Global Climate Variability Research Articles

Wind regime changes on the shipping routes of the Russian seas at the end of the 20th – beginning of the 21st centuries

This article aims to assess wind regime variations in the Russian seas and identify shipping and fishing areas where the frequency of dangerous winds showed statistically significant upward trends. The assessment is based on ERA-5 global atmospheric reanalysis data on hourly mean wind velocity from 1991–2020. The methodology employed standard statistical methods for data processing. The results of the assessment of increased storm risks across all Russian seas are summarized in a table. The study confirms that the wind regime in the Russian seas is non-stationary and responds to global climate variations. The most dynamic changes in wind conditions occur in the open seas (Bering, Barents), which have free exchange with external seas and oceans. The greatest risks to shipping and fishing, associated with an increased frequency of dangerous winds given medium or high climatic norms for this indicator, were identified in the following areas: the northeastern part of the Black Sea, including approaches to the ports of Novorossiysk, Tuapse, and the Kerch Strait area (winter season); the Baltic Sea, including shipping lanes in its central part and the Gulf of Finland (winter season); the Barents Sea (winterspring season); the southwestern part of the Bering Sea, including sections of transoceanic routes (winter season); and the northwestern sector of the Pacific Ocean, including sections of shipping lanes and fishing areas off the eastern coasts of Kamchatka and the Kuril Islands (winter-spring season). It is noted that ship crews and shipping company personnel should account for the increasing storm risks when planning navigation in these areas (especially those with harsh climates) and take measures to minimize them, including considering alternative routes. Emphasis is placed on the critical importance of the quality of training of ship crews for navigation in storm conditions, icing, steering failure, and assisting vessels in distress.

Meteorological and Environmental Drivers of Cardiovascular Health Risk in an Insular Region (Azores)

Some authors share the same opinion that climatic and environmental parameters are strongly linked to health. This study investigates the impact of climatic and environmental factors on hypertension, cardiovascular and circulatory system disease admissions in the Faial Hospital. Faial is in the Azores, an insular region of Portugal. With the rise in global climate variability, understanding local effects on public health has become increasingly crucial, particularly in insular regions like the Azores. This research utilizes epidemiological, meteorological, and air quality data from Faial Island, collected from 2010 to 2019, to analyze the correlation between hospital admissions due to hypertension, circulatory and cardiovascular system diseases and variations in meteorological parameters (e.g., daily minimum, daily maximum and daily average temperature, relative humidity, wind speed, thermal amplitude, dew point, average total precipitation and atmospheric pressure at mean sea level) and air pollutants (e.g., nitrogen dioxide, sulfur dioxide, ozone and particulate matter with diameter less than ten micrometers). The study uses statistical methods such as time series analysis, weekly percentile intervals, and principal component analysis (PCA). These methods reveal a seasonal pattern in hospital admissions related to meteorological conditions and air quality. Specifically, higher rates of admissions are associated with increased precipitation, wind speed, and temperature fluctuations during winter months. In contrast, summer shows lower admission rates corresponding to lower humidity and precipitation levels. These findings show that human health is highly sensitive to air quality and climatic conditions. This highlights the need for adaptive healthcare strategies amid environmental changes. The insights gained from this study underscore the importance of integrating meteorological and air quality monitoring into public health planning. Integrating monitoring systems is particularly crucial in regions facing dual challenges of climate change and limited healthcare resources. Proactive measures like early warning systems, predictive models, and public awareness campaigns can reduce health risks for vulnerable populations. By addressing critical knowledge gaps, this study contributes to the growing body of evidence on the interconnections between climate, air quality, and public health, providing a foundation for region-specific policies aimed at enhancing resilience to environmental changes. The findings contribute to a deeper understanding of the climate-health relation, offering a framework for developing region-specific policies to enhance resilience in the face of ongoing global environmental changes.

Early Detection of Water Stress in Kauri Seedlings Using Multitemporal Hyperspectral Indices and Inverted Plant Traits

Global climate variability is projected to result in more frequent and severe droughts, which can have adverse effects on New Zealand’s endemic tree species such as the iconic kauri (Agathis australis). Several studies have investigated the physiological response of kauri to medium- and long-term water stress; however, no research has used hyperspectral technology for the early detection and characterization of water stress in this species. In this study, physiological (stomatal conductance (gs), assimilation rate (A), equivalent water thickness (EWT)) and leaf-level hyperspectral measurements were recorded over a ten-week period on 100 potted kauri seedlings subjected to control (well-watered) and drought treatments. In addition, plant functional traits (PTs) were retrieved from spectral reflectance data via inversion of the PROSPECT-D radiative transfer model. These data were used to (i) identify key PTs and narrow-band hyperspectral indices (NBHIs) associated with the expression of water stress and (ii) develop classification models based on single-date and multitemporal datasets for the early detection of water stress. A significant decline in soil water content and physiological responses (gs and A) occurred among the trees in the drought treatment in weeks 2 and 4, respectively. Although no significant treatment differences (p > 0.05) were observed in EWT across the whole duration of the experiment, lower mean values in the drought treatment were apparent from week 4 onwards. In contrast, several spectral bands and NBHIs exhibited significant differences the week after water was withheld. The number and category of significant NBHIs varied up to week 4, after which a substantial increase in the number of significant indices was observed until week 10. However, despite this increase, the single-date models did not show good model performance (F1 score > 0.70) until weeks 9 and 10. In contrast, when multitemporal datasets were used, the classification performance ranged from good to outstanding from weeks 2 to 10. This improvement was largely due to the enhanced temporal and feature representation in the multitemporal models. Among the input NBHIs, water indices emerged as the most important predictors, followed by photochemical indices. Furthermore, a comparison of inverted and measured EWT showed good correspondence (mean absolute percentage error (MAPE) = 8.49%, root mean squared error (RMSE) = 0.0026 g/cm2), highlighting the potential use of radiative transfer modelling for high-throughput drought monitoring. Future research is recommended to scale these measurements to the canopy level, which could prove valuable in detecting and characterizing drought stress at a larger scale.

Investigation of Climatic Factors Affecting the Amount of Foraged Matsutake Mushrooms in Korea

Tricholoma matsutake is a valuable edible mushroom in Eastern Asia. Due to the challenges of artificial cultivation, T. matsutake cultivation has relied on foraging from pine forests. Changes in global climate variables, such as temperature and precipitation, could affect the amount of foraged T. matsutake. In this study, we investigated the correlation between the amount of foraged T. matsutake and climatic factors (average monthly temperature and precipitation) in Yangyang-gun using the augmented Dickey–Fuller test and the ordinary least squares method. Among the assessed correlations between the foraged T. matsutake and different climatic factors, the average temperature in August was significantly correlated with the amount of foraged T. matsutake, increasing by 1.5 tons when the temperature in August increased by 1 unit. Overall, this study identified a potentially strong positive correlation between the average temperature in August and amount of foraged T. matsutake.

Removing Climatic Overprints in Sedimentary Cosmogenic Beryllium Records: Potentials and Limits

AbstractContinuous reconstructions of past variations of the Earth's magnetic field are based mainly on paleomagnetic and cosmogenic 10Be records in marine sediments. In both cases, the recording mechanisms can be affected by environmental processes. Climatic overprints are only partially removed by normalization procedures, so that stacking is used to further remove site‐specific effects. Regionally or globally correlated artifacts, however, cannot be removed by stacking. Here we present a modified approach where geomagnetic records are complemented by environmental proxies representing processes that might affect the field recording mechanism. Geomagnetic and environmental records are jointly processed with principal component analysis to obtain a set of components supposed to represent true variations of the geomagnetic field and climatic overprints, respectively. After discussing the theoretical background of this new approach and its underlying assumptions, a practical example is presented, using a worst‐case scenario based on a single 10Be record from the North Atlantic with strong climatic overprints, covering the last 600 ka. The first two principal components, which represent the modulation of 10Be by global climatic variations and by the geomagnetic field, respectively, explain 66.3% of the signal variance. Comparison of the geomagnetic principal component with global relative paleointensity stacks shows that the original climatic overprint can be reduced by a factor of 2, outperforming a 10Be/9Be stack obtained from two sites with little glacial‐interglacial variability. The proposed method for removing climatic overprints can be applied to multiple sites more efficiently than conventional stacking.

Western Pacific Warm Pool Warming and Salinity Front Expansion Since 1821 Reconstructed From Paired Coral δ18O, Sr/Ca, and Reconstructed δ18Osw

AbstractThe Southwest Pacific region is of great importance to global climate variability, but instrumental climate observations before the 1980s lack in numbers and quality. Despite efforts in complementing instrumental records with proxy sea surface temperature (SST) and sea surface salinity (SSS) reconstructions based on coral Sr/Ca and δ18Osw records, few of them are longer than a century. This study introduces a northwestern extension to the existing records of South Pacific coral study sites with monthly‐resolved Sr/Ca, δ18O, and δ18Osw reconstructions from Rotuma dating back to 1821. Additionally, we present new monthly‐resolved Sr/Ca and reconstructed δ18Osw from a coral from Tonga dating back to 1848. Results reveal 1.5°C warming in the Western Pacific Warm Pool, while the adjacent coral from Tonga shows 1°C warming over the twentieth century. The Rotuma Sr/Ca record reveals thermal stress events impacting the Sr/Ca‐SST relationship in the following months. Coral δ18Osw results reveal significant freshening of 0.45 Sp (practical salinity unit) in Tonga since the early twentieth century, suggesting the southeastward expansion of the South Pacific Convergence Zone salinity front. The δ18Osw inferred SSS provides a valuable extension into the past considering the short and inconsistent instrumental records available. This study demonstrates the utility of coral‐based reconstructions in capturing long‐term and regional climate variations in the Southwest Pacific and the necessity of expanding replicated studies to other underrepresented areas to enhance our understanding of regional climate dynamics.

Climatic changes and their impact on living organisms

One of the issues that the world is currently concerned about is climate change. Climate change and its impact on the living world are of even greater concern to the world community. The recent changes in the atmosphere and unstable weather conditions are felt not only in Azerbaijan but also in many countries of the world. From numerous studies conducted over the last five years, it has become known that over the last hundred years, the average temperature on Earth has increased by 0.7 degrees Celsius (Mammadov, Khalilov, 2006: 222; 318). However, anthropogenic factors are mainly involved in the temperature rise. And the basis of anthropogenic factors are gases, nitrous oxide, nitrogen oxide, chlorofluoride compounds, carbon, methane, etc., causing thermal effects. For this reason, blizzards, thunderstorms, droughts, floods, and heavy rains, which are occurring everywhere, have intensified. Whereas in the oceans the water surface has warmed to a depth of 1,000 meters, this has recently changed to a depth of 2,000 meters. This leads to the formation of hot streams. Climate underlies all changes in general. These processes are also taking place in Azerbaijan. Only for the last hundred years has the average annual temperature on the territory of Azerbaijan increased by 0.4-1.3 degrees. Also, the number and strength of floods in mountain rivers in Azerbaijan increase every year. The factors influencing temperature changes in Azerbaijan are the Caspian Sea and the Greater and Lesser Caucasus Mountains. The presence of the Caspian Sea mitigates the effects of climate change in Azerbaijan (Kurayev, 2006: 16). There are also changes that occur independently of human activity. These changes fundamentally affect the processes occurring in the atmosphere and the health of living organisms, including humans. Increased solar activity, displacement of the Earth, the Moon, and other planets, methane entering the atmosphere, volcanic eruptions, etc. are examples of this. One of the most pressing problems on Earth is global warming and its complications. Global climate variability is based on the inexorable rise in temperature. Warming leads to climate change, ecosystem disruption, extreme weather variability, sea level rise due to melting ice, and loss of biodiversity. This has a negative impact on human health, agricultural and food security, and the economy. To this purpose, our state is fully prepared for COP-29, the 29th session of the Conference of the Parties to the UN Framework Convention on Climate Change, which it will host in 2024. All these activities will contribute in the near future. The different interactions of climate-forming factors in the world give rise to a rather large diversity of climates. The recent decrease in the amount of precipitation may lead to desertification in some areas of our republic.

Droughts of the early 19th century (1790–1830) in the northeastern Iberian Peninsula: integration of historical and instrumental data for high-resolution reconstructions of extreme events

Abstract. Drought represents a prevalent climate risk in the Mediterranean region. In the context of climate change, an increase in both frequency and intensity is anticipated over the next century. In order to effectively manage future scenarios where global warming overlays natural climate variability, a thorough analysis of the nature of droughts prior to the industrial age is crucial. This approach incorporates an extended temporal scale into the study of severe droughts, enabling the identification of low-frequency drought events that occurred before the instrumental period. The objective of this study is to examine the occurrence and magnitude of extreme droughts lasting over a year in the Spanish Mediterranean basin during the early 19th century (1790–1830). To achieve this objective, the research integrates the use of instrumental observations and information derived from historical documentary sources with daily to monthly resolutions (e.g., rogation ceremonies). The findings reveal that drought episodes were more frequent and severe during the early 19th century compared to the late 19th century. Moreover, drought episodes of similar severity were rare throughout the 20th century. Only in the current context of climate change, over the last 2 decades, has a pattern of high drought severity been identified that resembles the severity found during the early 19th century (especially between 1812 and 1825). This study underscores the presence of high variability in drought patterns over the last few centuries, justifying the need for intensified research on drought episodes with high temporal resolution for extended periods.

Autophagy Regulates Plant Tolerance to Submergence by Modulating Photosynthesis.

The increase in global climate variability has increased the frequency and severity of floods, profoundly affecting agricultural production and food security worldwide. Autophagy is an intracellular catabolic pathway that is dispensable for plant responses to submergence. However, the physiological role of autophagy in plant response to submergence remains unclear. In this study, a multi-omics approach was applied by combining transcriptomics, proteomics, and lipidomics to characterize molecular changes in the Arabidopsis autophagy-defective mutant (atg5-1) responding to submergence. Our results revealed that submergence resulted in remarkable changes in the transcriptome, proteome, and lipidome of Arabidopsis. Under submerged conditions, the levels of chloroplastidic lipids, including monogalactosyldiacylglycerol (MGDG), digalactosyldiacylglycerol (DGDG), and phosphatidylglycerol (PG), were lower in atg5-1 than in wild-type, suggesting that autophagy may affect photosynthesis by regulating lipid metabolism. Consistently, photosynthesis-related proteins and photosynthetic efficiency decreased in atg5-1 under submergence conditions. Phenotypic analysis revealed that inhibition of photosynthesis resulted in a decreased tolerance to submergence. Compared to wild-type plants, atg5-1 plants showed a significant decrease in starch content after submergence. Collectively, our findings reveal a novel role for autophagy in plant response to submergence via the regulation of underwater photosynthesis and starch content.

Cooling induced the stagnation of vermicularisation in the subtropical region of East Asia during the Late Quaternary

Cooling induced the stagnation of vermicularisation in the subtropical region of East Asia during the Late Quaternary

Quantifying the Role of Ocean Dynamics in SST Variability across GCMs and Observations

Abstract Midlatitude SSTs forced by mesoscale oceanic processes can affect the large-scale atmosphere, pointing to the ocean’s crucial role outside the tropics. Previous studies have shown oceanic mesoscale processes’ effect on global and regional climate variability. This study quantifies the local contribution of ocean dynamics to mixed-layer temperature across the globe by directly estimating the ocean heat flux divergence resolved by state-of-the-art ocean reanalysis, eddy-resolving, and eddy-parameterized versions of two U.S. national climate models and indirectly from air–sea flux satellite-based estimates. Our results show that the eddy-resolving climate simulations resolve mixed-layer temperature variances that are larger and closer to those inferred from observations than both their eddy-parameterized counterparts and ECCO over much of the extratropics. The observations and the eddy-resolving models indicate a more significant role of ocean dynamics in the mixed-layer temperature variability than the surface fluxes over most extratropics compared to their eddy-parameterized versions. A frequency domain analysis shows that the better-resolved ocean mesoscale and thermal gradients enhance the variance over a time scale from 2 months to 30 years. Results show agreement in the ocean’s contribution among satellite-based estimates, ocean reanalysis products, and ocean eddy-resolving simulations. At the same time, differences emerge for ECCO and the eddy-parameterized models, suggesting that surface fluxes account for a larger fraction of the mixed-layer temperature variability in most of the extratropics.

The Impact of Climate Change on Cropping Patterns in the Jurang Sate Hulu Irrigation Area

For many years, the active management of the Jurang Sate Hulu Irrigation Area has provided significant benefits to cropping patterns. However, the impacts of climate change on water availability and temperature variations present critical challenges to crop productivity. Therefore, an analysis of the effects of climate change is essential. The methods employed in the analysis of climate change include correlation and regression methods. This study uses nine variables of global climate change. The correlation method is applied to determine the extent of the influence of global climate variables, represented by Global Circulation Model (GCM) data, on rainfall and climate in the Jurang Sate Hulu Irrigation Area. The regression method is used to validate the prediction model for rainfall from 2024 to 2100. In the cropping pattern analysis, the Penman-Monteith method is used to calculate evapotranspiration, while the F.J. Mock method is used to calculate flow discharge. Based on the analysis, the global climate variables that most significantly influence rainfall in the Jurang Sate Hulu Irrigation Area are air temperature, wind speed, eastward wind, and surface temperature, with maximum correlation values of 0.551, 0.540, 0.589, and 0.625, respectively. In contrast, local climate variables have less influence, as they yield correlation values below 0.500. The regression analysis showed an average validation result for the selected model using two goodness-of-fit parameters: Root Mean Square Error (RMSE) of 124.371 and Nash-Sutcliffe Efficiency (NSE) of 0.403. The highest irrigation water requirement occurs during the third planting period, from 2051 to 2075, at 0.465 m³/s. The planned cropping pattern is paddy-paddy-second crops, with planting areas of 3,807 hectares for the period from 2024 to 2050, 3,595 hectares for the period from 2051 to 2075, and 3,383 hectares for the period from 2076 to 2100, with a total planting intensity of 300% during each period.

Socio-Economic Implications of Snow Cover Area in the Upper Indus Basin

The Indus River, one of the principal waterways in Asia, specifically the Indian Subcontinent, originates from the Himalayan Region and Qinghai-Tibet Plateau. Understanding snow cover dynamics is one of the most vital components for effective hydrological resource management and assessing the impacts of local, regional, and global climatic variations. Variations in the radiation of snow microstructures and snowpacks have profound socio-economic and environmental consequences, affecting agricultural productivity, reservoir supply for factories, environmental sustainability, governance of land resources, and overall community resilience. Fluctuations in snowmelt patterns can lead to water shortages or surplus, influencing food security and economic stability in a country largely dependent on agriculture. Utilizing Moderate Resolution Imaging Spectroradiometer (MODIS) satellite data, this study assesses the implications of Snow Cover Area (SCA) on water security and livelihood of agricultural-related sectors. A comparative analysis of snow cover reveals a shifting trend in the accumulation period, with notable anomalies affecting the agricultural output, which affects the household income related to the agricultural sector. This research underscores the necessity of adapting water management strategies to align with evolving snow cover dynamics to mitigate potential socio-economic risks.

Long-Term Changes in Deep Ocean Currents between Ulleung Island and Dok Island in the East Sea from 1996 to 2023

This study presents a comprehensive analysis of long-term deep ocean currents between Ulleung Island and Dok Island in the East Sea, based on data observed from the East Sea Current Measurement 1 (EC1) mooring station spanning from 1996 to 2023. The deep current at the Ulleung Interplain Gap, a trough situated between Ulleung Island and Dok Island, originates from the Japan Basin, a region where deep water formation occurs within the East Sea. The southward flow and velocity of this deep water are reflective of both regional and global climate dynamics. Understanding these dynamics is crucial for assessing environmental impact, both locally in Korea and globally. Significant trends and anomalies were identified in the zonal and meridional velocities within the 1,800 and 2,500-meter depth range. Data from 2012 to 2014 required corrections due to unit inconsistencies, which, after adjustment, revealed a deceleration of the southward bottom current, with speeds decreasing from 1.49 cm s<sup>-1</sup> in November 1996 to 1.14 cm s<sup>-1</sup> in April 2023. These changes may be linked to global climate variations and bottom water formation in the Japan Basin, influencing regional circulation patterns. The findings highlight the importance of sustained ocean monitoring and enhanced data management to ensure the accuracy and utility of long-term oceanographic datasets.

Impact of paclobutrazol on the initial growth of Tectona grandis clones under different water availability regimes

Plantations continually confront climatic challenges that may impede their initial establishment in the field, thereby adversely affecting their overall productivity. In order to establish protocols for forest plantations that address potential challenges arising from global climate variations, growth regulators play a significant role. The use of plant growth regulators in early forest species’ growth and establishment stages is limited. The present study assessed the morphophysiology of Tectona grandis clones in response to different water regimes and paclobutrazol concentrations applied to the soil. The experiment followed a randomized block design with four blocks and a 5x3 factorial scheme. This scheme included five concentrations of PBZ: 0.0 (control), 1.0, 2.0, 4.0, and 8.0 mg plant-1, and three levels of water availability: 40%, 70%, and 100% of field capacity. There was no interaction between PBZ concentration and water regime factors. Based on the analysis applied to each treatment, plants’ morphological and physiological variables did not respond to the use of different PBZ concentrations, although significant differences were observed in some morphological and physiological traits. The higher water availability provided by 100% field capacity led to the highest increase in stem diameter, root and total dry mass values. Tectona grandis clones presented increased carboxylation efficiency and water-use efficiency at 40% field capacity. Keywords: drought tolerance, field capacity, morphological changes, PBZ.

A 485-million-year history of Earth’s surface temperature

A long-term record of global mean surface temperature (GMST) provides critical insight into the dynamical limits of Earth’s climate and the complex feedbacks between temperature and the broader Earth system. Here, we present PhanDA, a reconstruction of GMST over the past 485 million years, generated by statistically integrating proxy data with climate model simulations. PhanDA exhibits a large range of GMST, spanning 11° to 36°C. Partitioning the reconstruction into climate states indicates that more time was spent in warmer rather than colder climates and reveals consistent latitudinal temperature gradients within each state. There is a strong correlation between atmospheric carbon dioxide (CO 2 ) concentrations and GMST, identifying CO 2 as the dominant control on variations in Phanerozoic global climate and suggesting an apparent Earth system sensitivity of ~8°C.

Rice yield prediction through integration of biophysical parameters with SAR and optical remote sensing data using machine learning models

In an era marked by growing global population and climate variability, ensuring food security has become a paramount concern. Rice, being a staple crop for billions of people, requires accurate and timely yield prediction to ensure global food security. This study was undertaken across two rice crop seasons in the Udham Singh Nagar district of Uttarakhand state to predict rice yield at 45, 60 and 90 days after transplanting (DAT) through machine learning (ML) models, utilizing a combination of optical and Synthetic Aperture Radar (SAR) data in conjunction with crop biophysical parameters. Results revealed that the ML models were able to provide relatively accurate early yield estimates. For summer rice, eXtreme gradient boosting (XGB) was the best-performing model at all three stages (45, 60, and 90 DAT), while for kharif rice, the best-performing models at 45, 60, and 90 DAT were XGB, Neural network (NNET), and Cubist, respectively. The combined ranking of ML models showed that prediction accuracy improved as the prediction date approaches harvest, and the best prediction of yield was observed at 90 DAT for both summer and kharif rice. Overall rankings indicate that for summer rice, the top three models were XGB, NNET, and Support vector regression, while for kharif rice, these were Cubist, NNET, and Random Forest, respectively. The findings of this study offer valuable insights into the potential of the combined use of remote sensing and biophysical parameters using ML models, which enhances food security planning and resource management by enabling more informed decision-making by stakeholders such as farmers, policy planners as well as researchers.

Evaluating the impact of phyto-hormones on the morpho-biochemical traits of soybean through seed treatment and foliar application

Evaluating the impact of phyto-hormones on the morpho-biochemical traits of soybean through seed treatment and foliar application

Examining relations between sea-level anomalies in the Niño 3.4 region and terrestrial hydroclimatic conditions in China

Examining relations between sea-level anomalies in the Niño 3.4 region and terrestrial hydroclimatic conditions in China

Precipitation changes alter plant dominant species and functional groups by changing soil salinity in a coastal salt marsh

Precipitation changes alter plant dominant species and functional groups by changing soil salinity in a coastal salt marsh