High Emission Scenario Research Articles

Atmospheric River Sequences as Indicators of Hydrologic Hazard in Historical Reanalysis and GFDL SPEAR Future Climate Projections

AbstractWhen multiple atmospheric rivers (ARs) occur in rapid succession, the combined effect on the hydrologic system can lead to more flooding and damage than would be expected from the individual events. This temporally compounding risk is a source of growing concern for water managers in California. We present a novel moving average‐based definition of AR “sequences” that identifies the time periods of elevated hydrologic hazard that occur during and after consecutive AR events. This marks the first quantitative evaluation of when temporal compounding is contributing to AR flood risk. We also assess projected changes in sequence frequency, intensity, and duration in California using the Geophysical Fluid Dynamics Laboratory Seamless System for Prediction and EArth system Research (GFDL SPEAR) global coupled model. Sequence frequency increases over time and is fairly uniform across the state under both intermediate (SSP2–4.5) and very high (SSP5–8.5) emissions scenarios, with the largest changes occurring by the end of the century (+0.72 sequences/year in SSP2–4.5, +1.13 sequences/year in SSP5–8.5). Sequence intensity and duration both see increases in the medians and extreme values of their respective distributions relative to the historical baselines. In particular, “super‐sequence” events longer than 60 days are projected to occur 2–3x more frequently and to emerge in places that have never seen them in the historical record. In a world where California precipitation is becoming more variable, our definition of sequences will help identify when and where hydrologic impacts will be most extreme, which can in turn support better management of the state's highly variable water resources and inform future flood mitigation strategies.

Potential future changes in soil carbon dynamics in the Ziwuling Forest, China under different climate change scenarios

Soil carbon (C) cycling processes in terrestrial ecosystems are significantly influenced by global changes, and soil microorganisms play a crucial role in soil organic carbon (SOC) and its feedbacks to climate change. To investigate the potential future changes in soil C dynamics under different scenarios in the Ziwuling Forest region, China, we conducted a soil observation and sampling experiment from April 2021 to July 2022. By utilizing a microbial ecological model (MEND), we aimed to predict the future dynamics of soil C under different scenarios in the area. Our results demonstrate that under the RCP2.6 (Representative Concentration Pathway) scenario, SOC showed a rapid increase, SOC under the RCP2.6 scenario will be significantly higher than those under the RCP4.5 scenario and RCP8.5 scenario in the topsoil and whole soil. Furthermore, the positive correlation between total litter carbon (LC) and SOC under the RCP2.6 scenario highlights the potential role of total litter carbon in driving SOC dynamics. Our study also revealed that the low greenhouse gas (GHG) emission scenario favors the accumulation of SOC in the study area, while the high GHG emission scenario leads to greater soil carbon loss. Overall, these results underscore the importance of considering the impact of climate change, especially global warming, on soil ecosystems in the future. Protecting the soil ecosystem of the Loess Plateau is critical for maintaining soil carbon sinks, preventing soil erosion, and improving and regulating the surrounding environmental climate.

Unique ocean circulation pathways reshape the Indian Ocean oxygen minimum zone with warming

Abstract. The global ocean is losing oxygen with warming. Observations and Earth system model projections, however, suggest that this global ocean deoxygenation does not equate to a simple and systematic expansion of tropical oxygen minimum zones (OMZs). Previous studies have focused on the Pacific Ocean; they showed that the outer OMZ deoxygenates and expands as oxygen supply by advective transport weakens, the OMZ core oxygenates and contracts due to a shift in the composition of the source waters supplied by slow mixing, and in between these two regimes oxygen is redistributed with little effect on OMZ volume. Here, we examine the OMZ response to warming in the Indian Ocean using an ensemble of Earth system model high-emissions scenario experiments from the Coupled Model Intercomparison Project Phase 6. We find a similar expansion–redistribution–contraction response but show that the unique ocean circulation pathways of the Indian Ocean lead to far more prominent OMZ contraction and redistribution regimes than in the Pacific Ocean. As a result, only the outermost volumes (oxygen>180 µmol kg−1) expand. The Indian Ocean experiences a broad oxygenation in the southwest driven by a reduction in waters supplied by the Indonesian Throughflow in favor of high-oxygen waters supplied from the southern Indian Ocean gyre. Models also project a strong localized deoxygenation in the northern Arabian Sea due to the rapid warming and shoaling of marginal sea outflows (Red Sea and Persian Gulf) and increases in local stratification with warming. We extend the existing conceptual framework used to explain the Pacific OMZ response to interpret the response in the Indian Ocean.

Comparative analysis of climate-induced changes in distribution of representative fish species in the Yellow Sea

Climate changes are posing remarkable impacts on marine fish and fisheries. Although many studies have addressed the distributional effects of climate change on single fish species or taxa in recent years, comparative studies focusing on different types of fish are still lacking. In this study, we applied dynamic bioclimate envelop models (DBEM), based on three earth system models, to predict sea surface and bottom temperature, as well as the spatial and temporal distribution of nine representative fishes in the Yellow Sea, contain two habitats, i.e., continental shelf benthopelagic (CBD) and continental shelf pelagic-neritic (CPN) fishes, and two thermophilies, i.e., warm temperate (WT) and warm water (WW) fishes. Under a low emissions scenario (RCP 2.6) and a high emissions scenario (RCP 8.5) between 1970 and 2060, results reveal that: a) CPN fishes show a distinct tendency to move to higher latitudes than CBD fishes, and WW fishes show a significant tendency to migrate more widely to the north than WT fishes; b) The relative abundance of CPN fishes is expected to be higher than that of CBD fishes, while there is no apparent difference in relative abundance between WW fishes and WT fishes. The main reasons for this difference are presumed to be: variance of temperature rise between the sea surface and bottom layers, divergent adaptations of the species, and disparate degrees of anthropogenic influence.

Modelling soil organic carbon dynamics under extreme climate and land use and land cover changes in Western Oromia Regional state, Ethiopia

The combined effects of changes in climate and land use and land cover can lead to a decrease in soil organic carbon, potentially affecting soil fertility and agricultural output. The study aimed to evaluate the dynamics of soil organic carbon under various extreme climate and land use and land cover scenarios. The data on land use types and extreme climate indices between 2015 and 2070 were, respectively, sourced from the IPCC and the European Copernicus Climate Change Service webpages. The 2015 baseline data for soil organic carbon was obtained from the African Soil Information Service's website. Data quality control and model validation were conducted to ensure the reliability of the collected data and the predictive model. A generalized regression model was chosen for its accuracy and reliability in predicting soil organic carbon dynamics under different shared socio-economic pathways such as SSP1-2.6, SSP2-4.5, and SSP5-8.5 scenarios. The study revealed that variations in extreme climate and land use patterns significantly influenced the organic carbon content of the soil. Increased dry days and the conversion of forest and grassland into farmland resulted in a drop in soil organic carbon, while increased wet days and warming temperatures significantly increase it under each scenario. The soil organic carbon content increased by 5.82 and 2.8 g/kg for the SSP1-2.6 and SSP2-4.5 scenarios, respectively, but decreased by 6.90 g/kg under the SSP5-8.5 scenario. Overall, the higher emission scenarios had a significant negative impact on soil organic carbon levels, while the low emission scenarios had a positive impact. Sustainable land management practices are crucial for preserving and managing soil organic carbon levels.

Seasonal temperature and precipitation record breakings in Hungary in a warming world

Climate change is leading to new daily record-breaking values globally. Since there is a clear shift towards the higher temperature values, the ratio of the numbers of new record high temperatures to record lows indicates the acceleration of global warming differently at regional levels—but is there an amplification for precipitation records as well? The main purpose of this regional analysis is to determine how many record highs/lows are broken on a seasonal level, and how large the area affected is, which enables us to assess the potentially large impacts at a local scale. The analysis is based on the statistical characteristics that the number of record breakings decreases exponentially with time for a stationary climate (when natural variability prevails). The assessment focuses on Hungary and considers the past from 1971 and the future from 2021. Results suggest that (1) currently the ratio of the numbers of new record high to record low temperatures is higher in Hungary than globally, particularly for summer and autumn (around 3.5); (2) substantially more new warm records and almost no cold records are expected by the late century (with a ratio of 140–160) following a high emission scenario, particularly in summer, when the impacts of these record breakings are the largest; (3) new precipitation records in the region are much less affected by the anthropogenic activity.

Regional-scale flood impacts on a small mountainous catchment in Thailand under a changing climate

Abstract Extreme rainfall and flooding are common during the summer monsoon season in Thailand. In this study, we utilized Robust Empirical Quantile Mapping (RQUANT) to correct the bias in precipitation, and total runoff data obtained from the latest Couple Model Intercomparison Project phase 6 (CMIP6) for the upper Lam Takong river basin. Five different methods were employed to estimate the river discharge and four estimations based on Budyko functions. Our analysis revealed that the ‘Total runoff’ method yielded the most accurate representation of the observed discharge. Impacts of change in land use are examined in terms of compound roughness. The Multi-Model Ensemble (MME) precipitation under medium-emission (SSP2-4.5) and high-emission (SSP5-8.5) scenarios is projected to increase by 5.74 and 10.91%, respectively. Correspondingly, the discharges are expected to increase by 4.57 and 11.05% for the far-future periods. In general, the Flo-2D model satisfactorily simulated the water level in the main channel but it underestimated small inundation depth (<0.5 m) across the floodplain. Comparing inundation maps among different scenarios and timelines, changes in the inundation area were relatively small (0.05%), especially when compared to changes in floodplain storage (6.85%) due to the mountainous nature of the river basin.

Historical Evolution and Future Trends of Precipitation Based on Integrated Datasets and Model Simulations of Arid Central Asia

Earth system models (ESMs) are important tools for assessing the historical characteristics and predicting the future characteristics of precipitation, yet the quantitative understanding of how these land–atmospheric coupling models perform in simulating precipitation characteristics remains limited. This study conducts a comprehensive evaluation of precipitation changes simulated by 43 ESMs in CMIP5 and 32 ESMs in CMIP6 in Arid Central Asia (ALL) and its two sub-regions for 1959–2005 with reference to Climate Research Unit (CRU) data, and predicts precipitation changes for 2054–2100. Our analyses suggest the following: (a) no single model consistently outperformed the others in all aspects of simulated precipitation variability (annual averages, long-term trends, and climatological monthly patterns); (b) the CMIP5 and CMIP6 model simulations tended to overestimate average annual precipitation for most of the ALL region, especially in the Xinjiang Uygur Autonomous Region of China (XJ); (c) most model simulations projected a stronger increasing trend in average annual precipitation; (d) although all the model simulations reasonably captured the climatological monthly precipitation, there was an underestimation; (e) compared to CMIP5, most CMIP6 model simulations exhibited an enhanced capacity to simulate precipitation across all aspects, although discrepancies persisted in individual sub-regions; (f) it was confirmed that the multi-model ensemble mean (MME) provides a more accurate representation of the three aspects of precipitation compared to the majority of single-model simulations. Lastly, the values of precipitation predicted by the more efficient models across the ALL region and its sub-regions under the different scenarios showed an increasing trend in most seasons. Notably, the strongest increasing trend in precipitation was seen under the high-emission scenarios.

Increase in ocean-onto-land droughts and their drivers under anthropogenic climate change

Ocean-onto-land droughts (OTLDs)—i.e., droughts originating over the oceans and migrating onto land—are a recently identified phenomenon with severe natural and human impacts. However, the influence of anthropogenic emissions on past and future changes in OTLDs and their underlying mechanisms remain unclear. Here, using precipitation-minus-evaporation deficits to identify global OTLDs, we find OTLDs have intensified due to anthropogenic climate change during the past 60 years. Under a future high-emissions scenario, the OTLDs would become more frequent (+39.68%), persistent (+54.25%), widespread (+448.92%), and severe (+612.78%) globally. Intensified OTLDs are associated with reduced moisture transport driven by subtropical anticyclones in the northern hemisphere and complex circulation patterns in the southern hemisphere. The reduction in moisture transport during OTLDs is mainly caused by the atmospheric thermodynamic responses to human-induced global warming. Our results underscore the importance of improving understanding of this type of drought and adopting climate mitigation measures.

Projected increase in summer heat-dome-like stationary waves over Northwestern North America

Heat-dome-like stationary waves often lead to extreme heat events, such as the unprecedented heatwave in Northwestern North America during the summer of 2021. However, future changes in summer stationary waves over Northwestern North America and the underlying driving factors remain unclear. Here, we investigate the projected changes in the anticyclonic stationary wave circulation over Northwestern North America using data from the Coupled Model Intercomparison Project Phase 6 and diagnose the circulation changes using a stationary wave model. Our findings reveal a significant 95% increase in the summer stationary wave amplitude over Northwestern North America under the high-emission scenario in 2080–2099 relative to 1995–2014. The response is mainly driven by the diabatic heating changes over the tropical Pacific which induce a Rossby wave source in the northeastern tropical Pacific, and further supported by a northward expanded waveguide in North America, both enhancing wave activity flux into the Northwestern North America. The heat-dome-like stationary wave anomaly is expected to heighten the heatwave risk over the region.

Climate change alters global invasion vulnerability among ecoregions

AbstractAimWe assess climate similarity among global freshwater and terrestrial ecoregions under historical and future climate scenarios to determine where climate change will impact the climate filter of invasion process.LocationGlobal.MethodsWe used the Climatch algorithm to conduct a climate‐match analysis to quantify the climate similarity between freshwater and terrestrial ecoregions of the world. Climate match was modelled between all freshwater and terrestrial ecoregions. The analysis was conducted under historical climates and projected climates of 2081–2100 (2090) under three shared socioeconomic pathways SSP2‐4.5, SSP3‐7.0, SSP5‐8.5. Climate matches of each ecoregion were presented as mean climate match to all other ecoregions of the same set. Friedman's non‐parametric rank sum two‐way analysis of variance with repeated measures was used to examine differences in mean climate match between climate scenarios.ResultsMean climate match of ecoregions was projected to increase significantly with small effect sizes for freshwater ecoregions (recipients: 0.132; sources: 0.105), and moderate and small effect sizes for terrestrial ecoregions (recipients: 0.330; sources: 0.259). Climate change was predicted to increase mean climate match in North America and Eurasia, particularly in the Arctic by 2090 under each SSP. Ecoregions in central Africa and South America were predicted to have reduced mean climate match. Ecoregions within larger countries (e.g. Australia, Canada, USA) showed variation in mean climate match.Main ConclusionClimate change projections of bioclimatic predictors of species invasions were shown to increase in homogeneity under higher emissions scenarios. Furthermore, we demonstrate how climate change will provide opportunities for invasive species transported among ecoregions to survive under new conditions and identify where the climate filter of the invasion process will be most affected. Findings can be used to inform conservation actions for mitigating the impacts of introduced species by identifying potential risky source regions of future freshwater and terrestrial invasions under climate change.

Drought characteristics projections based on CMIP6 climate change scenarios in Syria

Study regionSyria Study focusThis study delves into predicting drought characteristics in Syria, focusing on their duration, frequency, and intensity. It utilizes a set of 13 models sourced from the latest CMIP6 dataset, encompassing two distinct SSP scenarios. To evaluate how well CMIP6 represents drought attributes in Syria, the research conducts a comparison with observed monthly climate data from CRU TS v4.06 and ERA 5, as well as the CMIP6 model ensemble outputs for the reference period (1970–2000). New hydrological insights for the regionThis study provides new hydrological insights for Syria. It reveals robust projections of increasing drought severity, frequency, and duration, particularly in the north and northeast arid and semi-arid regions, even under aggressive climate mitigation scenarios. Additionally, the study highlights that higher emissions scenarios are associated with more prolonged and intense drought events, potentially impacting even less vulnerable areas. These findings emphasize the urgent need for drought adaptation and mitigation measures, as well as improved water resource planning, in order to address the changing hydrological landscape of the region. Furthermore, it underscores the long-lasting effects of drought on ecosystem recovery, which may span several decades.

Impacts of Climate Change on Vegetation in Kenya: Future Projections and Implications for Protected Areas

Climate change will cause substantial vegetation shifts across the world. Africa may face varying dynamics such as tree decline, savannization, and woody encroachment due to rising temperatures and rainfall changes. This study examines the potential effects of climate change on Kenyan vegetation and vegetation shifts for 2050 and 2100, employing a statistical model to predict vegetation state as driven by environmental variables, including temperature, soil moisture, livestock density, and topography. We evaluate the model by hindcasting it from 2020 to 2000 and then project future vegetation states for 2050 and 2100 under SSP 2–4.5 and SSP 5–8.5. In response to moderate emissions, a notable increase in arid-associated shrubland vegetation (53–58%) is forecasted, leading to the expansion of drylands at the expense of savannas, grasslands, and forests. Under high-emission scenarios, savannas are forecasted to expand (52–65%) at the expense of forested areas. Overall, dense forest cover declines across scenarios, affecting protected areas by promoting increased savanna cover and reducing forest area (40% to 50%). These projected shifts in major vegetation types would likely alter ecosystem functioning and associated services, impacting pastoralists and wildlife and raising biodiversity concerns. Protected areas in Kenya could lose 50% of their forests, highlighting the urgency of climate change mitigation. These findings offer a crucial foundation for future research and action on Kenya’s vegetation.

Anthropogenic climate change drives non-stationary phytoplankton internal variability

Abstract. Earth system models suggest that anthropogenic climate change will influence marine phytoplankton over the coming century with light-limited regions becoming more productive and nutrient-limited regions less productive. Anthropogenic climate change can influence not only the mean state but also the internal variability around the mean state, yet little is known about how internal variability in marine phytoplankton will change with time. Here, we quantify the influence of anthropogenic climate change on internal variability in marine phytoplankton biomass from 1920 to 2100 using the Community Earth System Model 1 Large Ensemble (CESM1-LE). We find a significant decrease in the internal variability of global phytoplankton carbon biomass under a high emission (RCP8.5) scenario and heterogeneous regional trends. Decreasing internal variability in biomass is most apparent in the subpolar North Atlantic and North Pacific. In these high-latitude regions, bottom-up controls (e.g., nutrient supply, temperature) influence changes in biomass internal variability. In the biogeochemically critical regions of the Southern Ocean and the equatorial Pacific, bottom-up controls (e.g., light, nutrients) and top-down controls (e.g., grazer biomass) affect changes in phytoplankton carbon internal variability, respectively. Our results suggest that climate mitigation and adaptation efforts that account for marine phytoplankton changes (e.g., fisheries, marine carbon cycling) should also consider changes in phytoplankton internal variability driven by anthropogenic warming, particularly on regional scales.

Drought trends projection under future climate change scenarios for Iran region.

The study highlights the potential characteristics of droughts under future climate change scenarios. For this purpose, the changes in Standardized Precipitation Evapotranspiration Index (SPEI) under the A1B, A2, and B1 climate change scenarios in Iran were assessed. The daily weather data of 30 synoptic stations from 1992 to 2010 were analyzed. The HadCM3 statistical model in the LARS-WG was used to predict the future weather conditions between 2011 and 2112, for three 34-year periods; 2011-2045, 2046-2079, and 2080-2112. In regard to the findings, the upward trend of the potential evapotranspiration in parallel with the downward trend of the precipitation in the next 102 years in three scenarios to the base timescale was transparent. The frequency of the SPEI in the base month indicated that 17.02% of the studied months faced the drought. Considering the scenarios of climate change for three 34-year periods (i.e., 2011-2045, 2046-2079, and 2080-2112) the average percentages of potential drought occurrences for all the stations in the next three periods will be 8.89, 16.58, and 27.27 respectively under the B1 scenario. While the predicted values under the A1B scenario are 7.63, 12.66, and 35.08%respectively. The relevant findings under the A2 scenario are 6.73, 10.16, 40.8%. As a consequence, water shortage would be more serious in the third period of study under all three scenarios. The percentage of drought occurrence in the future years under the A2, B1, and A1B will be 19.23%, 17.74%, and 18.84%, respectively which confirms the worst condition under the A2 scenario. For all stations, the number of months with moderate drought was substantially more than severe and extreme droughts. Considering the A2 scenario as a high emission scenario, the analysis of SPEI frequency illustrated that the proportion of dry periods in regions with humid and cool climate is more than hot and warm climates; however, the duration of dry periods in warmer climates is longer than colder climates. Moreover, the temporal distribution of precipitation and potential evapotranspiration indicated that in a large number of stations, there is a significant difference between them in the middle months of the year, which justifies the importance of prudent water management in warm months.

Limiting global warming to 2 °C benefits building climate resilience in rice-wheat systems in India through crop calendar management

CONTEXTRice-wheat rotation system (RWS) is the most important food production system in South Asia and contributes approximately 50% of the total food consumed in India. Building climate resilience of RWS in the context of global warming is critical to sustainably feeding the ever-increasing population in India. Prior research has shown a large potential for climate change adaptation in rice and wheat production through cropping calendar adjustment, but the climate resilience of rice-wheat systems remains elusive. OBJECTIVEThe study aims to project coupled changes in the growing seasons of rice and wheat in RWS under global warming, and evaluate climate resilience of RWS productivity in India through crop calendar adjustment. METHODSWe combined an improved Environmental Policy Integrated Climate model with satellite remote sensing data to investigate the coupling of rice and wheat growing seasons in RWS in India. Then, we shifted crop calendars in RWS to simulate optimal planting dates and potential yield changes of rice and wheat under contrasting global warming scenarios. RESULTS AND CONCLUSIONSWe show that farmers will face a yield trade-off between monsoon rice and dry-season wheat under high greenhouse gas emission scenarios (4 °C warming by the end of the century) in the Indo-Gangetic Plains (IGP) due to a tighter coupling of crop growing seasons in RWS. Early planting for both monsoon rice and dry-season wheat is recommended in the current climate, but the strategy does not apply to future climate change scenarios in the IGP. Limiting global warming below 2 °C by the end of the century is likely to improve RWS productivity by 14% in irrigated systems and 21% in rainfed systems, and keep sufficient maneuvering space for resilient planting strategies in the future. SIGNIFICANCEOur analysis emphasizes that failure to fulfill the pledges of the Paris Agreement will result in not only higher crop damage but also more challenging climate adaptation planning in RWS in India.

MIROC6 Large Ensemble (MIROC6-LE): experimental design and initial analyses

Abstract. Single model initial-condition large ensembles (LEs) are a useful approach to understand the roles of forced responses and internal variability in historical and future climate change. Here, we produce one of the largest ensembles thus far using the MIROC6 coupled atmosphere–ocean global climate model (MIROC6-LE). The total experimental period of MIROC6-LE is longer than 76 000 years. MIROC6-LE consists of a long preindustrial control run, 50-member historical simulations, 8 single forcing historical experiments with 10 or 50 members, 5 future scenario experiments with 50 members and 3 single forcing future experiments with 50 members. Here, we describe the experimental design. The output data of most of the experiments are freely available to the public. This dataset would be useful to a wide range of research communities. We also demonstrate some examples of initial analyses. Specifically, we confirm that the linear additivity of the forcing-response relationship holds for the 1850–2020 trends of the annual mean values and extreme indices of surface air temperature and precipitation by analyzing historical fully forced runs and the sum of single forced historical runs. To isolate historical anthropogenic signals of annual mean and extreme temperature for 2000–2020 relative to 1850–1900, ensemble sizes of 4 and 15, respectively, are sufficient in most of the world. Historical anthropogenic signals of annual mean and extreme precipitation are significant with the 50-member ensembles in 76 % and 69 % of the world, respectively. Fourteen members are sufficient to examine differences in changes in annual mean values and extreme indices of temperature and precipitation between the shared socioeconomic pathways (ssp), ssp585 and ssp126, in most of the world. Ensembles larger than 50 members are desirable for investigations of differences in annual mean and extreme precipitation changes between ssp126 and ssp119. Historical and future changes in internal variability, represented by departures from the ensemble mean, are analyzed with a focus on the El Niño/Southern Oscillation (ENSO) and global annual mean temperature and precipitation. An ensemble size of 31 is large enough to detect ENSO intensification from preindustrial conditions to 1951–2000, from 1951–2000 to 2051–2100 in all future experiments, and from low- to high-emission future scenario experiments. The single forcing historical experiments with 27 members can isolate ENSO intensification due to anthropogenic greenhouse gas and aerosol forcings. Future changes in the global mean temperature variability are discernible with 23 members under all future experiments, while 50 members are not sufficient for detecting changes in the global mean precipitation variability in ssp119 and ssp126. We also confirm that these temperature and precipitation variabilities are not precisely analyzed when detrended anomalies from the long-term averages are used due to interannual climate responses to the historical natural forcing, which highlights the importance of large ensembles for assessing internal variability.

Liquid phase methanol synthesis by CO2 hydrogenation over Cu-Zn/Z catalysts: Influence of Cd promotion

BackgroundThe current scenario of high CO2 emissions, which is causing global warming and climate change, one of the greatest challenges faced by the global community. One of the most promising ways to recycle CO2 and thus mitigate its emission into the natural environment is the catalytic conversion of CO2 into valuable products such as methanol, hydrocarbons, dimethyl ether (DME), formaldehyde, syngas, alcohols and urea. MethodZeolite supported Cu-Zn bimetallic (Cu-Zn/Z) catalysts were synthesized by co-precipitation method. The synthesized catalysts were doped with different concentration of Cd to investigate the promoting role of Cd. To investigate the physicochemical profile of the calcined Cu-Zn/Z nano-catalysts, various analytical techniques were used. Significant findingsThermal stability of zeolite support was carried out using Thermogravimetric analysis (TGA). TGA data exhibited higher thermal stability of the zeolite support. XRD findings revealed highly dispersed Cd promoted Cu-Zn oxides on the surface of the zeolite support. Field Emission Scanning Electron Microscopy (FESEM) was used to investigate morphology, which indicated the nano size of synthesized catalysts with uniform distribution of metal oxides. Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) detected bulk composition of each metal. BET surface studies revealed the mesoporous nature of Cd promoted Cu-Zn/Z catalysts. X-ray Photoelectron Spectroscopy (XPS) revealed the surface chemistry of Cd promoted Cu-Zn/Z catalysts. Activity data showed the active profile of Cd promoted Cu-Zn/Z catalysts for CO2 hydrogenation to methanol by accelerating the methanol synthesis rate from 73 to 157 g.meth/kg.cat.h. Structure-activity studies identified metal-support interactions and Cu stability as the main factors governing the three-phase methanol synthesis rate from CO2 hydrogenation. The importance of Cd promotion was further demonstrated by the fact that activity profile revealed better performance of the current catalysts with recently reported data in the literature.

Maximizing photovoltaic potential and minimizing costs in a future warmer climate: The role of atmospheric aerosols and greenhouse gas emissions

Climate change in the upcoming decades will affect solar resources and impact photovoltaic (PV) energy generation, which is key for the global energy transition. The climate-change associated costs for future solar plants need to be assessed, considering different climate futures and PV technologies. Here we show PV power potential increases up to 6% (12% at the end of century) in Europe, eastern America, and south Asia, while reductions predominate in the rest of the world. While temperature and radiation changes dominate the PV changes, atmospheric aerosols also play an important role in future PV production, which has not been thoroughly evaluated before. In future high-emission scenarios, the best outcomes are achieved with thin-film modules that are more resilient to a warmer climate, highlighting the importance of improving thermal management in market-dominant silicon solar cells. In a future low-emissions scenario, the climate impacts on PV and the associated costs are the lowest, potentially saving up to 12 billion US$/year.

Rapid Acceleration of Dangerous Compound Heatwaves and Their Impacts in a Warmer China

AbstractThis work investigates the possible future changes and impacts in spatiotemporal variation and regional features of multivariate compound heatwaves (CHWs) in China using the latest Universal Thermal Climate Index from the Coupled Model Intercomparison Project Phase 6 simulations (CMIP6). Results indicate both strong CHWs and extremely threatening CHWs in China are projected to increase substantially in both frequency and spatial extent under different future climate scenarios while with discernible regional disparities. The more severe global warming is, and the greater the extremity of the heatwave events is, the faster the increase in CHWs is. These findings are derived from the CMIP6 projections calibrated using the robust empirical quantiles method. Climate change causes more areas and people to be exposed to CHWs. Notably, the population exposure to dangerous CHWs will increase significantly in northwest China and will appear in northeast China after the mid‐21st century under the high emission scenario.