Climate, Volume 11, Issue 4 (April 2023) – 17 articles

Two late Holocene cold events were described for the Southern Russian Far East: 2800–2600 year BP and the Little Ice Age (LIA) (~1300–1850 CE). The synthesis is based on multi-proxy records on profile “the mainland (Primorye)-islands (Sakhalin-Kurils)”. Main archives are sediments of small lakes and peat bogs that recorded the high-resolution environmental changes. The temporal resolution of reconstructions here is up to 26–40 years. During the cold event of 2800–2600 year BP, the humidity decreased sharply, there were long-term dry seasons without strong floods, and buried soil formed on floodplains. The LIA was wet in the mainland and the Kurils, with frequent strong floods, but was drier in Sakhalin. The cooling was characterized by sharp temperature fluctuations where high moisture conditions alternated with short-term drier periods. The shift in geographical position and intensity of the main centers of atmospheric action caused a paleoclimatic interpretation of these events (Aleutian Low, Siberian and North Pacific Highs, the summer Okhotsk anticyclone and the Far East depression). Changes in the North Pacific oscillations played an important role in the alternation of cold-dry and cold-wet periods. Anomalies in the intensity of El Niño and the monsoon system led to changes in tropical and extratropical cyclone trajectories and cyclogenesis in general. Full article

Background: Climate changes (CC) is one of the most important insidious crises affecting all countries in the world in the 21st century, including Algeria, and it is projected to affect many people in the future. Mitigation of the effects of this phenomenon will certainly involve environmental education, especially among university students. Therefore, evaluating their level of knowledge could help us understand to what extent they are prepared to contribute in the global efforts to fight against this catastrophe. Objective: The current study aims to investigate the perception and knowledge of Algerian students about climate change and its potential relationship with the COVID-19 pandemic. Methods: An online cross-sectional survey was conducted on a sample of 204 Algerian students by adopting snowball sampling during the academic year (2022/2023), with a questionnaire based on Google Forms. Data were analyzed using SPSS software. Results: The results obtained showed that 95.6% of the students asked had heard about this phenomenon and more than 90% perceived that it was really happening. The level of knowledge is significantly associated with age, where students aged between 20 and 30 years old had a lower level of knowledge than those over 30 years old (OR = 0.22, p = 0.027). Furthermore, students of the Humanities have shown the lowest level of knowledge compared to those of other domains. Regarding their attitude, only 31.8% of the asked students declared that they changed their attitude positively during the COVID-19 pandemic. The change in attitude and concern is statistically associated neither with the level of knowledge and perception nor COVID-19 affection, psychological impact, and uptake of the COVID-19 vaccine. Conclusion: The study concluded that there was a high level of awareness and a medium level of knowledge about CC among Algerian university students. However, most of them were either very worried or a little worried about this phenomenon. It was also suggested that the average level of knowledge about cause and effect and pandemic resistance could be attributed to the scientific study path of students from the study sample. The results of this study could be used as a baseline for future research into CC knowledge and perception in Algeria. Full article

Climate change in the coming decades could intensify extreme events such as severe droughts. Combined with the possible increase of water demands, these changes exert a great deal of pressure on the water systems. In order to confirm this assumption, a set of scenarios was proposed in this study to consider the combined impact of climate changes and the increase in water demand on the main multiple-use reservoirs of São Francisco River, Brazil. For this purpose, five CMIP6 climate models were used, considering two greenhouse gas emissions scenarios: the SSP2-4.5 and SSP5-8.5. The affluent natural flows and regulated flows were estimated to the adopted reservoirs considering all existing, new and projected demands. The combination of scenarios indicated an increase in Potential Evapotranspiration; possible significant reduction in water availability, with a decrease in precipitation with a magnitude of −15% in the most pessimistic scenarios and a decrease in flows with a magnitude varying between −5% and −40% in the Sobradinho and Três Marias reservoirs; growth in water demand, mainly for irrigation, with annual rates of 6.80%, 7.42%, 10.99% and 9.29% for Itaparica, Sobradinho, Três Marias and Retiro Baixo, respectively; and a substantial reduction in the performance of the evaluated reservoirs, mainly for the Retiro Baixo and Itaparica reservoirs, which showed a high vulnerability index and a low sustainability index. Full article

This work seeks an automatic algorithm to determine the primary meteorological cause(s) of individual extreme precipitation events. Such determinations have been made before, but required a by-hand analysis of each separate event. This is very time-consuming and the field would benefit from an automatic process. This is especially relevant when comparing different datasets to determine which ones most closely hew towards reality. This paper tests three simple metrics over the continental United States using the European Center for Medium-Range Weather Forecasting’s (ECMWF) atmospheric reanalysis (ERA5). The metrics tested measure and compare the strength of three meteorological processes associated with extreme precipitation: fronts, convection, and cyclones. A multivariate statistical technique as well as individual case studies show evidence that the three meteorological processes of interest cannot be isolated from one another using these simple physical metrics. This shows the difficulty in finding “pure” cases of these precipitation-generating processes and suggests approaching these processes with an eye toward mixed-type events. Full article

Among techniques proposed to limit global warming, there is Stratospheric Aerosol Geoengineering (SAG) which is aiming to increase Earth-atmosphere albedo by injecting sulfur dioxide into the stratosphere in order to reduce the solar radiation that reaches the earth. This study aims to assess the potential impact of SAG on Sea Surface Temperature (SST) in the Northern Gulf of Guinea and its causes using GLENS (Geoengineering Large Ensemble) simulations performed under a high anthropogenic emission scenario (RCP8.5). Here, we focus on two dynamically different regions: Sassandra Upwelling in Côte d’Ivoire (SUC, located east of Cape Palmas) and Takoradi Upwelling in Ghana (TUG, located east of Cape Three Points). Results show that in the SUC region, under climate change, there is an increase in SST (referred to as the current climate) all year long (by 1.52 °C on average) mainly due to an increase in net heat flux (lead by the decrease in longwave radiation) and also in weak vertical mixing (caused by strong stratification which dominates the vertical shear). Under SAG, SST decreases all the seasonal cycle with its maximum in December (−0.4 °C) due to a reduction in the net heat flux (caused by a diminution of solar radiation) and an increase in vertical advection (due to an increase in vertical temperature gradient and vertical velocity). In the TUG region, under climate change, SST warming is a little more intense than in the SUC region and SST changes are driven by an increase in the net heat flux and strong stratification. The cooling of the SST in TUG is similar to the SUC region, but contrary to this region, the cooling under SAG is not only explained by a decrease in the net heat flux but also by the remote forcing of wind changes at the western equatorial Atlantic. Full article

The agriculture sector in the Savanna region of Togo is especially vulnerable to weather fluctuations, which have an impact on crop production levels. However, farmers’ decisions to implement adaptation strategies are directly related to their perceptions of climate change risk. The current study employed a participatory workshop and household survey of 425 farmers to examine the drivers of specific climate change risks of interest (risk of loss of livelihood for farmers) and measure farmers’ level of climate change risk perception. A climate change risk perception score (CCRPS), descriptive statistics, principal component analysis, and K-means cluster analysis were used to analyze the data collected. The findings revealed that the most important changes in climate conditions affecting agricultural production in the study area were mainly the increased duration of dry spells, erratic rainfall, and an increase in extreme rainfall events. These climatic variations cause more floods and droughts, which, when coupled with socio-ecological vulnerability drivers, increase the impact of these events on agricultural livelihood, expose more farmers and their farmland, and contribute to the risk of farmers’ livelihood loss in the study area. Based on farmers’ appraisals of the occurrence of hazards, their exposure, and their vulnerability, farmers’ perceptions of climate risk have been classified into three categories: high, moderate, and low. This finding sheds some light on farmers’ climate change risk perception, which may influence their adaptation decision. These findings can be used to increase the uptake of adaptation strategies and thus the resilience of Savanna region agriculture to climate change. Full article

This study breaks away from traditional macroeconomic-data-based research that often overlooks the subjective experiences of communities and social groups in assessing their resilience to external stressors. Instead, we conducted a nuanced analysis of self-assessments provided by 364 household heads in the Nam Dong District, Thua Thien Hue Province, Vietnam, to gain a comprehensive understanding of household resilience. Our investigation focused on two upland communities—the Kinh majority and Co Tu ethnic minority households—evaluating their resilience levels in terms of the five livelihood capitals and identifying significant disparities among different ethnic and gender groups. Our findings reveal notable differences in livelihood resilience to climate change and variability among these groups, particularly for women, the poor, and ethnic minorities who exhibit lower resilience levels. This underscores the need for policies and programs designed to improve resilience capacity while taking into account these groups’ cultural and social norms. We suggest focusing on improving financial, human, and social capitals to increase households’ resilience to external shocks. Specifically, building resilience for disadvantaged groups must go hand in hand with promoting their overall well-being and alleviating poverty. Additionally, we recommend tailored training programs to raise awareness among households and strengthening institutional systems to enhance overall resilience. Full article

Agriculture is threatened by ever increasing temperatures and this trend is predicted to continue for the near and distant future. The negative impact of rising temperatures on agri-food systems is also compounded by the erratic and highly variable rainfall in most parts of southern Africa. Minimum and maximum temperatures’ variability and trend analysis were undertaken using daily time series data derived from 23 meteorological stations spread across Malawi, Mozambique, South Africa and Zimbabwe. The modified Mann–Kendall and Theil–Sen slope models were used to assess temperature trends and their magnitudes. Temperature varied with location and minimum temperature was more variable than maximum temperature. Semi-arid regions had higher variation in minimum temperature compared to humid and coastal environments. The results showed an upward trend in minimum (0.01–0.83 °C over a 33–38 year period) and maximum (0.01–0.09 °C over a 38–57 year period) temperatures at 9 and15 locations, respectively. A downward trend in minimum temperature (0.03–0.20 °C over 38–41 years) occurred in South Africa at two locations and Dedza (Malawi), while a non-significant decline in maximum temperature (0.01 °C over 54 years) occurred at one location in coastal dry sub-humid Mozambique. The results confirm the increase in temperature over 33–79 years, and highlight the importance of including temperature when designing climate change adaption and mitigation strategies in southern Africa and similar environments. Full article

Climate change is a critical challenge for the global grape and wine industry, as it can disrupt grapevine growth, production, and wine quality. Climate change could influence the cost-effectiveness and growth of the wine industry in different wine regions since grapevine development is deeply dependent on weather (short-term) and climate (long-term) conditions. Innovation and new technologies are needed to meet the challenge. This review article addresses the impact of climate change on grapevines, such as vine phenology, pest and disease pressure, crop load, and grape and wine composition. It also reviews recent advances in the areas of viticultural manipulation and relevant technologies to potentially reduce the impact of climate change and help growers improve grape quality. Remote sensing is used for vineyard microclimate monitoring; thermal sensors combined with UAVs, aircraft, or satellites are used for water management; soil electrical conductivity sensors have been developed for soil mapping. Viticultural manipulations, such as regulated deficit irrigation for water use efficiency and berry-ripening delay for growing quality fruit, are also discussed. The review assesses future directions for further technological development, such as soil and vine water monitoring devises, precision viticulture, and artificial intelligence in vineyards. Full article

Small-scale livestock farmers in the drylands of South Africa are highly exposed to agricultural drought-related food insecurity. Research has used descriptive analyses and missed the need to index the diversity of coping strategies used for managing agricultural drought-induced food insecurity. This study was conducted to bridge this gap using a two-step procedure. Initially, the study identified the farmers’ coping strategies and food security status. A coping strategy diversity index was computed using the Shannon–Weiner method and its relationship with the food security status was determined. Secondly, the determinants of the coping strategy diversity index were explored using an ordered logit regression model after testing for the proportional odds assumption. A mixed methods approach was utilized and a standardized questionnaire was administered to 217 smallholder livestock farmers in the Northern Cape province of South Africa. The household food insecurity mean score (8.429 ± 7.105) from the household food insecurity scale (HFIAS) was significantly related to a higher diversity of coping strategies. Similar results were reported for the household food insecurity access prevalence (HFIAP) status. The different forms of support (e.g., cash, food, training and assets) had a significant (p < 0.05) and positive effect on the coping strategy diversity index among the households. Education, access to credit and insurance facilities and the frequency of droughts significantly (p < 0.05) influenced the diversity of coping strategies under drought conditions. The utilization of cash reserves and investment stocks also significantly (p < 0.05) influenced the extent of coping strategy diversity. The study recommended strengthening the functional and technical capacity pillars of dealing with agricultural drought through strategic partnerships between the government and livestock value chain players. This collaboration should target affordable credit lines tailor-made for farmers to cope with agricultural drought. If well-coordinated, these interventions should reduce food insecurity prevalence, especially during drought conditions among vulnerable smallholder livestock farmers. Lessons from this study could also inform future research on the effectiveness of the current agricultural drought coping strategies while expanding the diversity clusters over space and time. Full article

Pacific islands have always been at the front of the great challenge of climate change. In this study, Mann–Kendall’s tau-based slope estimator was implemented to detect statistical trends in daily maximum and minimum temperatures of 2 stations and daily rainfalls at 14 stations over Guam for the period of 1953–2021, respectively, with 17 climate change detection indices. Mann–Kendall tests were implemented to the detection indices with respect to different time frames (i.e., annual, two-seasonal, and four-seasonal). The p-values from Mann–Kendall tests were used to determine the strength of trends, and Sen’s slopes were applied for the magnitudes of trends. The temperature trend analysis results indicate that Guam’s climate is getting warmer year by year. The increasing magnitudes of a seasonal maximum of daily maximum temperatures during the dry season are 0.036 °C/year for the dry season and 0.025 °C/year for the wet season at Anderson Airforce Base, while 0.031 °C/year and 0.023 °C/year for the dry and wet seasons at Guam International Airport. Trend analyses for temperatures have indicated that temperature during April through June has been increasing rapidly compared to other seasons. Strong trends in seasonal total rainfall amounts and the number of wet days were observed from July through December. The increasing trends in extreme rainfall indices during January–March and July–September periods would aggravate water quality due to the more sediments since important ecological reserve areas and coral reef areas are linked to watersheds in southern Guam. Full article

In order to better understand the extent to which global climate variability is linked to long-term mean and extreme sea level patterns, correlations between average sea levels at coastal sites throughout North America and low-frequency oscillations of several climate indices (CIs) were analyzed for the entire period of 1948–2018 as well as three equal-length sub-periods using correlation analysis. Correlation strength was assessed using Pearson’s correlation coefficient, while significance was estimated using Leave-One-Out Cross-Validation and a bootstrapping technique (p-value). The sliding window size, lag time, and beginning month were varied for optimal correlation; 60-month sliding windows, along with 0 lag time, resulted in the strongest correlations. Strong (r >= 0.60) and significant (p-value <= 0.05) correlations were identified. The Western Hemisphere Warm Pool Eastern Asia/Western Russia index and ENSO exhibited the strongest and most widespread correlation with coastal sea levels. Further analysis was performed to identify and quantify the magnitude of any sea level trends using the Theil–Sen estimator, while the Mann–Kendall (MK) test was used to estimate the significance of said trends. The results revealed that a complex set of ocean–atmosphere interactions govern long-term coastal sea level variability in large coastal regions of North America. The final results of this study allow a greater understanding of potential links between climate variability and long-term sea levels along the coasts of North America, as well as insights into sudden shifts in these relationships, which will contribute toward more accurate long-term forecasts. Full article

The evidence for the capacity of mangrove forests for coastal protection gained more importance within the recent decade because of important international agreements, such as the Sustainable Development Goals and Sendai Framework for Disaster Risk Reduction. However, the degree to which researchers agree on the capacity of mangroves to reduce coastal hazards is not fully established. This study employed a multilevel review process that selected 45 peer-reviewed articles for detailed analysis. Significant findings revealed a strong agreement amongst scientific literature on the benefits of mangrove forests in reducing coastal hazards. However, findings also revealed the dominance of single-discipline research, and less representation of countries in Africa and South America. Limitations in sampled studies highlight the limited number of global studies conducted on mangrove forests’ effectiveness in attenuating coastal hazards, and the limited representation of development and disaster studies. It is recommended that future research on mangrove forests and their coastal hazard reduction capacity should explore multidisciplinary approaches, and synergies in fieldwork and simulation methods while considering possible future climate change situations. Full article

Tree rings provide an invaluable insight into how trees adapt to changes in climate. This study presents aggregated results, from our research on tree rings, climatic response and the insect Choristoneura murinana infestations from three studies on Greek fir, located in stands across Central Greece and Giona Mountain on three different altitudes. In our studies, was found that extreme droughts and wet events had a negative or positive effect on fir growth, respectively. April’s precipitation had a positive correlation with growth for all the stands, which supports other authors’ findings. Moreover, the average maximum temperature of the growing season and the maximum temperature of April, July and August were also linked to growth. Evapotranspiration during the growing season was seen to be inversely proportional to the growth of fir. An apparent decline in tree ring growth more severe in stand 3 (Average Tree Ring Width Index, ARWI < 0.6) has been observed, particularly in recent years. The data suggests that temperature is having a detrimental effect on fir growth in the area, with a significant decreasing tendency in growth from 1993 for the high altitude stands and from 1998 for the lower altitude stand. To ensure successful and sustainable forest management in the future, more research into tree rings and their relationship with climate must be carried out. Full article

The complex dynamics of solar activity appear to be characterized by a number of oscillations ranging from monthly to multimillennial timescales, the most well-known of which being the 11-year Schwabe sunspot cycle. Solar oscillations are important because they also characterize the oscillations observed in Earth’s climate and can thus be used to explain and forecast climate changes. Thus, it is important to investigate the physical origin of solar oscillations. There appear to be two possibilities: either the oscillations in solar activity are exclusively controlled by internal solar dynamo mechanisms, or the solar dynamo is partially synchronized to planetary frequencies by planetary forcings. The latter concept has recently gained support from a growing amount of evidence. In this work, we provide an overview of the many empirical facts that would support a planetary hypothesis of the variability of solar activity and emphasize their importance for climate research. We show that the frequencies produced by the complex interactions of all of the planets are coherent with the major solar activity and climate cycles, from monthly to multimillennial timescales, including the well-known Schwabe 11-year solar cycle. We provide some persuasive theoretical and empirical support for the planetary hypothesis of solar and climate variability. Full article

The aims of this study are to assess the impacts of accelerated climate change on summer maximum temperatures since the early 1990s in the Australian city of Sydney’s eastern coastal and western inland suburbs. Western Sydney currently experiences far more intense summer (December–March) heat waves than coastal Sydney, with maximum temperatures exceeding those of coastal Sydney by up to 10 °C. Aside from increased bushfire danger, extreme temperature days pose health and socio-economic threats to western Sydney. Permutation tests of consecutive summer periods, 1962–1991 and 1992–2021, are employed to determine the differential climate change impacts on maximum summer temperatures at two locations: Sydney and Richmond, representative of eastern and western Sydney, respectively. Attribution of observed maximum summer temperature trends in Sydney and Richmond was performed using machine learning techniques applied to known Australian region oceanic and atmospheric climate drivers. It was found that there is a marked disparity in the percentage of summer days above the 95th percentile during the accelerated climate change period (1992–2021) between Richmond (+35%) and Sydney (−24%), relative to 1962–1991. The climate drivers detected as attributes were similar in both Sydney and Richmond, but, unsurprisingly, Sydney was more affected than Richmond by the oceanic climate drivers. Full article

In the present work, we investigate the solar radiation climate of Saudi Arabia, using solar radiation data from 43 sites in the country covering the period 2013–2021. These data include hourly values of global, G, and diffuse, G_d, horizontal irradiances from which the direct, G_b, horizontal irradiance is estimated. The diffuse fraction, k_d; the direct-beam fraction, k_b; and the ratio k_e = G_d/G_b, are used in the analysis. Solar maps of the annual mean G, G_d, k_d, k_b, and k_e are prepared for Saudi Arabia under all- and clear-sky conditions, which show interesting but explainable patterns. Additionally, the intra-annual and seasonal variabilities of these parameters are presented, and regression equations are provided. We find that G_b has a negative linear relationship with k_d; the same applies to G with respect to k_d or the latitude, φ, of the site. It is shown that k_d and k_b can reflect the scattering and absorption effects of the atmosphere on solar radiation, respectively; therefore, they can be used as atmospheric scattering and absorption indices. Part of the analysis considers the defined solar energy zones in Saudi Arabia. Full article