Search

Extreme wet-bulb temperatures (Tw) are often used as indicators of heat stress. However, humid heat extremes are fundamentally compound events, and a given Tw can be generated by various combinations of temperature and humidity. Differentiating between extreme humid heat driven by temperature versus humidity is essential to identifying these extremes’ physical drivers and preparing for their distinct impacts. Here we explore the variety of combinations of temperature and humidity contributing to humid heat experienced across the globe. In addition to using traditional metrics, we derive a novel thermodynamic state variable named “stickiness.” Analogous to the oceanographic variable “spice” (which quantifies the relative contributions of temperature and salinity to a given water density), stickiness quantifies the relative contributions of temperature and specific humidity to a given Tw. Consistent across metrics, we find that high magnitudes of Tw tend to occur in the presence of anomalously high moisture, with temperature anomalies of secondary importance. This widespread humidity dependence is consistent with the nonlinear relationship between temperature and specific humidity as prescribed by the Clausius–Clapeyron relationship. Nonetheless, there is a range of stickiness observed at moderate-to-high Tw thresholds. Stickiness allows a more objective evaluation of spatial and temporal variability in the temperature versus humidity dependence of humid heat than traditional variables. In regions with high temporal variability in stickiness, predictive skill for humid heat-related impacts may improve by considering fluctuations in atmospheric humidity in addition to dry-bulb temperature.

This study assessed smallholder farmers’ vulnerability to climate extremes in west and southwest Showa zones, central Ethiopia. The study used 1981–2020 rainfall and temperature data obtained from the Ethiopian Meteorology Institute and employed RClimDex1 for data quality control and extreme climate indices analysis. The selected ten (10) major components of Livelihood Vulnerability Index (LV I) were used to assess farmers’ vulnerability, categorized into exposure, sensitivity, and adaptive capacity based on the livelihood vulnerability indicator intergovernmental panel for climate change (LVI-IPCC) framework. Primary data gathered through household surveys conducted across 626 selected peasant associations representing different agro ecological zones (lowland, midland, and highland). The primary data analysis performed via statistical package for social sciences (IBM SPSS) Statistics Version 26 and R software. The study finding indicated that lowland agroecology (0.47) is more vulnerable to climate extremes than highlands (0.38) and midlands (0.40) agro-ecologies In terms of smallholder farmers’ sensitivity to extreme climate events, lowland agro-ecology suggested a higher sensitivity index than the other two ecologies. The smallholder farmers’ sensitivity to extreme climate events was 0.70, 0.57, and 0.67 LVI values on lowland, midland, and highland agro-ecosystems, respectively. Midland agroecology has strong adaptive capacity (0.560) and is the least vulnerable. In lowland agroecology, smallholder farmers are more vulnerable to extreme weather because of their limited adaptive capacity and higher exposure. The study’s findings will guide policymakers in addressing the negative effects of climate extreme indices on smallholder farmers. Providing improved seeds, irrigation, credit access, and real-time weather information updates can reduce vulnerability in lowland areas. [ABSTRACT FROM AUTHOR]

Complexity of climate variability and application of pesticides on rice production in Nigeria was investigated. A multi-stage sampling procedure using a structured questionnaire was utilized to sample 401 rice growers. Data for the study were gathered from primary and secondary sources and analyzed using descriptive statistics, the local average treatment effect (LATE), the beta regression model, principal component analysis (PCA), and the autoregressive distributed lag (ARDL) model. The rice farmers were found to be of fruitful age (56 years), male (85%), educated (mean = 12.0), and experienced (18 years). The majority of the rice farmers (89.8%) were conversant with climate change variations, and (50.4%), had a high degree of pesticide use. Climate variables such as temperature, rainfall, number of wet days, evaporation, and sunshine hours were discovered to have both beneficial and adverse significant effects on rice productivity. The use and application of pesticides on rice field increased yield by 987.01% and 710.6% with a negative decrease of 247%. Age, gender, access to credit, education level and climate events were significant determinants of pesticide usage and application among rice farmers. Increased crop failure (0.703), increased soil salinity and acidity (0.700), decreased yield (0.711) and increased insect/pest infestations (0.670) were noted as major perceived consequences of variability in climate and pesticide use. Rice growers were recommended to seek for early climate signals/forecast before embarking on rice cultivation and to adhere strictly to specified instructions regarding pesticide application. [ABSTRACT FROM AUTHOR]

There is an urgent need for information on the Earth's climate beyond the limited history provided in the instrumental record. Paleoclimate information provides a baseline for understanding natural climate variability and how human activities have altered the climate. Paleoclimate reconstructions also allow us to estimate the potential impacts of climate change on multiple aspects of the climate system. Over the past three decades, paleoclimatologists have made great advances in using climate proxies, natural archives of climate conditions, to better understand climates of the past. Here, we categorize the main types of advancements made over recent decades, which include the discovery of new proxies and new measurements from existing proxies, the reconstruction of novel components of the climate system, the geographical expansion of paleoclimate records, and the integration of multiple proxies and models. We provide examples of published research in each category from across the field of paleoclimatology, and we end with a summary of remaining knowledge gaps and emerging questions that will require continued paleoclimate research progress in the future. [ABSTRACT FROM AUTHOR]

Environmental assessment and management of dams are essential for understanding and mitigating their impact on downstream vegetation in arid and semi-arid regions. These regions pose challenges due to water scarcity and extreme climatic conditions. This study uses remote sensing technology to investigate the complex relationships between downstream vegetation changes before and after dam construction and various environmental factors, including land surface temperature, soil moisture, soil salinity, groundwater, runoff water, temperature, and precipitation. This study is notable for its comprehensive parameters and methods, providing unique insight into the direct and indirect impacts of dam construction on vegetation dynamics across diverse climatic regions. The examination encompasses four case studies, including Hali and Baish in Saudi Arabia and Lakes Argyle and Julius in Australia. This analysis utilizes satellite imagery and reanalyzed data, which allow consideration of a long time scale without any restrictions. A moderated mediation analysis explores the direct and indirect associations between downstream flows, environmental factors, and vegetation. Additionally, factor analysis using Principal Component Analysis (PCA) and Two-Step Clustering analysis is utilized to gain deeper insights into the underlying correlations and groupings within the dataset. The research findings highlight the significant roles of runoff, groundwater, soil salinity, and other environmental factors in influencing vegetation before and after dam construction in arid and semi-arid regions. Before dam construction in Hali and Baish, soil salinity, precipitation, and groundwater were key factors for vegetation, with runoff directly affecting arid areas. After construction, soil salinity and groundwater remained crucial, but runoff's direct impact ceased. In semi-arid regions like Lake Argyle and Julius, soil moisture, soil salinity, precipitation, and groundwater remained important, with runoff affecting vegetation cover. The study emphasizes the need to consider these factors, along with the use of remote sensing technology, in ecological and land management studies, noting that factors influencing vegetation dynamics changed significantly before and after dam construction.Highlights: Utilizing multiple satellite observations and reanalyzed datasets, we aim to overcome the limitations of insufficient ground measurements. These combined factors used in this study collectively underscore the contrasting outcomes in runoff's impact on NDVI. Before the dam construction, runoff influenced arid vegetation; post-construction, impact decreased. Before and after dam construction, factors influencing vegetation dynamics shifted significantly. [ABSTRACT FROM AUTHOR]

This study examines the trends and interannual variability of extreme precipitation in Antarctica, using six decades (1963–2023) of daily precipitation data from Russia's Novolazarevskaya Station in East Antarctica. The results reveal declining trends in both the annual number of extreme precipitation days and the total amount of extreme precipitation, as well as a decreasing ratio of extreme to total annual precipitation. These trends are linked to changes in northward water vapor flux and enhanced downward atmospheric motion. The synoptic pattern driving extreme precipitation events is characterized by a dipole of negative and positive height anomalies to the west and east of the station, respectively, which directs southward water vapor flux into the region. Interannual variability in extreme precipitation days shows a significant correlation with the Niño 3.4 index during the austral winter semester (May–October). This relationship, weak before 1992, strengthened significantly afterward due to shifting wave patterns induced by tropical Pacific sea surface temperature anomalies. These findings shed light on how large-scale atmospheric circulation and tropical-extratropical teleconnections shape Antarctic precipitation patterns, with potential implications for ice sheet stability and regional climate variability. [ABSTRACT FROM AUTHOR]

The variability of daytime–nighttime compound heat waves (CHWs) is a highly concerning issue due to severe impacts on human and natural systems. Although several studies surveyed physical processes for the CHW occurrence, its interannual variability and associated mechanisms have not been well understood. Focusing on CHWs in the Yangtze River valley (YRV, a hotspot across China), this paper indicates an emergence of enlarged interannual variability after entering into the twenty-first century, before which the interannual variability was quite small. The possible mechanism underlying the high interannual variability is further explored in terms of atmospheric and oceanic backgrounds. The results show that the atmospheric background associated with higher-than-normal CHWs over the YRV features anticyclonic circulation anomalies tilting southeastward from the north of the YRV in the upper troposphere to the western Pacific in the lower troposphere. Accordingly, the upper-tropospheric easterly and lower-tropospheric southwesterly anomalies dominate the YRV, causing anomalous subsidence and increased humidity in situ, respectively, which benefit the increase in CHWs. The tripole (positive–negative–positive) sea surface temperature (SST) anomalies in the North Atlantic (NA) and the positive SST anomalies in the Maritime Continent (MC) also play roles in increasing the YRV CHWs by influencing the above atmospheric circulations. The NA tripole SST anomalies tend to affect the upper- and midtropospheric anticyclonic anomalies through the eastward-propagating wave train across Eurasia. The warming of the MC SSTs can impact the lower-tropospheric anticyclonic anomaly over the western Pacific via local meridional circulation. The opposite situations are applicable for decreased CHWs over the YRV. Significance Statement: Daytime–nighttime compound heat waves (CHWs) refer to persistent processes with abnormally high temperatures occurring both in daytime and nighttime. Compared with heat waves (HWs) occurring only at daytime or nighttime, the CHWs exert more severe damage to natural ecosystems and human society. Thus, understanding the physical mechanisms of CHWs is urgently needed. This study examines the interannual variability of Yangtze River valley (YRV) CHWs and finds that it exhibits a pronounced enlargement after 2000. During this period, an anomalous anticyclone tilting southeastward from the north of the YRV in the upper level to the western Pacific in the lower level is a favorable atmospheric circulation background for the increase in CHWs over the YRV, and vice versa. Sea surface temperatures (SSTs) in the North Atlantic (NA) and the Maritime Continent (MC) also play important roles. The positive–negative–positive SST anomalies in the NA and the warming SSTs in the MC tend to increase the YRV CHWs, through their influences on CHW-related atmospheric circulations in the upper troposphere and lower troposphere, respectively. These findings are expected to deepen our understanding of CHW variability, which are of great importance for disaster prevention and mitigation. [ABSTRACT FROM AUTHOR]

Climate change simulations generally indicate the strengthening of El Niño–Southern Oscillation (ENSO) sea surface temperature (SST) variability through the twenty-first century, yet a robust physical mechanism explaining this change across different models is still lacking, and the projections for ENSO amplitude exhibit a large spread. Most commonly, changes in the background state of the tropical Pacific are invoked to explain these changes of ENSO. Here, we show that changes in the structure of wind stress anomalies associated with ENSO are potentially as important as these background state changes. Specifically, changes in the magnitude, meridional width, and zonal structure of wind stress anomalies can explain approximately 53% of the intermodel variance in the projected change of ENSO magnitude through the twenty-first century as well as 43% in ENSO periodicity changes. Among these changes in the wind structure, the meridional widening of wind anomalies plays the most important role. To demonstrate that these changes are indeed critical, we develop a hybrid model of ENSO based on the Community Earth System Model, version 2, which incorporates a dynamical ocean coupled to a simplified statistical atmosphere within the tropical Pacific. In the absence of external forcing and corresponding mean-state changes, the imposed changes in wind stress anomalies in this hybrid model result in an increase of ENSO amplitudes of nearly 10% along the equator. Our results are also theoretically supported by a recharge-oscillator model that incorporates the meridional wind structure. Thus, changes in the structure of wind stress anomalies, together with changes in the mean state, likely play a critical role in the projected strengthening of ENSO. [ABSTRACT FROM AUTHOR]

Atmospheric models forced with observed sea surface temperatures (SSTs) suggest a trend toward a more-stabilizing cloud feedback in recent decades, partly due to the surface cooling trend in the eastern Pacific (EP) and the warming trend in the western Pacific (WP). Here, we show model evidence that the low-cloud feedback has contributions from both forced and unforced feedback components and that its time variation arises in large part through changes in the relative importance of the two over time, rather than through variations in forced or unforced feedbacks themselves. Initial-condition large ensembles (LEs) suggest that the SST patterns are dominated by unforced variations for 30-yr windows ending prior to the 1980s. In general, unforced SSTs are representative of an ENSO-like pattern, which corresponds to weak low-level stability in the tropics and less-stabilizing low-cloud feedback. Since the 1980s, the forced signals have become stronger, outweighing the unforced signals for the 30-yr windows ending after the 2010s. Forced SSTs are characterized by relatively uniform warming with an enhancement in the WP, corresponding to a more-stabilizing low-cloud feedback in most cases. The time-evolving SST pattern due to this increasing importance of forced signals is the dominant contributor to the recent stabilizing shift of low-cloud feedback in the LEs. Using single-forcing LEs, we further find that if only greenhouse gases evolve with time, the transition to the domination of forced signals occurs 10–20 years earlier compared to the LEs with full forcings, which can be understood through the compensating effect between aerosols and greenhouse gases. [ABSTRACT FROM AUTHOR]

During early boreal winter, the extratropical atmospheric circulation is influenced by Rossby waves propagating from the Indian Ocean toward the North Atlantic–European (NAE) regions, resulting in a North Atlantic Oscillation (NAO)-like pattern. The mechanisms driving these teleconnections are not well understood and are crucial for improving model skills. This study investigates these mechanisms using the ERA5 dataset and tests the predictive capabilities of the ECMWF SEAS5, exploring potential reasons for a weak model response. Linear regression methods are employed to examine the extratropical links with the Indian Ocean dipole (IOD), both in isolation and in combination with El Niño–Southern Oscillation (ENSO). Our findings demonstrate a connection between October IOD sea surface temperature anomalies and December Indian Ocean precipitation patterns. Furthermore, a correlation between the October IOD and December NAO time series suggests a link between the IOD and NAE circulation. The early winter European response to a positive IOD is characterized by a north–south precipitation dipole and a large positive surface air temperature anomaly. Positive feedback from transient eddy forcing reinforces the wavenumber-3-like propagation across extratropical regions, with ENSO playing a minor role compared to the IOD. This phenomenon is particularly evident in regions such as the North Pacific and North Atlantic, where wave energy propagation is intensified. Although SEAS5 replicates the NAO response, its magnitude is significantly weaker. The model struggles to simulate the delayed rainfall dipole response to the IOD accurately and shows structural discrepancies compared to reanalysis data. [ABSTRACT FROM AUTHOR]

Smallholder vegetable farmers grow diverse crops for family use and surplus sales. These farming activities contribute to enhancing local food security and the economy, but the farmers face challenges like limited resources and climate vulnerability. These smallholder farmers are more susceptible to climate variability and therefore need effective adaptation strategies to mitigate the challenges. This study sought to determine the factors that influence the choice and level of adaptation strategies among smallholder vegetable farmers in KwaZulu Natal Province. Primary data utilized in this study were obtained from 200 participants that were selected through random sampling. The descriptive results indicated that the majority of the farmers experienced climate variability and employed carbon and water-smart agricultural practices. The study employed the Multivariate Probit Model and Count Data Model/GLM Correlation Test to analyze the adaptation strategies and the level of their implementation by the selected vegetable farmers. The first hurdle of the probit model results showed that education level and land size positively and significantly influence smallholder farmers' adaptation strategies, while marital status, household size, income source, soil type, membership of the association, and supply chain involvement had a significant and negative effect on adoption of adaptation strategies. The results from the second hurdle showed that household size, the total size of land used for vegetable production, sandy, silt, and loam soil had a significant and negative effect on the level of adaptation strategy used, whilst the total size of land owned had a positive and significant impact on the level of adaptation strategy used by the smallholder vegetable farmers. The study concludes that education level and total land size are associated with improved farmers' climate variability adaptative capacity. The vegetable farmers' ability to adapt to climate variability challenges was negatively influenced by factors like marital status, household size, and soil type negatively impacted these strategies. The study recommends that the government considerably supports the Climate Smart Agriculture initiatives, such as alternatives like hot houses, training, credit access, and sustainable practices to enhance farmers' resilience and national food security. These may include but are not limited to alternatives like hot houses, as well as addressing barriers through training, credit access, and sustainable practices to enhance farmers' resilience and national food security. [ABSTRACT FROM AUTHOR]

Feed availability and accessibility are two of the main challenges for Benin livestock systems, which are currently subject to environmental stress and changing climatic conditions. The aim of this study was to assess the main fodder resources used by livestock in Benin by estimating fodder supply and demand for livestock in Benin's agroecological zones (AEZs) and establishing a fodder balance. A total of 314 agrofarmers were surveyed using simple random sampling. Data were collected through discussions with agropastoralists, structured questionnaires, secondary data and observations. The survey in the eight AEZs of Benin revealed that maize residues are the main crop residues used in livestock feed (53.14%), followed by sorghum residues (8.41%), millet (5.91%), soya (8.1%) and rice (5). It also found that natural grazing areas are the main fodder resources used in Benin, with a dry matter contribution of 74% compared with 26% for crop residues. The study of the availability of fodder resources revealed a positive fodder balance for dry matter (DM) in each agroecological zone, but a negative balance in all AEZs for metabolizable energy (ME) and digestible crude protein (DCP). Thus, with an average annual availability of almost 3.15 million tons of DM across all Benin AEZs, zones 2, 3 and 5 had the highest DM availability rates, while AEZs 1, 7 and 8 had the lowest DM availability. To alleviate this problem of food shortages for livestock, we suggest interventions to improve the productivity of grazing areas; The introduction of fodder crops with the emphasis on legumes and efficient use of available fodder resources, such as the treatment of livestock feed (treatment of poor fodder with urea is one example). [ABSTRACT FROM AUTHOR]

The Qin and Western Han dynasties (221 BCE to 24 CE) represent an era of societal prosperity in China. However, due to a lack of high-resolution paleoclimate records it is still unclear whether the agricultural boost documented for this period was associated with more favorable climatic conditions. Here, multiparameter analysis of annually resolved tree-ring records and process-based physiological modeling provide evidence of stable and consistently humid climatic conditions during 270 to 77 BCE in northern China. Precipitation in the Asian summer monsoon region during the Qin-Western Han Dynasties was ~18 to 34% higher compared to present-day conditions. In shifting agricultural and pastoral boundaries ~60 to 100 km northwestward, possibility up to 200 km at times, persistently wetter conditions arguably increased food production, contributing to the socioeconomic prosperity around 2,200 y ago. A gradual wetting trend in the western part of arid northwestern China since the 1980s resembles the historical climate analogue, suggesting that similar benefits for regional environmental and agricultural systems may reoccur under current climate change, at least in the near term. [ABSTRACT FROM AUTHOR]

Globally, there has been a lot of focus on climate variability, especially variability in annual precipitation and temperatures. Depending on the area, different climate variables have different degrees of variation. Therefore, analyzing the temporal and spatial changes or dynamics of meteorological or climatic variables in light of climate change is crucial to identifying the changes induced by climate and providing workable adaptation solutions. This study examined how climate variability affects tea production in Darjeeling, West Bengal, India. It also looked at trends in temperature and rainfall between 1991 and 2023. In order to identify significant trends in these climatic factors and their relationship to tea productivity, the study used a variety of statistical tests, including the Sen's Slope Estimator test, the Mann–Kendall's test, and regression tests. The study revealed a positive growth trend in rainfall (Sen's slope = 0.25, p = 0.001, R2 = 0.032), maximum temperature (Sen's slope = 1.02, p = 0.026, R2 = 0.095), and minimum temperature (Sen's slope = 4.38, p = 0.006, R2 = 0.556). Even with the rise in rainfall, there has been a decline in tea productivity, as seen by the sharp decline in both the tea cultivated area and the production of tea. The results obtained from the regression analysis showed an inverse relationship between temperature anomalies and tea yield (R = −0.45, p = 0.02, R2 = 0.49), indicating that the growing temperatures were not favorable for the production of tea. Rainfall anomalies, on the other hand, positively correlated with tea yield (R = 0.56, p = 0.01, R2 = 0.68), demonstrating that fluctuations in rainfall have the potential to affect production but not enough to offset the detrimental effects of rising temperatures. These results underline how susceptible the tea sector in Darjeeling is to climate change adversities and the necessity of adopting adaptive methods to lessen these negative consequences. The results carry significance not only for regional stakeholders but also for the global tea industry, which encounters comparable obstacles in other areas. [ABSTRACT FROM AUTHOR]

The conservation of the olive ridley turtle (Lepidochelys olivacea) is increasingly critical due to declining global populations. This study investigates the influence of hydrometeorological conditions on the nesting season and annual hatchling sex ratios conducted at the Playón de Mismaloya Federal Reserve in Tomatlán, Jalisco, Mexico. The research specifically examines variations in sand temperature at both the beach surface and nesting depths, with extended measurements taken at multiple depths (20, 40, 60, 80, and 100 cm) to analyze the vertical temperature gradient along the beach. Atmospheric parameters were modeled using Newton's Cooling Law and solved with the finite difference method to estimate heat loss rates from beach sand to its surroundings, shedding light on microclimatic effects on incubation and embryonic development. Meteorological data were gathered from an automatic weather station, while sand temperatures were monitored with thermographs. During the warm period (approximately 32 °C), sand temperature showed a negative correlation with depth (20–100 cm), indicating cooler temperatures at greater depths. These conditions were associated with female-biased hatchling production. Conversely, the cold period (approximately 28 °C) led to male-biased hatchling production, with a positive correlation between sand and air temperatures. This study emphasizes the importance of monitoring in situ environmental conditions and extending the protection season until February to avoid the loss of male hatchlings. [ABSTRACT FROM AUTHOR]

Determining the factors that drive vegetation variation is complicated by the intricate interactions between climatic and anthropogenic influences. Neglecting the short-term time-lag and cumulative effects of climate on vegetation growth (i.e., temporal effects) exacerbates the uncertainty in attributing long-term vegetation dynamics. This study evaluated the climatic and anthropogenic influences on vegetation dynamics in China from 2000 to 2019 by analyzing normalized difference vegetation index (NDVI), temperature, precipitation, solar radiation, and ten anthropogenic indicators through linear regression, correlation, multiple linear regression (MLR), residual, and principal component analyses. Across most regions, growing season NDVI (G-NDVI) exhibited heightened sensitivity to climatic variables from earlier periods or from both earlier and current periods, signaling extensive temporal climatic effects. Constructing new time series for temperature, precipitation, and solar radiation from 2000 to 2019, based on the optimal vegetation response timing to each climatic variable, revealed significant correlations with G-NDVI across 27.9%, 26.7%, and 23.3% of the study area, respectively. Climate variability and anthropogenic activities contributed 45% and 55% to the G-NDVI increase in China, respectively. Afforestation significantly promoted vegetation greening, while agricultural development had a marginally positive influence. In contrast, urbanization negatively impacted vegetation, particularly in eastern China, where farmland conversion to constructed land has been prevalent over the past two decades. Neglecting temporal effects would significantly reduce the areas with robust MLR models linking G-NDVI to climatic variables, thereby increasing uncertainty in attributing vegetation changes. The findings highlight the necessity of integrating multiple anthropogenic factors and climatic temporal effects in evaluating vegetation dynamics and ecological restoration. [ABSTRACT FROM AUTHOR]

The influence of biomass burning (BB) aerosols arising from wildfires and agricultural fires on the transient coupled evolution of El Niño–Southern Oscillation (ENSO) is explored in Community Earth System Model, version 2 (CESM2). For both El Niño and La Niña, two 20-member ensembles are generated from initial states that are predisposed to evolve into ENSO events. For each ENSO phase, one ensemble is forced with the observed BB emissions during satellite-era ENSO events while the other is forced with a climatological annual cycle, with the responses to anomalous BB emissions estimated from interensemble differences. It is found that the regional responses to anomalous BB emissions occur mainly during boreal fall, which is also the time of the climatological seasonal maximum in emissions. Transient responses are identified in precipitation, clouds, and radiation in both the tropics and extratropics. At the onset of El Niño, these include increased precipitation in the northern branch of the intertropical convergence zone (ITCZ) and an enhancement of cloud albedo and amount across the Maritime Continent and eastern subtropical Pacific Ocean. Additional responses are identified through the course of El Niño and successive La Niña events, the net effect of which is to strengthen sea surface temperature (SST) anomalies in the eastern Pacific Ocean during El Niño and warm the tropical Pacific Ocean during La Niña. These responses improve the simulation of ENSO power, diversity, and asymmetry in CESM2. Significance Statement: Biomass burning emissions from both wildfires and agricultural fires during ENSO act as a climate feedback, as they are both driven by fire weather anomalies tied to ENSO and influence clouds, radiation, and precipitation on a global scale. While the largest biomass burning (BB) emissions emanate mainly from Indonesia, other regions also exhibit systematic responses. When simulated in CESM2, the emissions collectively impact the flows of energy across the tropical Pacific Ocean in a spatially and temporally complex fashion, with the net effect of improving CESM2's simulation of ENSO events. [ABSTRACT FROM AUTHOR]

In this study, the potential changes in tropical cyclone (TC) lifetime in the western North Pacific basin are examined for different future climates. Using homogeneous 9-km-resolution dynamical downscaling with the Weather Research and Forecasting (WRF) Model, we show that TC-averaged lifetime displays insignificant change under both low and high greenhouse gas concentration scenarios. However, more noticeable changes in the tails of TC lifetime statistics are captured in our downscaling simulations, with more frequent long-lived TCs (lifetime of 8–11 days) and less short-lived TCs (lifetime of 3–5 days). Unlike present-day simulations, it is found that the correlation between TC lifetime and the Niño index is relatively weak and insignificant in all future downscaling simulations, thus offering little explanation for these changes in TC lifetime statistics based on El Niño–Southern Oscillation. More detailed analyses of TC track distribution in the western North Pacific basin reveal, nevertheless, a noticeable shift of TC track patterns toward the end of the twenty-first century. Such a change in TC track climatology results in an overall longer duration of TCs over the open ocean, which is consistent across future scenarios and periods examined in this study. This shift in the TC track pattern is ultimately linked to changes in the western North Pacific subtropical high, which retreats to the south during July and to the east during August–September. The results obtained in this study provide new insights into how large-scale circulations can affect TC lifetime in the western North Pacific basin in warmer climates. Significance Statement: Using high-resolution dynamical downscaling with the Weather Research and Forecasting (WRF) Model under low- and high-emission scenarios, this study shows that the basin-averaged tropical cyclone (TC) lifetime in the western North Pacific (WNP) basin has no noticeable change under both warmer climate scenarios, despite an overall increase in TC maximum intensity. However, the tails of the TC lifetime distribution display significant changes, with more long-lived (6–20 days) TCs but less short-lived (3–5 days) TCs in the future. These changes in TC lifetime statistics are caused by the shift of the North Pacific subtropical high, which alters large-scale steering flows and TC track patterns. These results help explain why previous studies on TC lifetime projections have been inconclusive in the WNP basin and provide new insights into how large-scale circulations can modulate TC lifetime in a warmer climate. [ABSTRACT FROM AUTHOR]

ABSTRACT Understanding seasonal rainfall patterns and variability is crucial for managing water resources, pastoral and agricultural activities in Ethiopia, an especially climate‐vulnerable country. This study examines trends in March–April–May (MAM) rainfall from 1981 to 2022, emphasising the relationships between climate indices, atmospheric circulation patterns, and variations in precipitation. By utilising daily CHIRPS rainfall data and monthly sea surface temperature (SST), sea level pressure (SLP) and other reanalysis datasets, we applied extreme indices analysis, correlation analysis and Student's t‐tests to compare climate factors and rainfall during two distinct periods 1(981–2001 and 2002–2022) and assess changes relative to the 1991–2020 long‐term mean. Our findings reveal a notable shift towards warmer sea surface temperature (SST) phases in key ocean basins, with significant positive correlations (r > 0.45, p < 0.05) between Ethiopian MAM rainfall and SSTs in the Mediterranean, Northwest Pacific, Northern Atlantic and Western Indian Ocean. Precipitation patterns shifted from above‐average to below‐average rainfall, aligning with opposite trends in the tropical central Indian Ocean. A long‐term trend analysis revealed a marked decrease in rainy days across northeast, east, central, south and southeastern Ethiopia during 2002–2022, with an increase in consecutive dry days and a decrease in consecutive wet days, with statistical significance at the 95% confidence level. The period from 2002 to 2022 was characterised by La Niña‐like conditions and a negative Pacific Decadal Oscillation, which had a considerable impact on rainfall patterns. Changes in large‐scale atmospheric circulation reduced moisture transport to Ethiopia, leading to drier conditions. These findings enhance our understanding of Ethiopian rainfall variability and its drivers, crucial for improving early warning systems and developing climate adaptation strategies in the region. [ABSTRACT FROM AUTHOR]

In this study, we investigated the influence of climatic factors on rice yields across different growth stages and predicted future rice yields in different regions of South Korea. The results revealed that although climatic factors had limited effects during the vegetative growth stage, significant correlations were observed during the reproductive growth and ripening stages, with distinct positive, negative, and positive relationships between rice yield and daily temperature range, precipitation, and duration of sunshine, respectively. Multiple regression analysis of climatic factors showed that rice yield variability, ranging from 15.4% to 80.9%, was mainly due to precipitation and the daily temperature range during the reproductive growth and ripening stages. Climate change scenarios may result in the improvement or deterioration of rice yields across different regions. Rice yields are predicted to increase in most regions, although some southern coastal areas may experience decreased yields. This study highlights the need for strategies to address expected fluctuations in rice yield resulting from increased climate variability. These findings provide valuable insights for developing climate change adaptation measures for rice agriculture in South Korea. [ABSTRACT FROM AUTHOR]