraradical mycelia (ERM) are important for mediating long‐term carbon storage. However, ectomycorrhizal fungi are usually not considered in ecosystem models, because data for parameterization of ERM dynamics is lacking.Here, we estimated the production and turnover of ERM biomass and necromass across a hemiboreal Pinus sylvestris chronosequence aged 12 to 100 years. Biomass and necromass were quantified in sequentially harvested in‐growth bags, and incubated in the soil for 1–24 month, and Bayesian calibration of mathematical models was applied to arrive at parametric estimates of ERM production and turnover rates of biomass and necromass.Steady states were predicted to be nearly reached after 160 and 390 growing season days, respectively, for biomass and necromass. The related turnover rates varied with 95% credible intervals of 1.7–6.5 and 0.3–2.5 times yr−1, with mode values of 2.9 and 0.9 times yr−1, corresponding to mean residence times of 62 and 205 growing season days.Our results highlight that turnover of necromass is one‐third of biomass. This together with the variability in the estimates can be used to parameterize ecosystem models, to explicitly include ERM dynamics and its impact on mycorrhizal‐derived soil carbon accumulation in boreal forests. [ABSTRACT FROM AUTHOR]

The challenge of feeding an additional 2 billion people by 2050 is one of the most pressing issues of our generation. The required changes in the current food system must be achieved while reducing the negative environmental impacts of current farming practices on our climate and biodiversity and avoiding deforestation. This formidable challenge must be overcome in a projected climate that is more variable and where extreme weather events are increasingly common. While the green revolution, agricultural land expansion and agrotechnological innovations have significantly increased crop productivity over the last 50 years, the gains in the yields of most major crops have reached a plateau. Moreover, global hunger remains at a record high. Climate change‐associated changes in weather patterns have decreased the yields of major crops. Further land expansion is impossible without severe trade‐offs with biodiversity and climate change mitigation. Wars and pandemics are currently severely disrupting the global agri‐food system, increasing prices and exacerbating food insecurity, with the world's poorest suffering the most. The climate change–social instability nexus will continue to cause additional stress to the agri‐food system. Here, we consider the inequities in the current food system, highlighting the weak interconnection among research, policy and societal action that is hindering mitigation and adaptation efforts. We argue that improved interconnections among research, policy, governance and societal action will unlock the potential to achieve food security while supporting climate change mitigation targets. Our analysis includes specific strategies such as strengthening small‐scale farmers, promoting fair trade practices and reducing food waste to achieve these goals. [ABSTRACT FROM AUTHOR]

The architecture, engineering, and construction industry is undergoing a significant shift, steering buildings away from resource‐intensive processes toward becoming instruments for climate mitigation. In this transformative landscape, integrating circular bio‐based alternatives and reducing emissions through biotechnological and enzymatic processes have significant potential. Specifically, mycelium‐bound composites have emerged as renewable alternatives for new materials and added‐value wood products. Despite their numerous advantages, integrating these materials into current engineering practices presents challenges deriving from the complex nature of the material´s production process and the transfer from the laboratory to the industrial scale. In this regard, the design and engineering of novel controlled environments are fundamental in maintaining optimal growth conditions during material production. This, in turn, influences the overall material performance and potential use in construction. [ABSTRACT FROM AUTHOR]

Forestation is a key strategy for climate mitigation in China through its biogeochemical (BGC) effect of ecosystem carbon sequestration. Additionally, the BGC effect of forestation can be either reinforced or counteracted by concurrent biogeophysical processes (BGP effect) resulting in local land surface warming or cooling, which can be translated into CO2e (i.e., BGC effect) using a local transient climate response. Previous evaluations of the climate mitigation potential of future forestation in China have, however, focused on the BGC effect only and neglected the BGP effect, potentially leading to suboptimal forestation areas. Here, we determined priority forestation areas in China by incorporating both effects to maximize its global climate mitigation effect. Our results suggest an additional 167.2 Mha potentially suitable for forestation in China, exceeding the largest forestation target (86.8 Mha) possibly assumed by the government in 2060. The forestation‐induced BGP effect (18.7 ± 61.9 tCO2e ha−1) largely reinforces the BGC effect (458.2 ± 92.6 tCO2e ha−1) in China, yielding a total climate mitigation effect of 476.9 ± 114.2 tCO2e ha−1 over 40 years (2021–2060). Under the 2060 forestation target, considering both BGC and BGP effects will displace 17.7% (15.3 Mha) of the forestation area derived by considering the BGC effect alone. Integrating both BGC and BGP effects will lead to a CO2 uptake of 28.8 GtCO2e by 2060, 3.9 GtCO2e higher than the value obtained when considering the BGC effect only. Our results highlight the importance of considering BGP effect when making forestation policies for climate mitigation. Plain Language Summary: Forestation plays a crucial role in mitigating climate change through both carbon sequestration (biogeochemical or BGC effect) and modification of land surface temperature (biogeophysical or BGP effect). Maximizing forestation contribution to global climate mitigation requires maximizing the collective effects of both BGC and BGP through converting BGP to BGC, as temperature change is fundamentally driven by atmospheric CO2 changes which are further influenced by forestation BGC effect. However, previous evaluations of China's forestation potential almost completely focused on the BGC effect. This study identified optimal forestation areas to maximize their global climate mitigation effect in China by considering both BGC and BGP effects. Considering both effects will displace 17.7% (15.3 Mha) of forestation areas determined by considering only the BGC effect under the 2060 forestation target. Considering both effects also leads to a higher CO2 uptake of 3.9 GtCO2e than the value when considering the BGC effect only by 2060. Forestation‐induced BGC and BGP effects mostly work in synergy in China, mutually enhancing the overall climate benefits. Our findings have implications for future forestation policy in China to maximize its contribution to global climate mitigation. Key Points: The biogeophysical (BGP) effect should be included in the traditional forestation policies considering only biogeochemical (BGC) effectConsidering BGC and BGP effects will lead to 17.7% of forestation area being displaced, compared to considering the BGC effect only by 2060Integrating BGC and BGP effects exhibits a 15.8% (3.9 GtCO2e) increase in CO2 uptake by 2060 [ABSTRACT FROM AUTHOR]

Understanding the climate and carbon cycle response to negative CO2 emissions is important for developing climate mitigation strategies that aim to limit global warming to a specific threshold. In this study, using a coupled climate and carbon cycle model, a novel set of nine stylized simulations are conducted with cumulative emissions of 1,000 GtC, 2,000 GtC, and 5,000 GtC over 150, 250, and 500 years, followed by identical cumulative negative emissions so that the net cumulative emissions are zero. On millennial‐timescales, the climate system returns close to the preindustrial state, independent of the emission and removal pathways. However, the thermal and biogeochemical inertia of the ocean play an important role in determining the climate and carbon cycle response during the emission and removal phases. When zero net emissions are reached, surface air temperature is larger by 0–1°C than the preindustrial state, and the atmospheric CO2 concentration is less by 12–29 ppm. These changes increase with both the magnitude and duration of the emission and removal pulses. In contrast, hysteresis in the relationship between global mean surface temperature and cumulative carbon emissions increases with the magnitude but decreases with the duration of emission and removal pulses. Our study highlights the role of ocean inertia in the asymmetry in climate response to emissions and removals and indicates that an earlier emission reduction implying emission/removal pathways with smaller magnitudes and shorter durations for the positive and negative emission pulses would avoid larger climate and carbon cycle impacts on centennial‐timescales. Plain Language Summary: In this study, we examine the climate system response to a set of scenarios where emissions are followed by the removal of all carbon emitted into the atmosphere. We find that the climate system returns to preindustrial state on millennial timescales independent of emission and removal pathways. However, larger changes in the climate system at the end of removals (on centennial timescales) are simulated for a larger magnitude and longer duration of the emission and removal pulses. Since a delay in emission reduction implies a larger magnitude and longer duration for the emissions and consequently larger magnitude and longer duration for the removals to bring the climate state to preindustrial conditions, an earlier emission reduction would help to avoid large climate and carbon cycle impacts on centennial‐timescales. Key Points: The climate system response to net zero emissions is path independent on millennial timescalesOn centennial time scales, the climate system response to net zero emissions depends on the magnitude and duration of emission pulsesA larger magnitude and longer duration for the emission pulses lead to longer delays in climate response on centennial timescales [ABSTRACT FROM AUTHOR]

Forests are a large carbon sink and could serve as natural climate solutions that help moderate future warming. Thus, establishing forest carbon baselines is essential for tracking climate‐mitigation targets. Western US forests are natural climate solution hotspots but are profoundly threatened by drought and altered disturbance regimes. How these factors shape spatial patterns of carbon storage and carbon change over time is poorly resolved. Here, we estimate live and dead forest carbon density in 19 forested western US ecoregions with national inventory data (2005–2019) to determine: (a) current carbon distributions, (b) underpinning drivers, and (c) recent trends. Potential drivers of current carbon included harvest, wildfire, insect and disease, topography, and climate. Using random forests, we evaluated driver importance and relationships with current live and dead carbon within ecoregions. We assessed trends using linear models. Pacific Northwest (PNW) and Southwest (SW) ecoregions were most and least carbon dense, respectively. Climate was an important carbon driver in the SW and Lower Rockies. Fire reduced live and increased dead carbon, and was most important in the Upper Rockies and California. No ecoregion was unaffected by fire. Harvest and private ownership reduced carbon, particularly in the PNW. Since 2005, live carbon declined across much of the western US, likely from drought and fire. Carbon has increased in PNW ecoregions, likely recovering from past harvest, but recent record fire years may alter trajectories. Our results provide insight into western US forest carbon function and future vulnerabilities, which is vital for effective climate change mitigation strategies. Plain Language Summary: We investigated the role of western US forests as natural climate solutions by analyzing current forest carbon storage and trends from 2005 to 2019 across 19 forested regions. We found that the Pacific Northwest stores the most carbon, while the Southwest stores the least. Climate, wildfires, and human activities determined carbon amounts. For instance, climate is important in the Southwest and Lower Rockies, while wildfires impact the entire western US, but particularly the Upper Rockies and California. Human activities like harvesting and private ownership, decrease carbon, particularly in the Pacific Northwest. Since 2005, live carbon has declined in many western US areas, likely due to drought and fires. The study highlights the vulnerability of western US forests to climate‐related and human threats to carbon, providing crucial insights for effective climate change mitigation strategies. Understanding these dynamics is essential for scientists, policymakers, and educators working toward sustainable forest management and climate solutions in the region. Key Points: Live carbon has declined across much of western United States forests, likely due to drought and fire, resulting in an increase in dead carbonIn the Pacific Northwest (PNW), harvest led to reduced carbon, but recovery from past harvest likely caused carbon to increase since 2005Our results provide a baseline from which to evaluate future changes and inform management strategies [ABSTRACT FROM AUTHOR]

The article explores the potential of carbon capture and storage (CCS) technologies in addressing climate change. While the UN Panel on Climate Change emphasizes the importance of CCS in limiting global warming, there are concerns about its cost-effectiveness and ability to significantly reduce emissions. Despite this, countries like the UK and the US are showing support for CCS through government initiatives and funding. The article emphasizes the need for regulatory frameworks and financial support from governments to encourage private investment in CCS. It also discusses the current state of carbon capture, utilization, and storage (CCUS) technology and the need for increased government support to promote its widespread use. The article provides a balanced perspective on the opportunities and challenges associated with CCUS. [Extracted from the article]

Accurate modeling of snow depth (SD) processes is critical for understanding global energy balance changes, affecting climate change mitigation strategies. This study evaluates the Coupled Model Intercomparison Project Phase 6 (CMIP6) model performance in simulating daily SD across Canada. We assess CMIP6 outputs against observed data, focusing on daily SD averages, snow cover durations, and rates of accumulation and depletion, alongside annual SD peaks for 11 major Canadian catchments. Our findings reveal that CMIP6 simulations generally overestimate daily SD by 57.7% and extend snow cover duration by 30.5 days on average. While three models (CESM2, UKESM1‐0‐LL and MIROC6) notably align with observed annual SD peaks, simulation biases suggest the need for enhanced model parameterization to accurately capture snow physics, particularly in regions with permanent snow cover and complex terrains. This analysis underscores the necessity of refining CMIP6 simulations and incorporating detailed geographical data for better SD predictions. Plain Language Summary: Precise simulations of snow depth (SD) are crucial for understanding changes in the Earth's energy balance and helping efforts to combat climate change. In this research, we evaluate how well the latest phase of the Coupled Model Intercomparison Project (CMIP6) can simulate the daily SD across Canada. By comparing these simulations to various SD data sets, we looked at average daily SD, how long snow remains on the ground, and how quickly it accumulates or melts away, focusing on 11 major catchments in Canada. Our study found that the CMIP6 models tend to simulate more SD, by about 57.7% on average, and suggest that snow cover remains around 30.5 days longer than observed durations. Although three specific models excel in matching the annual peak of daily SD, we noticed biases that point to a need for improving how these models represent various land covers. Our findings highlight the importance of making these models more accurate by using more detailed information about land cover properties, which helps better predict SD and understand its role in climate change. Key Points: Coupled model intercomparison project phase 6 (CMIP6) simulations mostly overestimate the average daily SD values by a median of 57.7% (6.9 cm)The average snow cover duration is overestimated by 30.5 days compared to station data, confirmed by the CMC data setCMIP6 simulations relatively capture extremes well, with a median bias of 12.73% [ABSTRACT FROM AUTHOR]

Natural forests are crucial for climate change mitigation and adaptation, but deforestation and degradation challenges highly reduce their value. This study evaluates the potential of natural forest carbon stock and the influence of management interventions on enhancing forest carbon storage capacity. Based on forest area cover, a study was conducted in nine purposely selected forest patches across various forest ecosystems. Data on diameter, height, and environmental variables from various forest management approaches were collected and analyzed with R Ver. 4.1. The findings revealed a substantial difference (p.029) in carbon stock between environmental variables and management interventions. The findings revealed a strong connection between environmental variables and the overall pool of carbon stock within forest patches (p.029). Carbon stocks were highest in the Moist‐montane forest ecosystem (778.25 ton/ha), moderate slope (1019.5 ton/ha), lower elevation (614.50 ton/ha), southwest‐facing (800.1 ton/ha) and area exclosures (993.2 ton/ha). Accordingly, natural forests, particularly unmanaged parts, are sensitive to anthropogenic stresses, decreasing their ability to efficiently store carbon. As a result, the study highlighted the importance of sustainable forest management, particularly area exclosures and participatory forest management, in increasing forest carbon storage potential. [ABSTRACT FROM AUTHOR]

Land use and land cover changes (LULCCs) can influence surface temperature through local and nonlocal biophysical processes, which remain inadequately addressed. In this study, we separate the local and nonlocal effects of historical (1850–2014) LULCCs based on model outputs from the Coupled Model Intercomparison Project Phase 6. We also attempt to explore the sources of intermodel differences in the effects of LULCCs. The multimodel mean shows a cooling effect of −0.05°C (with an intermodel range of −0.24–0.06°C) at the global scale due to cropland and pastureland expansion, consisting of dominant nonlocal cooling of −0.06°C (with an intermodel range of −0.26–0.06°C) and slight local warming of 0.01°C (with an intermodel range of −0.01–0.05°C). The modeling results show some clear consistency in the effects of LULCCs despite considerable intermodel uncertainties. The local effects cause warming at low latitudes and cooling in boreal regions via changes in upward shortwave radiation and sensible and latent heat fluxes. The nonlocal effects mainly cause cooling via decreases in downward longwave radiation and increases in upward shortwave radiation. Intermodel differences in the total effects are dominated by those in the nonlocal effects, which are further attributed to divergent changes in downward longwave radiation and sensible heat flux across the models. This study highlights the importance of the nonlocal effects of LULCCs in terms of strength and intermodel uncertainty, with implications for designing land‐based solutions aimed at climate change mitigation. Plain Language Summary: Land use and land cover changes (LULCCs) can alter surface properties and thereby influence surface temperature through land–atmosphere interactions. LULCCs influence the climate not only at the location of LULCCs (local effects) but also elsewhere (nonlocal effects) through atmospheric and oceanic feedbacks. However, the local and nonlocal effects of realistic LULCCs still lack explicit investigation. In this study, we quantify the local and nonlocal effects of historical (1850–2014) LULCCs and their intermodel differences based on a set of simulations from four earth system models. The multimodel mean suggests that historical cropland and pastureland expansion has caused a nonlocal cooling effect of −0.06°C and a local warming effect of 0.01°C, creating a net cooling effect of −0.05°C at the global scale. The local and nonlocal effects of LULCCs can be attributed to changes in surface fluxes and atmospheric feedbacks, whereas the strength and sign vary substantially across the models. Large intermodel differences in the total effects of LULCCs mostly result from those in the nonlocal effects. This study highlights the importance of the nonlocal effects of LULCCs and has implications for developing land‐use strategies aimed at climate change mitigation. Key Points: The local and nonlocal biophysical effects of historical land use and land cover changes (LULCCs) are investigated using CMIP6 modelsThe multimodel mean shows that, overall, historical LULCCs cool the land surface through nonlocal processesThe intermodel divergence in the total effects of historical LULCCs mainly results from low intermodel agreement on the nonlocal effects [ABSTRACT FROM AUTHOR]

An accurate quantification of global methane sources and sinks is imperative for assessing realistic pathways to mitigate climate change. A key challenge of quantifying the Global Methane Budget (Saunois et al., 2020, https://doi.org/10.5194/essd‐12‐1561‐2020) is the lack of consistency in uncertainties between sectors. Here we provide a new perspective on bottom‐up (BU) and top‐down (TD) methane uncertainties by using an expert opinion analysis based on a questionnaire conducted in 2021. Expectedly, experts rank highest uncertainty and lowest confidence levels in the Global Methane Budget related to natural sources in BU budgets. Here, we further reveal specific uncertainty types and introduce a ranking system for uncertainties in each sector. We find that natural source uncertainty is related particularly to driver data uncertainty in freshwater, vegetation, and coastal/ocean sources, as well as parameter uncertainty in wetland models. Reducing uncertainties, most notably in aquatic and wetland sources will help balance future BU and TD global methane budgets. We suggest a new methane source partitioning over gradients of human disturbance and demonstrate that 76.3% (75.8%–79.4%) or 561 (443–700) Tg CH4 yr−1 of global emissions can be attributed to moderately impacted, man‐made, artificial, or fully anthropogenic sources and 23.7% (20.6%–24.2%) or 174 (115–223) Tg CH4 yr−1 to natural and low impacted methane sources. Finally, we identify current research gaps and provide a plan of action to reduce current uncertainties in the Global Methane Budget. Plain Language Summary: To effectively address climate change, it's crucial to gain a better understanding of the difficulties involved in estimating global methane sources and sinks. One of the key challenges in this process are the varying levels of uncertainty associated with different sectors responsible for methane emissions and methane uptake. In this study, we conducted a survey to gather expert opinions regarding the uncertainty of methane data. The experts highlighted that the Global Methane Budget has the highest uncertainty and lowest confidence levels when it comes to natural sources in the bottom‐up budgets. This uncertainty primarily stems from uncertain data related to natural sources like freshwater, vegetation, and coastal/ocean areas, as well as the parameters used in wetland models. We show that 76.3% of all global methane emissions are related to human‐impact or fully man‐made. Additionally, we identify existing gaps in research and lay out a plan of action to reduce the current uncertainties associated with the Global Methane Budget. This effort will contribute to a more accurate understanding of methane's role in climate change mitigation. Key Points: Highest uncertainty and lowest confidence levels were identified in bottom‐up natural emissions in the Global Methane BudgetHigh driver data uncertainties are associated with freshwater, vegetation, and coastal/ocean methane sourcesNew methane source partitioning reveals 76% of global emissions are related to moderate to high levels of anthropogenic impacts [ABSTRACT FROM AUTHOR]

Stratospheric aerosol injection (SAI) has been proposed as a potential supplement to mitigate some climate impacts of anthropogenic warming. Using Community Earth System Model ensemble simulation results, we analyze the response of temperature and precipitation extremes to two different SAI strategies: one injects SO2 at the equator to stabilize global mean temperature and the other injects SO2 at multiple locations to stabilize global mean temperature as well as the interhemispheric and equator‐to‐pole temperature gradients. Our analysis shows that in the late 21st century, compared with the present‐day climate, both equatorial and multi‐location injection lead to reduced hot extremes in the tropics, corresponding to overcooling of the mean climate state. In mid‐to‐high latitude regions, in comparison to the present‐day climate, substantial decreases in cold extremes are observed under both equatorial and multi‐location injection, corresponding to residual winter warming of the mean climate state. Both equatorial and multi‐location injection reduce precipitation extremes in the tropics below the present‐day level, associated with the decrease in mean precipitation. Overall, for most regions, temperature and precipitation extremes show reduced change in response to multi‐location injection than to equatorial injection, corresponding to reduced mean climate change for multi‐location injection. In comparison with equatorial injection, in response to multi‐location injection, most land regions experience fewer years with significant change in cold extremes from the present‐day level, and most tropical regions experience fewer years with significant change in hot extremes. The design of SAI strategies to mitigate anthropogenic climate extremes merits further study. Plain Language Summary: Injecting SO2 into the stratosphere to deflect incoming sunlight back to space has been proposed as a possible means to counteract anthropogenic warming. Previous studies focused on the response of the mean climate change to SO2 injection. Here we analyze how SO2 injection would affect climate extremes using two sets of climate model simulations under a high‐CO2 scenario. In one set of simulations, SO2 is injected into the stratosphere at the equator to stabilize global mean warming at the present‐day level; in another set of simulations, SO2 is injected into the stratosphere at four different latitudes to stabilize global mean temperature, interhemispheric temperature gradient, and equator‐to‐pole temperature gradient at the same time. Our analysis shows that both equatorial injection and multi‐location injection can help reduce temperature and precipitation extreme events induced by global warming, but their effectiveness varies across different regions. In general, compared to equatorial injection, multi‐location injection can be more effective in stabilizing climate extremes at the present‐day level over most regions. This is consistent with the fact that multi‐location injection exhibits smaller changes in mean climate state than that of the equatorial injection relative to the present‐day state. Key Points: We examine the climate extreme response to two stratospheric aerosol injection (SAI) strategies: equatorial injection and multi‐location injectionThe response of climate extremes to SAI shows similar characteristics to mean climate responseMulti‐location injection is more effective in stabilizing climate extremes at the present‐day level [ABSTRACT FROM AUTHOR]

Existing estimates of the climate mitigation potential from cropland carbon sequestration (C‐sequestration) are limited because they tend to assume constant rates of soil organic carbon change over all available cropland area, use relatively coarse land delineations, and often fail to adequately consider the agronomic and socioeconomic dimensions of agricultural land use. This results in an inflated estimate of the C‐sequestration potential. We address this gap by defining a more appropriate land base for cover cropping in the United States for C‐sequestration purposes: stable croplands in annual production systems that can integrate cover cropping without irrigation. Our baseline estimate of this suitable stable cropland area is 32% of current U.S. cropland extent. Even an alternative, less restrictive definition of stability results in a large reduction in area (44% of current U.S. croplands). Focusing cover crop implementation to this constrained land base would increase durability of associated C‐sequestration and limit soil carbon loss from land conversion to qualify for carbon‐specific incentives. Applying spatially‐variable C‐sequestration rates from the literature to our baseline area yields a technical potential of 19.4 Tg CO2e yr−1 annually, about one‐fifth of previous estimates. We also find the cost of realizing about half (10 Tg CO2e yr−1) of this potential could exceed 100 USD Mg CO2e−1, an order of magnitude higher than previously thought. While our economic analyses suggest that financial incentives are necessary for large‐scale adoption of cover cropping in the U.S., they also imply any C‐sequestration realized under such incentives is likely to be additional. Plain Language Summary: As a "Nature‐based Climate Solution" (NCS), the practice of cover cropping has received widespread attention and investment recently. Through cover cropping, croplands may be able to absorb and hold more carbon in soil, drawing down CO2 in the atmosphere (i.e., sequester carbon). However, the sequestration that is feasible, which reflects socioeconomic and land use considerations, remains unquantified. We estimate this feasible potential for carbon sequestration in the U.S. croplands from cover cropping and find it to be a fraction of previous estimates. A large portion of the reduction is due to our use of a more realistic and rigorous definition of the land area suitable for cover cropping for climate mitigation purposes. This land area comprises "croplands remaining croplands" (or stable croplands) that are planted to annual crops, like corn and soybeans, because they can more easily integrate the practice. We exclude irrigated croplands to conserve water resources. At just under 44 million ha, our baseline area estimate is 32% of the current U.S. cropland extent. The rest of the reduction is associated with our use of more conservative rates of increase in soil carbon from cover cropping than earlier studies that are more realistic for assessing soil carbon sequestration potential over large areas. Our economic analyses suggests that without financial incentives, implementing cover cropping could be expensive for most U.S. farmers. This high cost hurdle needs to be evaluated against the cost‐effectiveness of alternatives that compete for the same limited resources for climate mitigation. Key Points: For U.S. croplands, the feasible potential of carbon sequestration from cover cropping is a fraction of previous estimatesDefining the land base suitable for mitigation practices more realistically and rigorously is critical to estimating the feasible potentialCover cropping, though beneficial for soil health, may not be a low‐cost pathway for climate mitigation at scale in the U.S. [ABSTRACT FROM AUTHOR]

Understanding the impact of various climate forcing agents, such as aerosols, on extreme precipitation is socially and scientifically vital. While anthropogenic absorbing aerosols influence Earth's energy balance and atmospheric convection, their role in extreme events remains unclear. This paper uses convective‐resolving radiative‐convective‐equilibrium simulations, with fixed solar radiation, to investigate the influence of absorbing aerosols on extreme precipitation comprehensively. Our findings reveal an underappreciated mechanism through which absorbing aerosols can, under certain conditions, strongly intensify extreme precipitation. Notably, we demonstrate that a mechanism previously reported for much warmer (hothouse) climates, where intense rainfall alternates with multi‐day dry spells, can operate under current realistic conditions due to absorbing aerosol influence. This mechanism operates when an aerosol perturbation shifts the lower tropospheric radiative heating rate to positive values, generating a strong inhibition layer. Our work highlights an additional potential effect of absorbing aerosols, with implications for climate change mitigation and disaster risk management. Plain Language Summary: Aerosols, particles suspended in the atmosphere, can interact with the incoming solar radiation by scattering or absorbing it. Aerosol species that absorb solar radiation generate local warming of the atmosphere. This local warming changes the vertical profile of temperature and by that affects cloud and precipitation development. In this paper we use idealized computer simulations to investigate the effect of absorbing aerosols on precipitation, and specifically on extreme precipitation events in the tropics. We demonstrate that under certain conditions, absorbing aerosols can strongly enhance extreme precipitation even despite reducing the mean. We show that this trend can be explained by a mechanism previously reported for much warmer climate conditions than currently found on Earth, involving heating by radiation of the lower part of the troposphere. These results have implications for climate change mitigation and disaster risk management. Key Points: The effect of absorbing aerosol on extreme precipitation is examined in idealized convective‐resolving radiative‐convective‐equilibrium simulationsAerosol perturbation that shifts the lower tropospheric radiative heating rate to positive values strongly enhances extreme precipitationThis trend is explained by a mechanism reported before for hothouse climate conditions involving a shift into an "episodic deluge" regime [ABSTRACT FROM AUTHOR]

Antarctic meltwater discharge has been largely emphasized for its potential role in climate change mitigation, not only by reducing global warming, but also by stabilizing the Atlantic Meridional Overturning Circulation (AMOC). Despite the tremendous impact of the AMOC on the climate system, its temporal evolution in response to the meltwater remains poorly understood. Here, we investigate the meltwater impacts on the AMOC based on the GFDL CM2.1 experiments and discover its fast weakening and slow strengthening to the Antarctic meltwater discharge. Cold ocean surface caused by meltwater spread throughout the globe and eventually strengthened the AMOC. However, in the early stages, the tropical temperature response could stimulate the Rossby wave teleconnection, modulating atmospheric circulation in the North Atlantic, and weakening convection and even the AMOC. This counterintuitive evolution implies a potential destabilizing effect of Antarctic meltwater, underscoring the importance of the atmospheric dynamics in the interaction between the two poles. Plain Language Summary: The climate system is made up of interactions between different subsystems, so that regional climate changes can have global effects. The freshwater discharge from Antarctica would increase in the future and result in regional cooling. Atmospheric and oceanic dynamics extend this local effect to the globe, reducing global surface temperature and strengthening the large‐scale ocean circulation in the Atlantic. These mitigating effects naturally put the spotlight on Antarctic meltwater. Our study however suggests that the mitigation effect depends on the time scale. Although the global mean temperature is always reduced, the ocean circulation in the Atlantic surprisingly slows down as an early response to Antarctic meltwater; fast atmospheric teleconnection enables it. This non‐monotonic evolution emphasizes the importance of the atmospheric teleconnection between the two poles, which should be carefully considered to understand the polar climate. Key Points: The response of the Atlantic Meridional Overturning Circulation to perennial meltwater‐induced cooling is investigated by GFDL CM2.1 experimentsBefore the cooling spreads out the Atlantic, tropical atmospheric teleconnection could weaken the Greenland ocean convectionThe fast and slow responses imply the importance of the atmospheric teleconnection to regulate polar climate [ABSTRACT FROM AUTHOR]

Recent studies suggest that hypolimnetic respiration may be responsible for greenhouse gas (GHG) emissions from deep reservoirs. Currently, quantitative evaluation of aerobic vs. anaerobic processes and priming (enhanced processing of organic matter due to the addition of labile carbon) in regulating GHG production and emissions across the reservoir‐downstream continuum remains largely unknown. High‐resolution, annual time‐series observations in a large, subtropical reservoir (Shuikou) experiencing seasonal hypoxia in southeast China indicate that aerobic hypolimnetic CO2 production dominated in most periods of the stratified spring/summer with higher rates at higher temperatures. In addition, anaerobic production of hypolimnetic CO2 occurred in the late stratified spring/summer period, which stimulated hypolimnetic production of CH4 and N2O. Incubation experiments showed that priming in spring enhanced both aerobic and anaerobic production of excess GHGs. A late spring flood event generated the highest daily efflux of CO2 through the flushing of GHG‐enriched hypolimnion waters. Turbine degassing contributed 59%, 93%, and 63% of annual CO2, CH4, and N2O effluxes, respectively. Moreover, annual downstream GHG emissions were similar to those in the transition/lacustrine zone of the Shuikou reservoir. Diurnal variation observations revealed net CO2 emissions even during algal bloom seasons. The reservoir‐downstream river continuum was a year‐round source of GHGs (218.5 ± 18.9 Gg CO2‐equivalent yr−1; CO2 contributed 91%). However, the loss of oxygen also leads to increased production and storage of recalcitrant dissolved organic carbon (RDOC). Thus, identifying mechanisms controlling both GHG emissions and RDOC production is crucial to constrain the carbon neutrality issue of hydroelectric reservoirs in the context of climate change mitigation strategies. [ABSTRACT FROM AUTHOR]

Land use change (LUC) alters the global carbon (C) stock, but our estimation of the alteration remains uncertain and is a major impediment to predicting the global C cycle. The uncertainty is partly due to the limited number and geographical bias of observations, and limited exploration of its predictors. Here we generated a comprehensive global database of 5,980 observations from 790 articles. The number of sites evaluated is at least seven times larger than in previous meta‐analyses. Our constrained estimates of different LUC's effects on soil organic C (SOC) and their variations across global climates reveal underestimation/overestimation in previous estimates. Converting forests and grasslands to croplands reduced SOC by 24.5% ± 1.53% (−11.03 ± 1.06 Mg ha−1) and 22.7% ± 1.22% (−8.09 ± 0.67 Mg ha−1), while 28.0% ± 1.56% (4.46 ± 0.42 Mg ha−1) and 33.5% ± 1.68% (5.8 ± 0.38 Mg ha−1) increases, respectively, were obtained in the reverse processes. Converting forests to grasslands decreased SOC by 2.1% ± 1.22% (−1.13 ± 0.44 Mg ha−1), while the reverse process increased SOC by 18.6% ± 1.73% (3.31 ± 0.51 Mg ha−1). Modeled relative importance of 10 drivers of LUC's impact on SOC revealed that higher initial SOC (iSOC) does not solely determine SOC loss in SOC‐negative LUC scenarios as previously proposed. Across four decades, reconverting croplands to forests and grasslands recovered only 49.5% (6.1 ± 0.51 Mg ha−1) and 75.3% (7.0 ± 0.38 Mg ha−1) of the iSOC, respectively, indicating the need for protecting C‐rich ecosystems. Our global data set advances information on LUC's effect on SOC and can be valuable to constrain Earth system models to reliably estimate global SOC stocks and plan climate change mitigation strategies. Plain Language Summary: Land use change (LUC) could increase or decrease the global soil organic carbon (SOC) stock and affect carbon cycling and climate change, but estimating its effect size is the most uncertain aspect of the global carbon cycle. Available estimates vary among studies, most of which often use few observations that do not cover most global regions. To provide more accurate estimates of different LUC types' effects on SOC, we compiled a comprehensive database that contains 5,980 observations across all global regions; and revealed that previous studies have underestimated/overestimated these effects. We modeled the predictors of SOC change and found that previous conclusions that higher initial SOC is the main reason for higher organic carbon loss under negative LUC scenarios were inexact. We show that land use practices aimed at restoring SOC could only recover part of the amount lost during similar time frames; hence, it is important to protect carbon‐rich ecosystems. Our study provides robust estimates of LUC's effect on SOC and provides data sets that can reliably assess and model the global carbon cycle and plan strategies for controlling global climate change. Key Points: Comprehensive global database advances robust estimates of land use change's (LUCs) effect on soil organic carbon (SOC) vital for Earth system modelingHigher initial SOC does not solely control rapid SOC loss in carbon‐negative LUC as often proposedDespite SOC buildup in the past four decades, the amount lost cannot be regained by restoration during similar time frames [ABSTRACT FROM AUTHOR]

Drought has a paramount impact on global agriculture and food security. However, the study on future cropland areas that can incur drought is inadequate. This paper uses input parameters from 7 CMIP6 models for 7 future scenarios (SSP1‐1.9, SSP1‐2.6, SSP4‐3.4, SSP2‐4.5, SSP4‐6.0, SSP3‐7.0, and SSP5‐8.5) to measure South Asian cropland exposure to drought and its underlying factors. Some defined epochs such as 2021–2040 (near‐term), 2041–2060 (mid‐term), 2081–2100 (long‐term), and 1995–2014 (reference period) are designed to explore diverse outlooks of the change. The Standardized Precipitation Evapotranspiration Index and the Run theory methods are applied to detect drought. Results indicate an intensified cropland (under SSP4‐3.4, SSP3‐7.0, and SSP5‐8.5) in the Indo‐Gangetic Plain region of South Asia, where mostly the variation occurs among scenarios and periods. Notably, the future cropland exposed to drought will increase in the 2021–2040, and 2041–2060 periods, but it intends to decline during the 2081–2100. Relatively, the exposed cropland will upturn highest by 49.2% (SSP3‐7.0) in the mid‐term period and decrease by −8.2% (SSP5‐8.5) in the end future. Spatially, distributed cropland in the central, south‐west, and portion of the northeast of South Asia are subjective to be exposed largely, but it can drop greatly across the eastern part by the end future. Importantly, the climate change effect plays a grounding role in future exposure change over the region during the near to mid‐term periods, while the cropland change effect is predominant in the long‐term perspectives. However, these findings signify the urgency of policymaking focusing on drought mitigation to ensure food security. Plain Language Summary: Estimating drought‐induced cropland exposure is the pivotal aspect of agricultural risk assessment for drought impacts. The purposes of this study are to explore (a) how much of the cropland area would be exposed to drought under SSP scenarios; and (b) the degree to which climate change and cropland change effects contribute to changes in exposure. In this regard, we conducted a multi‐model and multi‐scenario‐based analysis to reveal variations in the cropland area exposed to drought in South Asia. Among the seven scenario combinations, the highest percentage of cropland exposed to drought was found at 49.2% (SSP3‐7.0) in the mid‐term epoch (2041–2060). The climate change effect seems to be the key contributor in the near‐term to mid‐term period, whereas it is the cropland change effect long‐term. To reduce drought risk, we recommend focusing on strong climate change mitigation policy development in the near‐ and mid‐term periods at a global scale and strict land‐use management policy interventions in the long‐term period at the regional level. Key Points: Larger cropland area will experience drought in the 2040–2060 period, while it will decline by the end of 21st centuryThe exposed cropland will increase by 49.2% under SSP3‐7.0 than that of historical timeThe climate change effect is the pivotal contributor in exposure changes over South Asia [ABSTRACT FROM AUTHOR]

It is no longer a myth that climate change‐related disasters are on the rise globally, with severe and devastating consequences in developing countries, particularly in Sub‐Saharan Africa, where many of the world's poor people reside. Thus, the emphasis on adaptation to climate change is no longer a choice or a deferred problem into the future, but rather an urgent matter of concern which must be considered a policy priority. As a response to retrogressive climate change challenges on social‐economic development and environmental degradation, the government of South Africa has in the last two and half decades, embarked on the progressive formulation of different policy instruments and strategic frameworks to curb and minimize the impacts of climate change on all sub‐sectors of the economy. Although much remains to be achieved, some level of success has been realized, particularly in the space of policy formulation, albeit the poor record of implementation. Using research methods inspired by the tradition of qualitative research and an appraisal of existing literature, this paper discusses the complexities of climate change adaptation governance at a local government level in South Africa, focusing on the Eastern Cape Province. It is argued in the paper that one of the major challenges for climate change governance at local municipality levels in South Africa emanates from the gap between aspirations and actions across the entire national governance system. The absence of an integrated climate change governance system has posed significant systemic challenges, and these have tended to constrain decision‐making and implementation processes. These issues have been discussed within the broader discourse of the sustainable development goals, particularly goals number 13, 16 and 17. [ABSTRACT FROM AUTHOR]

Gender‐differentiated roles, responsibilities, access, rights, and knowledge gaps shape women's vulnerability to climate change. This is especially critical for women farmers whose livelihoods are climate‐dependent. A key component in building women farmers' resilience to climate change is deepening their adaptive capacity. Therefore, this research sought to measure the adaptive capacity of women farmers from two unique districts of Ghana using the sustainable livelihood capitals and investigate how access to climate information and the uptake of climate action can influence women's adaptive capacity. Rural women farmers (n = 497) were interviewed through a survey and supported with key informant interviews from six agricultural staff at the selected districts. The adaptive capacity of respondents was rated moderate at 0.405. Differences between the adaptive capacity of women from different agroecological zones (Dormaa East—0.422; East Gonja—0.388) were statistically insignificant (p > 0.05). All climate information mediums except the TV medium had a significant prediction on women farmers' adaptive capacity. The odds of a decreasing relationship of predictor variables, such as extension officer medium, radio, and adaptation action, require strategic structuring to accrue holistic benefit. The study thus recommends deepening women's benefit from extension services by attracting and retaining female extensionists, while training extensionists on tailored techniques for engaging female farmers. Again, extensionists who report high outreach to female farmers should be incentivized. Traditional and modern Information and Communication Technology mediums must be explored and integrated as alternatives. Co‐benefit practices for both adaptation and mitigation should be encouraged among women farmers to deepen climate action. [ABSTRACT FROM AUTHOR]

This study theorizes and empirically tests whether firms' decisions to join multi‐stakeholder initiatives, targeting climate mitigation, lead to improved environmental performance. We focus on firms' participations in the Science Based Targets initiative, a multi‐stakeholder initiative meant to support firms in setting greenhouse gas (GHG) emission reduction targets in line with the thresholds defined by the Paris Agreement in 2015. The study hypothesizes that participation reduces firm's concerns about uncertainty and encourages investments in timeous internal climate change activities. We used the coarsened exact matching methodology to create a matched sample of European and North American listed firms participating in the initiative and comparable, non‐participating firms over a 3‐year period from 2015 to 2017. The results showed that firms' participation led to lower levels of GHG emissions compared to similar non‐participating counterparts, especially when they committed to the initiative with the intention to follow the proposed indications. [ABSTRACT FROM AUTHOR]

There are global aspirations to reach net zero emissions, which triggered the development of standards, guidance and tools to measure and manage climate action across countries, sectors and companies. However, carbon accounting inaccuracies, ambiguous emissions disclosures and unambitious climate targets are hampering these aspirations. This paper reports on the disparity between high‐level guidance and practical implementation of carbon accounting and reporting at company level. By conducting a systematic literature analysis and focussing on the English Water sector, we utilise case study data from Northumbrian Water Limited (NWL), to identify limitations in the current guidance and frameworks. The results indicate the necessity for enhanced alignment in high‐level guidance, particularly regarding the Greenhouse Gas Protocol and the Science‐Based Target Initiative. It is evident that clarity and consistency from high‐level resources are essential for climate mitigation. This paper shows, depending on the sector and company types, that different benefits are gained from using the available resources. We propose a carbon measurement and management process for the English Water sector (and beyond) to reach net zero targets and make recommendations for decision makers. This helps to understand best practices of carbon accounting and reporting and to make effective investment decisions. Consequently, we advocate for policy interventions to improve the standardisation of carbon accounting models. Harmonising international regulatory frameworks and standards is needed, which will empower organisations to effectively assess, manage and reduce their carbon footprints. [ABSTRACT FROM AUTHOR]

Assessing the effects of weather and climate on agricultural production is crucial for designing policies related to climate change adaptation and mitigation. A large body of literature has identified the detrimental effects of climate change on crop yields worldwide, and farm‐level adaptation has been shown to mitigate the adverse effects on agricultural production. In this study, we employ a structural model to examine farm production responses to ongoing weather trends. We investigate how farmers adjust output and input decisions by estimating a system of output supply and input demand functions, controlling for nonrandom crop selection. Using panel data with 14,796 observations reflecting 1638 German crop farms (1996–2019), we find that both the expected and realized weather determine farmers' production decisions. In the event of a drought, the supply of most considered crops and the demand for fertilizer decrease. The drought shock has also lasting effects on farmers' production decisions, with a reduced supply of protein crops and an increased level of root crops production in subsequent years. These findings highlight the need to account for farm‐level production responses when assessing weather and climate impacts. [ABSTRACT FROM AUTHOR]

The concentration of chlorophyll‐a (CHL) is an important proxy for autotrophic biomass and primary production in the ocean. Quantifying trends and variability in CHL are essential to understanding how marine ecosystems are affected by climate change. Previous analyses have focused on assessing trends in CHL mean, but little is known about observed changes in CHL extremes and variance. Here we apply a quantile regression model to detect trends in CHL distribution over the period of 1997–2022 for several quantiles. We find that the magnitude of trends in upper quantiles of global CHL (>90th) are larger than those in lower quantiles (≤50th) and in the mean, suggesting a growing asymmetry in CHL distribution. On a regional scale, trends in different quantiles are statistically significant at high latitude, equatorial, and oligotrophic regions. Assessing changes in CHL distribution has potential to yield a more comprehensive understanding of climate change impacts on CHL. Plain Language Summary: The marine environment is essential to nature and society, as it provides food and other important services such as Earth's climate regulation and habitat for species. Marine primary productivity is increasingly stressed due to global climate change. Detecting the impact of climate change on primary producers should be a priority given their critical role in the climate system. Most studies focus on the impact of climate change by evaluating the mean state of primary productivity, but little is known about whether and how climate change is impacting variance and extremes. Here we assess changes in chlorophyll‐a (CHL), which is an important proxy for primary production of marine ecosystems. We quantify long‐term changes in different aspects of the CHL distribution (mean, variance, and extremes) using a quantile regression model. We find that CHL high extremes and variability are slightly intensified globally during the 26 years of observational record. Trends in regional scales, especially in high‐latitude and North Atlantic Subtropical Gyre, show that CHL high extremes have been increasing since 1997. Our results suggest that more emphasis should be put into understanding the impact of climate change on the variance and extremes of primary productivity for climate change adaptation and mitigation. Key Points: Long‐term changes are detected in different aspects of the distribution of chlorophyll‐a (not just the mean state)Oceanic chlorophyll‐a high extremes are changing faster than chlorophyll‐a mean globally during 1997–2022On a regional scale, chlorophyll‐a extremes trends are predominant at high latitude (+), equatorial (−), and oligotrophic regions (−) [ABSTRACT FROM AUTHOR]

Aim: Colombia has committed to ambitious forest restoration targets which include a 1 million ha Bonn Challenge commitment and 6.47–8.31 million ha (rehabilitation and restoration, respectively) under the National Restoration Plan. Determining where and how to implement programs to achieve these targets remains a significant challenge. Location: Colombia. Methods: We adopt a multi‐objective optimisation framework for restoration planning and apply it to Colombia. We explore cost‐effective solutions that leverage the potential for assisted natural regeneration benefits while accounting for opportunity and establishment costs of restoration and maximising biodiversity conservation and climate change mitigation benefits. We explore four politically relevant restoration area‐based targets (1, 6, 6.47 and 8.31 million ha) and identify minimum cost, and suites of maximum benefit and cost‐effective solutions. Results: We identify solutions that simultaneously perform well across biodiversity and carbon objectives, despite trade‐offs between these objectives. We find that cost‐effective solutions can achieve on average 91.1%, 90.8%, 90.5% and 90.1% of maximum carbon benefit and 100% of the maximum biodiversity benefit while significantly reducing costs. On average, the cost‐effective solutions reduce the cost by 87.5%, 56.8%, 59.6% and 46.2% compared to the maximum benefit solutions considering one, six, 6.47 and 8.31 million ha restoration targets, respectively. Main Conclusions: Colombia has committed to bold restoration and conservation targets, such as those under the new 2030 Convention on Biological Diversity Global Biodiversity Framework. Strategic forest restoration planning will play an important role in achieving Colombia's biodiversity conservation and climate mitigation goals. We provide quantitative evidence to inform planning for environmentally and economically sensible restoration policy and practice in the country. Our framework and results can help guide Colombia towards meeting its ambitious forest restoration targets cost‐effectively. [ABSTRACT FROM AUTHOR]

A fraction of CO2 uptake by terrestrial ecosystems is exported as organic carbon (C) through the terrestrial‐aquatic continuum. This translocated C plays a significant role in the terrestrial C balance; however, obtaining global assessments remains challenging due to the predominant reliance on empirical approaches. Leaching of dissolved organic C (DOC) from soils to rivers represents an important fraction of this C export and is assumed to drive a large proportion of the net‐heterotrophy of river systems and the related CO2 emissions. Using the model JULES‐DOCM, we projected DOC leaching trends over the 21st century based on three scenarios with high (RCP 2.6), intermediate (RCP 4.5), and low (RCP 8.5) climate mitigation efforts. The RCP 8.5 scenario led to the largest DOC leaching increase of +42% to 395 Tg C yr−1 by 2100. In comparison, RCP 2.6 and RCP 4.5 led to increases of 10% and 21%, respectively. Under RCP 8.5, the sub‐tropical zone showed the highest relative increase of 50% above current levels. In the boreal and tropical zones, the simulations revealed similar increases of 48% and 41%, respectively. However, given the pre‐eminence of the tropics in DOC leaching, the absolute increment is markedly substantial from this region (+59 Tg C yr−1). The temperate zone displayed the lowest relative increase with 35%. Our analysis identified the rising atmospheric CO2 concentration and its fertilizing effect on terrestrial NPP as the main reason for the future increase in DOC leaching. Plain Language Summary: Terrestrial ecosystems absorb CO2 and some of this is transformed into dissolved organic carbon (DOC) that leaches from soils to inland waters, driving aquatic CO2 emissions. Using the JULES‐DOCM model, we analyzed future DOC leaching trends under different climate scenarios. The scenario of low climate change mitigation led to the most significant leaching increase by the end of the century. Among various regions, the sub‐tropical areas showed the greatest relative growth in DOC leaching, with the tropics also seeing a substantial rise. This increase in DOC leaching is mainly driven by rising atmospheric CO2 levels, which boosts plant growth and productivity on land. Key Points: We predict an increase of global soil dissolved organic carbon (DOC) leaching of up to 42% or 395 Tg C yr−1 by 2100The sub‐tropical zone experienced the greatest relative DOC leaching growth, while the tropics had a notable absolute increaseThe primary driver for the future surge in DOC leaching is the rising atmospheric CO2 and its fertilizing effect on terrestrial NPP [ABSTRACT FROM AUTHOR]

Prescribed fire has been increasingly promoted to reduce wildfire risk and restore fire‐adapted ecosystems. Yet, the complexities of forest ecosystem dynamics in response to disturbances, climate change, and drought stress, combined with myriad social and policy barriers, have inhibited widespread implementation. Using the forest succession model LANDIS‐II, we investigated the likely impacts of increasing prescribed fire frequency and extent on wildfire severity and forest carbon storage at local and landscape scales. Specifically, we ask how much prescribed fire is required to maintain carbon storage and reduce the severity and extent of wildfires under divergent climate change scenarios? We simulated four prescribed fire scenarios (no prescribed fire, business‐as‐usual, moderate increase, and large increase) in the Siskiyou Mountains of northwest California and southwest Oregon. At the local site scale, prescribed fires lowered the severity of projected wildfires and maintained approximately the same level of ecosystem carbon storage when reapplied at a ~15‐year return interval for 50‐year simulations. Increased frequency and extent of prescribed fire decreased the likelihood of aboveground carbon combustion during wildfire events. However, at the landscape scale, prescribed fire did not decrease the projected severity and extent of wildfire, even when large increases (up to 10× the current levels) of prescribed fire were simulated. Prescribed fire was most effective at reducing wildfire severity under a climate change scenario with increased temperature and precipitation and on sites with north‐facing aspects and slopes greater than 30°. Our findings suggest that placement matters more than frequency and extent to estimate the effects of prescribed fire, and that prescribed fire alone would not be sufficient to reduce the risk of wildfire and promote carbon sequestration at regional scales in the Siskiyou Mountains. To improve feasibility, we propose targeting areas of high concern or value to decrease the risk of high‐severity fire and contribute to meeting climate mitigation and adaptation goals. Our results support strategic and targeted landscape prioritization of fire treatments to reduce wildfire severity and increase the pace and scale of forest restoration in areas of social and ecological importance, highlighting the challenges of using prescribed fire to lower wildfire risk. [ABSTRACT FROM AUTHOR]