Future Drought Research Articles

Identification and Analysis of the MIR399 Gene Family in Grapevine Reveal Their Potential Functions in Abiotic Stress.

MiR399 plays an important role in plant growth and development. The objective of the present study was to elucidate the evolutionary characteristics of the MIR399 gene family in grapevine and investigate its role in stress response. To comprehensively investigate the functions of miR399 in grapevine, nine members of the Vvi-MIR399 family were identified based on the genome, using a miRBase database search, located on four chromosomes (Chr 2, Chr 10, Chr 15, and Chr 16). The lengths of the Vvi-miR399 precursor sequences ranged from 82 to 122 nt and they formed stable stem-loop structures, indicating that they could produce microRNAs (miRNAs). Furthermore, our results suggested that the 2 to 20 nt region of miR399 mature sequences were relatively conserved among family members. Phylogenetic analysis revealed that the Vvi-MIR399 members of dicots (Arabidopsis, tomato, and sweet orange) and monocots (rice and grapevine) could be divided into three clades, and most of the Vvi-MIR399s were closely related to sweet orange in dicots. Promoter analysis of Vvi-MIR399s showed that the majority of the predicted cis-elements were related to stress response. A total of 66.7% (6/9) of the Vvi-MIR399 promoters harbored drought, GA, and SA response elements, and 44.4% (4/9) of the Vvi-MIRR399 promoters also presented elements involved in ABA and MeJA response. The expression trend of Vvi-MIR399s was consistent in different tissues, with the lowest expression level in mature and young fruits and the highest expression level in stems and young leaves. However, nine Vvi-MIR399s and four target genes showed different expression patterns when exposed to low light, high light, heat, cold, drought, and salt stress. Interestingly, a putative target of Vvi-MIR399 targeted multiple genes; for example, seven Vvi-MIR399s simultaneously targeted VIT_213s0067g03280.1. Furthermore, overexpression of Vvi_MIR399e and Vvi_MIR399f in Arabidopsis enhanced tolerance to drought compared with wild-type (WT). In contrast, the survival rate of Vvi_MIR399d-overexpressed plants were zero after drought stress. In conclusion, Vvi-MIR399e and Vvi-MIR399f, which are related to drought tolerance in grapevine, provide candidate genes for future drought resistance breeding.

Past and Projected Future Droughts in the Upper Colorado River Basin

AbstractDrought has affected much of the western United States since about the year 2000, including the Upper Colorado River Basin (UCRB). Using a time series of UCRB streamflow derived from a tree‐ring based reconstruction of UCRB streamflow for the years 1 CE through 1905 CE, together with naturalized UCRB streamflow values for 1906 CE through 2021 CE, we identify 51 drought events, including the 2000–2021 drought. Although the recent 2000–2021 drought has been relatively severe, it is not the most severe of the UCRB drought events we identified. Results also indicate that natural variability combined with projected climate warming can result in UCRB drought events that are more severe than any drought since 1 CE.

Chronic drought decreased organic carbon content in topsoil greater than intense drought across grasslands in Northern China

Grasslands are expected to experience extreme climatic events such as extreme drought due to rising global temperatures. However, we still lack evidence of how extreme drought influence soil organic carbon (SOC) content in grassland ecosystems. We experimentally imposed extreme drought in two ways – chronic drought (66 % reduction in precipitation from May to August) and intense drought (100 % reduction in precipitation from June to July) to measure the effects of these two drought types on (SOC) content across six grassland sites that spanning desert steppe, typical steppe and meadow steppe in northern China. The experiment followed a randomized complete block design with six replicates of each treatment at each site. Our results showed that both chronic and intense drought decreased SOC content in the topsoil (0–10 cm) and the loss was higher in arid grasslands (desert steppe and typical steppe). Chronic drought decreased SOC content more than intense drought, with the effect again being strongest in arid grasslands. Furthermore, the response of SOC content to extreme drought was linked with the response of net primary productivity. Specifically, the response of SOC content was negatively correlated with drought sensitivity of above-ground net primary productivity (ANPP) but positively correlated with drought sensitivity of belowground NPP (BNPP). Overall, our results suggest that shifts in grassland SOC content with future drought will depend on the types of drought as well as the productivity responses and local climatic conditions such as precipitation, temperature, and aridity. The differential extreme drought impacts described here may facilitate predictions of climate change impacts on ecosystem carbon cycling.

Save or spend? Diverging water‐use strategies of grasses and encroaching clonal shrubs

Abstract Shrub encroachment is one of the primary threats to mesic grasslands around the world. This dramatic shift in plant cover has the potential to alter ecosystem‐scale water budgets and responses to novel rainfall regimes. Understanding divergent water‐use strategies among encroaching shrubs and the grasses they replace is critical for predicting shifts in ecosystem‐scale water dynamics as a result of shrub encroachment, particularly if drought events become more frequent and/or severe in the future. In this study, we assessed how water‐use traits of a rapidly encroaching clonal shrub (Cornus drummondii) and a dominant C4 grass (Andropogon gerardii) impact responses to changes in water availability in tallgrass prairie. We assessed intra‐annual change in depth of water uptake, turgor loss point and stomatal regulation in each species. Sampling took place at Konza Prairie Biological Station (northeastern KS, USA) during the 2021 and 2022 growing seasons. Cornus drummondii shifted from shallow to deep soil water sources across the 2021 and 2022 growing seasons. This plasticity in depth of water uptake facilitated a ‘wasteful’ water‐use strategy in C. drummondii, where stomatal conductance and transpiration rates continued to increase even when no further gain in photosynthetic rate occurred. A. gerardii photosynthetic rates and stomatal conductance were more variable through time and were more responsive to changes in leaf water potential than C. drummondii. However, intra‐annual adjustment of turgor loss point was more pronounced in C. drummondii (ΔπTLP = −0.48 MPa ± 0.15 SD) than in A. gerardii (ΔπTLP = −0.29 MPa ± 0.19 SD). Synthesis. These results suggest that C. drummondii is highly resilient to changes in water availability in surface soils and will likely remain unaffected by future droughts unless they are severe enough to reduce the availability of deep soil water. Given that clonal shrubs are key invaders of grasslands world‐wide, increased leaf‐level water loss is expected to accelerate ecosystem‐level drying as clonal shrub encroachment proceeds in mesic grasslands.

Xylem plasticity of root, stem, and branch in Cunninghamia lanceolata under drought stress: implications for whole-plant hydraulic integrity.

A better understanding of xylem hydraulic characteristics in trees is critical to elucidate the mechanisms of forest decline and tree mortality from water deficit. As well as temperate forests and forests growing in arid regions, subtropical and tropical forests are also predicted to experience an increased frequency and intensity of climate change-induced drought in the near future. In this study, 1-year-old Cunninghamia lanceolata seedlings (a typical subtropical species in southern China) were selected for a continuous controlled drought pot experiment of 45 days duration. The experimental treatments were non-drought (control), light drought, moderate drought and severe drought stress, which were 80%, 60%, 50%, and 40%, respectively of soil field maximum moisture capacity. The hydraulic conductivity, specific conductivity and water potential of roots, stems, and branches of C. lanceolata all decreased with the prolonging of drought in the different drought intensities. The relative decrease in these hydraulic values were greater in roots than in stems and branches, indicating that roots are more sensitive to drought. Root tracheid diameters normally reduce to ensure security of water transport with prolonged drought, whilst the tracheid diameters of stems and branches expand initially to ensure water transport and then decrease to reduce the risk of embolism with continuing drought duration. The pit membrane diameter of roots, stems and branches generally increased to different extents during the 15-45 days drought duration, which is conducive to enhanced radial water transport ability. The tracheid density and pit density of stems generally decreased during drought stress, which decreased water transport efficiency and increased embolism occurrence. Correlation analysis indicated that anatomical plasticity greatly influenced the hydraulic properties, whilst the relationships varied among different organs. In roots, tracheid diameter decreased and tracheid density increased to enhance water transport security; stems and branches may increase tracheid diameter and pit membrane diameter to increase hydraulic conductivity ability, but may increase the occurrence of xylem embolism. In summary, under drought stress, the xylem anatomical characteristics of C. lanceolata organs were highly plastic to regulate water transport vertically and radially to maintain the trade-off between hydraulic conductivity efficiency and safety.

Analysis of Forest Inventory Data Shows Disparity in Tree Mortality and Resistance in Texas National Forests

Abstract In 2011, the forestlands of Texas were affected by one of the most severe droughts in the state’s history, killing an estimated 65 million trees in the East Texas region. This study uses USDA Forest Service Forest Inventory and Analysis data and a standardized precipitation-evapotranspiration index to estimate major tree species responses to the 2011 drought in Texas’ four national forests. We used an analysis of variance and a linear mixed-effect model to evaluate factors contributing to tree mortality and growth. We found that tree mortality rates varied greatly during the drought period relative to predrought levels; higher stand age, higher stand density, and higher mean summer temperature contributed to tree mortality volume. Study Implications: Drought is a recurring disturbance agent and is likely to continue to increase in frequency and severity in the future. We provide an understanding of an exceptional drought as a disturbance agent and its impacts on tree mortality and resistance. The effects of the 2011 drought on national forests in Texas have not previously been evaluated. Texas’ national forests represent over 256,975 ha (635,000 ac) in the state’s eastern region and nearly 10% of all public land in Texas. Our results are useful to decision makers in developing strategies and protecting forestlands in the face of potential future droughts.

Arbuscular mycorrhizal fungal contribution towards plant resilience to drought conditions.

Climate changes cause altering rainfall patterns resulting in an increase in drought occurrences globally. These events are disrupting plants and agricultural productivity. To evade droughts, plants try to adapt and modify in the best capacities possible. The plants have adapted by structurally modifying roots, stems, and leaves, as well as modifying functions. Lately, the association of microbial communities with plants has also been proven to be an important factor in aiding resilience. The fungal representatives of the microbial community also help safeguard the plants against drought. We discuss how these fungi associate with plants and contribute to evading drought stress. We specifically focus on Arbuscular mycorrhizal fungi (AMF) mediated mechanisms involving antioxidant defenses, phytohormone mediations, osmotic adjustments, proline expressions, fungal water absorption and transport, morphological modifications, and photosynthesis. We believe understanding the mechanisms would help us to optimize the use of fungi in agricultural practices. That way we could better prepare the plants for the anticipated future drought events.

Divergent future drought projections in UK river flows and groundwater levels

Abstract. Hydrological drought is a serious issue globally, which is likely to be amplified by 21st century climate change. In the UK, the impacts of changes in river flow and groundwater drought severity in a future of climate change and higher water demand are potentially severe. Recent publication of a new nationally consistent set of river flow and groundwater level projections (the eFLaG dataset), based on state-of-the-art UKCP18 climate projections, offers a unique opportunity to quantitatively assess future UK hydrological drought susceptibility. The dataset includes a transient, multi-model ensemble of hydrological projections driven by a single regional climate model (RCM), with a 12-member perturbed-parameter ensemble, for 200 catchments and 54 boreholes spanning a period from 1961 to 2080. Assessment of a baseline period (1989–2018) shows that the RCM-driven projections adequately reproduce observed river flow and groundwater level regimes, improving our confidence in using these models for assessment of future drought. Across all hydrological models and most catchments, future low river flows are projected to decline consistently out to 2080. Drought durations, intensities and severities are all projected to increase in most (over 90 %, pooling across different drought characteristics) UK catchments. However, the trajectory of low groundwater levels and groundwater drought characteristics diverges from that of river flows. Whilst groundwater levels at most (> 85 %) boreholes are projected to decline (consistent with river flows), these declines are relatively modest (< 10 % reduction) in transient low groundwater levels by 2080, and, in fact, six show moderate increases. Groundwater drought characteristics in the far future (2050–2079) are often similar to those of the baseline (1989–2018), with only 33 % of boreholes showing an increase (towards worsening drought) of more than 10 % for drought severity (48 % of boreholes for drought intensity). Interestingly, for some boreholes, droughts are projected to be more prolonged and severe in the near future (2020–2049) before returning to shorter durations and lower severity in the far future. A number of explanatory factors for this divergence between river flow and groundwater are discussed. The sensitivity to seasonal changes in precipitation and potential evapotranspiration is proposed as a principal driver of divergence because low river flows are more influenced by shorter-term rainfall deficits in the summer half-year, whilst groundwater drought appears to be offset somewhat by the wetter winter signal in the RCM projections. Our results have important implications for water management, demonstrating a widespread increase in river flow drought severity and diminishing low flows that could have profound societal and environmental impacts unless mitigated. Furthermore, the divergence in projections of drought in river flows and groundwater levels brings into question the balance between surface and subsurface water resources. The projected contrast in fortunes of surface and subsurface water resources identified for the UK may be replicated in other parts of the world where climate projections suggest a shift towards drier summers and wetter winters.

Estimación de la evapotranspiración a partir de imágenes de alta resolución de VANT para sistemas de riego en arrozales de la costa norte de Perú

In view of the growing scarcity of water for agriculture, the increase in food demand and future drought scenarios posed by climate change, it is essential to design new technologies that contribute to lower water consumption. In this research, high-resolution images have been used to estimate evapotranspiration in rice fields by applying the METRICTM (Mapping Evapotranspiration at High Resolution using Internalized Calibration) energy balance model. For this purpose, 5900 m2 of crop were monitored under continuous flood irrigation (CF) and 2600 m2 under alternate wetting and drying irrigation (AWD), in addition to some plots with lateral filtration. Ten flights were conducted between tillering and flowering phases, five flights with a Matrice 210 UAV equipped with a Parrot Sequoia multispectral camera, and five flights with a Matrice 300 RTK equipped with a H20T thermal camera. Field data were collected from vegetation indices (NDVI and LAI), and readings from a radiometer, to adjust information from multispectral and thermal images, respectively, and to obtain the components of the surface energy balance. Mean values for crop evapotranspiration (ETc) of 6.34 ± 1.49 and 5.84 ± 0.41 mm d-1 were obtained for IC irrigation and AWD irrigation, respectively, obtaining a water saving of 42% with a yield reduction of 14%, providing a guide for proper irrigation management, however, it is suggested to use the model to optimize yield by obtaining critical thresholds for optimal application of AWD in the face of water resource scarcity.

Critical thresholds for nonlinear responses of ecosystem water use efficiency to drought

Climate change is expected to lead to greater variability in precipitation and drought in different regions. However, the responses of ecosystem carbon and water cycles (i.e., water use efficiency, WUE) to different levels of drought stress are not fully understood. Here, we examined the relationship between WUE and precipitation anomalies and identified the critical drought threshold (DrCW) above which WUE showed substantial decrease. The results revealed that 85.56 % of the study area had nonlinear WUE responses to drought stress; that is, the WUE decreased sustainably and steeply when the precipitation deficit exceeded the DrCW. DrCW indicates inflection points for changing ecosystem responses from relatively resistant to vulnerable to drought stress, thus providing an instructive early warning for intensifying suppressive impacts on vegetation growth. Additionally, DrCW varies across aridity gradients and among vegetation types. Based on the DrCW at the pixel level, the future eco-drought is projected to increase in >67 % of the study area under both the SSP2&RCP4.5 and SSP5&RCP8.5 scenarios by the end of the 21st century. Our study elucidates the response of the ecosystem function to drought and supports the development of accurate ecosystem adaptation policies for future drought stress.

Modeling future (2021–2050) meteorological drought characteristics using CMIP6 climate scenarios in the Western Cape Province, South Africa

Consistent drought modelling under plausible shared socioeconomic–representative concentration pathways (SSP–RCPs) are crucial for effectively managing future drought risk in agricultural environments. The Western Cape (WC) is one of South Africa’s main agro-based provinces and faces a mounting threat of water insecurity due to recurrent drought. The objective of this study was to predict meteorological drought hazard for 2021–2050 based on three CMIP6 scenarios: SSP5–8.5, SSP2–4.5 and SSP1–2.6. Precipitation simulations generated by the sixth version of Model for Interdisciplinary Research on Climate (MIROC6) under the SSP5–8.5, SSP2–4.5 and SSP1–2.6 scenarios were used from fifteen stations across the six AEZs of the WC province. The Standardised Precipitation Index (SPI) was computed at 12-month timescales. Trend analysis of precipitation datasets and the SPI-values were done at p < 0.05 using the Mann–Kendall (M–K) test. The findings revealed negative precipitation trends of − 7.6 mm/year in Ceres, while positive trends of 0.3 mm/year were observed in Malmesbury. These findings indicate an improvement from − 7.8 and − 6.4 mm/year in the same regions, respectively, compared to historical trends observed between 1980 and 2020. The results suggest that in 2042 and 2044, Bredasdorp will experience − 2 < SPI < − 1.5 under the SSP2–4.5 scenarios, while Matroosberg in 2038 under the SSP5–8.5 will experience SPI > − 2. The findings of this study will assist in the development of proactive planning and implementation of drought mitigation strategies and policies aimed at reducing water insecurity in AEZs.

Season of drought affects growth, but not nonstructural carbohydrates dynamics, in Pinus taeda saplings.

In temperate evergreen conifers, growth occurs mostly in summer but photosynthesis precedes year-round; thus, nonstructural carbohydrates (NSC) increase in winter but decrease in summer. Given that mild drought reduces growth but not photosynthesis, a drought in summer should increase NSCs more than one in winter. However, the active regulation hypothesis suggests that to increase future drought resilience, plants might downregulate growth to increase NSCs after a winter drought even if NSCs do not increase during the drought. To test if so, potted Pinus taeda saplings (age $< 1$ yr) were subjected to six-month droughts in a greenhouse with one treatment receiving drought during winter (Sep-Mar), and another during summer (Mar-Sep). Both treatments were compared to a control. To measure dry biomass and NSCs, we harvested plants monthly following each drought, while to assess changes in growth rates, we measured height and diameter monthly. While we observed seasonal variation and an overall increase during the study, we found no drought-related changes in NSC dynamics; however, drought did reduce growth. Furthermore, drought in winter did reduce growth during the following summer, but the reduction was less than for a drought in summer. We conclude that the effect of drought on NSCs was too small to detect in our plants. While better control of soil water would have reduced a major source of uncertainty, plants with larger NSC reserves or more intense stress would also yield easier-to-detect effects. Although not definitive, our results suggest that water stress does not lead to dramatic changes in seasonal NSC dynamics in its aftermath, despite what one might expect under the active regulation hypothesis.

Understanding climate change impacts on drought in China over the 21st century: a multi-model assessment from CMIP6

The future state of drought in China under climate change remains uncertain. This study investigates drought events, focusing on the region of China, using simulations from five global climate models (GCMs) under three Shared Socioeconomic Pathways (SSP1-2.6, SSP3-7.0, and SSP5-8.5) participating in the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP3b). The daily Standardized Precipitation Evapotranspiration Index (SPEI) is employed to analyze drought severity, duration, and frequency over three future periods. Evaluation of the GCMs’ simulations against observational data indicates their effectiveness in capturing historical climatic change across China. The rapid increase in CO2 concentration under high-emission scenarios in the mid- and late-future century (2040–2070 and 2071–2100) substantially influences vegetation behavior via regulation on leaf stomata and canopy structure. This regulation decelerates the increase in potential evapotranspiration, thereby mitigating the sharp rise in future drought occurrences in China. These findings offer valuable insights for policymakers and stakeholders to develop strategies and measures for mitigating and adapting to future drought conditions in China.

Drought projections for the NW Iberian Peninsula under climate change

Drought can be considered an atmospheric condition, which rapidly goes beyond to affect multiple fields of the environment and human activities. The persistence of these atmospheric conditions can affect the recharge of surface and groundwater bodies due to a decrease in the volume of runoff and seepage, thus affecting human and environmental activities. In this context, the main aim of this work is to characterize the occurrence and variability of future droughts in Galicia over the twenty-first century. The methodology followed is based on the calculation and analysis of the Standardized Precipitation Index (SPI) in three-time scales (3, 6, and 12 months), using daily outputs of precipitation data from one RCM provided by the EURO-CORDEX project for different periods (reference from 1971 to 2005, and future from 2025 to 2060 and 2061 to 2096) and scenarios (RCP 4.5 and RCP 8.5). Using SPI-3, SPI-6, and SPI-12 projections, drought trends and potential changes in their characteristics were explored under RCP 4.5 and RCP 8.5 scenarios. In both scenarios, throughout the twenty-first century, a decreasing trend in SPI indicates an intensification of drought conditions over Galicia. Moreover, at the beginning of the century, under RCP 4.5, drought events will increase and will be slightly more intense but less persistent, while under RCP 8.5, the number of events will be almost the same, but shorter and less severe. Toward the end of the century, drought events are expected to be more numerous, less durable, and more intense under both scenarios.

Simulating the effects of optimizing sowing date and variety shift on maize production at finer scale in northeast China under future climate.

Global warming and the rising occurrences of climate extremes have become formidable challenges for maize production in northeast China. The optimization of sowing date and variety choice stand out as two economic approaches for maize to enhance its resilience to climate change. Nevertheless, assessment of the potential of optimizing sowing date and variety shift on maize yield at finer scale remains underexamined. This study investigated the implications of optimizing sowing date and implementing variety shift on maize yield from a regional perspective. Compared to the reference period (1986-2005), climate change would decrease by 11.5-34.6% (the range describes the differences among climate scenarios and agro-ecological regions) maize yield in the 2050s (2040-2059) if no adaption measure were to be implemented. The combined adaption (optimizing sowing date and variety shift) can improve maize yield by 38.8 ± 11.3%, 42.7 ± 9.7% and 33.9 ± 7.6% under the SSP1-2.6, SSP2-4.5 and SSP5-8.5 scenarios, respectively. The current sowing window typically falls within the projected optimal sowing window, defined as the period capable of achieving 90% of the maximum yield within the potential sowing window under future climate conditions. Consequently, the potential of the effect of optimizing sowing window on maize yield is limited. In contrast, variety shift results in higher yield improvement, as temperature rise creates favorable conditions for transplanting varieties with an extended growth period, particularly in high latitudes and mountainous regions. Under future climate, cumulative precipitation and compound drought and hot days during maize growing seasons are two key factors influencing maize production. The optimization of sowing date and variety choice can improve maize yield in northeast China. In addition, maize production should consider varieties with longer growth period and drought and heat tolerance to adapt to climate change. © 2023 Society of Chemical Industry.

Fire regimes of the Southern Appalachians may radically shift under climate change

BackgroundIncreased drought due to climate change will alter fire regimes in mesic forested landscapes where fuel moisture typically limits fire spread and where fuel loads are consistently high. These landscapes are often extensively modified by human land use change and management. We forecast the influence of varying climate scenarios on potential shifts in the wildfire regime across the mesic forests of the Southern Appalachians. This area has a long history of fire exclusion, land use change, and an expanding wildland urban interface. We considered interactions among climate, vegetation, and anthropogenic influences to forecast future fire regimes and changes to the forest structure. We used climate scenarios representing divergent drought patterns (overall drought trend and interannual variability) within a process-based fire model that captures the influence of climate, fuels, and fire ignition on wildfire patterns and suppression.ResultsCompared to simulations using historical climate (1972–2018), future total burned area (2020–2100: 782,302.7 (716,655.0–847,950.3) ha) increased by 42.3% under high drought variability (1,134,888.4 (1,067,437.2–1,202,339.6) ha), 104.8% under a substantial increase in drought trend (1,602,085.7 (1,511,837.5–1,692,334.0) ha), and 484.7% when combined (4,573,925.0 (4,434,910.5–4,712,939.5) ha). Landscape patterns of fire exclusion and suppression drove the spatial variability of fire return intervals (FRI). Our projections indicate wide spatial variability in future fire regimes with some areas experiencing multiple fires per decade while others experience no fire. More frequent fires corresponded with increased oak prevalence and a reduction in the biomass of mesic hardwoods and maple; however, mesic hardwoods remained prevalent under all fire intervals because of their contemporary dominance.ConclusionsOur study illustrates how future drought–fire–management interactions and a history of fire exclusion could alter future fire regimes and tree species composition. We find that increasing trends in drought magnitude and variability may increase wildfire activity, particularly in areas with minimal fire suppression. In ecosystems where fuel moisture (and not load) is the standard limitation to fire spread, increased pulses of drought may provide the conditions for more fire activity, regardless of effects on fuel loading. We conclude the effects of climate and human management will determine the novel conditions for both fire regime and ecosystem structure.

How will drought evolve in global arid zones under different future emission scenarios?

Study regionGlobal aridity zones. Study focusEvaluating drought under the impact of climate change is crucial for ensuring sustainable development and ecological security, especially in global arid zones where the environment is vulnerable to global warming. However, there are large uncertainties in evaluating the future drought risk of arid zones due to uncertainties within climate projections and the use drought-related indices that may not be appropriate for all assessments. Therefore, under the precondition of bias correction applied to CMIP6 data, the drought detection capability of drought indices calculated from multimodel ensemble was evaluated. Based on the drought index with the strongest detection capability and the Reliability-Resilience-Vulnerability (RRV) framework, the future drought risk in global arid zones were predicted. New hydrological insights for the regionAmong the drought indices calculated from CMIP6 historical simulations, SPEI offered the best representation of drought patterns. According to the CMIP6 future projections, SSP1–2.6 can effectively mitigate the impact of future drought risk compared with the historical period. In scenarios with higher emissions, the equatorial to northern latitude 30° region will experience more severe drought. For SSP5–8.5, the areas in the arid zones where drought risk deteriorates significantly are several times larger than in other scenarios. To mitigate drought risks, most nations should support a greener, low-emission approach in line with sustainable development goals, reducing the risk of drought-related damage.

Agricultural drought risk and local adaptation measures in the Upper Mun River Basin, Thailand

Northeast Thailand is one of the country's important agricultural regions. Yet, it is frequently grappled by droughts affecting crop production as most of the cultivation depends on rain-fed irrigation. This study employs a comprehensive framework for assessing the drought risk in the Mun River basin, including hazard, exposure, and vulnerability factors. Hazard is estimated using a multivariate approach considering drought duration and severity, while exposure and vulnerability are evaluated using eighteen proxy factors encompassing physical and socioeconomic aspects. Local adaptation measures adopted by farmers to cope with droughts are an integral part of the risk assessment framework. Factors are normalized to five equally spaced categories and are aggregated using weights obtained from AHP through a survey among 50 local experts. Further, an extensive survey was conducted among 122 farmers in two hotspots with high hazards but contrasting vulnerability to investigate adaptation practices. Experts in the region perceive a higher importance of adaptive capacity than drought susceptibility while defining vulnerability. The results show that people living in areas with high hazard levels and physical vulnerability also tend to have a higher adaptive capacity to manage water scarcity. Overall, 22% of the area is under high to very high drought risk. Specifically, 14% of the area in Nakhon Ratchasima, 15% in Buriram, 8% in Surin, and 19% in Si Sa Ket provinces have very high risk. Among two hotspots, Dan Khun Thot district farmers have diversified crops and practiced various adaptive measures to build their resilience against drought and have low vulnerability and risk. In contrast, adaptation measures are implemented to a far lesser extent in the Phlapphla Chai district and have high vulnerability and risk. The education level of farmers is found to be directly linked with the implementation of local adaptation measures. The disparity in the adaptive measures adopted in two districts highlights the significance of agricultural water management interventions. Access to climate information regarding droughts, building farm ponds, and crop management practices are the preferred adaptation measures taken by the farmers. The study recommends districts in each province identified as having high risk are prioritized and supported by the local government to improve farm-level water management practices and drought resilience. It is imperative as looming climate change will further exacerbate future droughts.

Multivariate Assessment of Groundwater Depletion and Recharge Prospect in a Sub-tropical Basin of Eastern India

Abstract The present study aims to highlight the groundwater-stress condition of the Quaternary 一 recent alluvial region escalated by anthropogenic extraction of water resources in the western Bengal Basin (Purba Bardhaman, West Bengal, India). With the rapid development of irrigation technology, high crop yield, water- consumed rice varieties, and high cropping intensity, the farmers of the river basin go to deeper underground aquifers (&amp;gt;180 m bgl) to extract water for summer rice (Boro) cultivation. In this study, the five semi-critical blocks (Mangolkote, Bhatai; Manteswai; Purbasthali II, and Memari II) of Purba Bardhaman district have experienced statistically significant pre-monsoon fall (0.404 m yr- 1 to 1.099 m yr-1) and post-monsoon fall of groundwater level from 0.486 m yr-1 to 2.214 m yr-1. Principal component analysis reflects that annual irrigation draft, annual replenishable groundwater unit, net groundwater availability, Boro rice cultivation area, area to be covered on each day irrigation for Boro, and daily pump discharge required for Boro irrigation are the key factors to escalate groundwater decline. This study reveals that Galsi II, Bardhaman I and II, Katwa I, and Purbasthali I blocks will experience a water-stress or groundwater drought in future. The model of groundwater recharge potential zone shows four principal categories of groundwater prospect area in the basin, viz., poor (0.08 %), moderate (5.78 %), good (68.96 %), and very good (25.18 %). These findings provide the relevant information for planners of groundwater resources to upscale groundwater management procedures and enhance the sustainability of agricultural systems in the study area.

Projection analysis of future drought characteristics in Upper Draa Catchment (Southern Morocco)

The consequences of global warming will aggravate the impacts of droughts. Future drought patterns are important for planning and policy formulation to mitigate the adverse effect of climate change. Consequently, this study aims at examining the projected the drought characteristics in seven meteorological stations in the Upper Draa Catchment (UDC) during the period from 1980 to 2016 using standardized precipitation index. The future climate scenarios were predicted by the model CNRM-ALADIN63 for three periods (2025–2049, 2050–2074, and 2075–2099). The changes were examined based on two Representative Concentration Pathways scenarios, namely: RCP4.5and RCP8.5. The findings indicated that increasingly extreme droughts are anticipated to occur during (2050-2074) followed by (2025-2049) than (2075-2099) under both scenarios. The results reveal a contrast in drought event frequency between historical data and projections with a noticeable variation of patterns of droughts characteristics across stations and time periods. This accentuates how urgent it is for the Upper Draa Catchment to implement proactive water resource management and adaptive strategies.