Recent Climate Research Articles

Risk analysis of mutual influence relationships among residents under rescue operations in long-term flooded areas

Recent climate change is expected to cause severe flood damage, and new flood countermeasures are urgently required. However, there is concern that the current capacity of rescue operations is limited in response to the increasing scale of flood damage. In future flood countermeasures, it will be necessary for the government not only to carry out rescue activities but also to demand a balance between self-help and public assistance, for example, by requesting residents to evacuate voluntarily. However, to expect a change in the attitude of the residents themselves, it is important to communicate the risk by presenting evidence for such a change. Therefore, in this study, problems related to the rescue of isolated residents in water rescue operations in long-term inundated areas and the effects on residents waiting for rescue were identified. Specifically, we conducted a rescue simulation using a multiagent system in an actual urban area that was expected to be flooded for a long period. We confirmed that boat rescue operations are subject to more restrictions than ground rescue operations and pose a significant risk to residents waiting for rescue operations. We observed a strong interrelationship between residents who shared limited rescue resources, and that the decisions of individual residents influenced each other's rescue time. These relationships have given rise to an ethical problem called rescue triage owing to the nature of boat rescue operations. This study does not aim to find a rescue policy or an efficient rescue operation but discusses risk management in rescue operations in a long-flooded area.

Examining the spatio-temporal relationship between LST, NDVI, NDBI and LULC change of Pachhua dun, Dehradun, Uttarakhand (India)

Recent climate change has had a negative impact on a wide range of human and natural systems, and it is clear that humans influence the climate. Because, as anthropogenic influence increases, the heat output from the land surface increases, speeding up the rate of climate change. In this regard, the use of RS and GIS techniques has provided various opportunities for research to examine these changes. The current analysis is based on the Landsat 1989, and 2020. Over the study period of 31 years, the built-up regions increased in size from 44.23 km2 to 154.56 km2. Whereas, the area covered by scrubland, water bodies, and vegetation cover has significantly decreased. The LST study further supports the outcome, showing that the mean and standard deviation increased from 14.81°C±1.32(1989) to 18.82°C±1.57(2020). The study also made an effort to examine how LULC affected LST; while vegetation cover has consistently helped to lower mean LST, built-up areas and scrubland are the main drivers of mean LST rise. The LST and NDBI revealed a positive correlation, while the NDVI/SLOPE and LST showed a negative correlation. Subsequently, the multiple linear regression (MLR) models concluded that the BUAs has evolved into a serious threat to the increase in LST, but increase in vegetation cover and SLOPE would result in slight decrease in LST. the study recommended that the government create policies that restrict future land encroachment and conversion, notably of forested area and water bodies, and make an immediate effort to increase the quantity and quality of urban green cover in the study area. So that we may, respectively, minimize the potential hazard posed by future LST rise and LULC change.

Electron Uptake from Solid Electrodes Regulates the More Efficient Conversion of CO2 to Polyhydroxybutyrate with Rhodobacter Spaeroides

The recent climate crisis has accelerated studies on mitigating the atmospheric CO2 level. Microbial electrosynthesis (MES) is highlighted as a promising strategy for CO2 conversion to useful chemicals. This study examined electrode-driven polyhydroxybutyrate (PHB) production from CO2 in Rhodobacter sphaeroides. The electron uptake and regulation of metabolic pathways differed in electrode-associated and suspended R. sphaeroides cells. The electrode-associated cells produced PHB at concentrations reaching 23.50 ± 2.8% of the dry cell weight (DCW). These results reveal a means for CO2 upcycling to polymeric substances and provide novel insights into the genetic regulation of electrode-associated cells in MES.

Recent changes in forest structure and growth at the alpine‐treeline ecotone in the Rocky and Columbia Mountains of central British Columbia, Canada

AbstractAimGlobally, forests at the alpine‐treeline ecotone (ATE) are considered sensitive to warming temperatures; however, responses to recent climate change show high variability and many underlying processes remain unclear. This study aims to provide further insight into possible ATE forest responses to climate change by examining spatiotemporal patterns in recent tree regeneration and growth responses to climate across treeline forms.LocationThis study is situated at the ATE in the Rocky Mountain and Columbia Mountain ranges in central British Columbia, Canada.TaxonGymnosperms – subalpine fir (Abies lasiocarpa Hooker (Nutall)).MethodsWe collected tree and stand data from 48 plots across five study sites. Plots were distributed across three treeline stand types: (i) islands; (ii) abrupt; and (iii) fringes of regeneration adjacent to tree islands. We used a dendrochronological approach to analyse the ages of recently established trees in fringe stand types, detect long‐term trends in annual tree growth and quantify climate‐growth relationships.ResultsSeedling recruitment adjacent to tree islands occurred over a period of approximately 40 years (1960–2000), with two regeneration “pulses” in the late 1970s and 1980s. Abrupt and fringe trees showed a similar age structure and annual radial growth has increased in most trees over the past 30 years. Across the study region and stand types, summer temperature has the strongest influence on radial growth. Over the past 70 years, growth in tree islands has become increasingly correlated with growing season temperature variables.Main ConclusionsForest growth and structure have changed in coherent spatial and temporal patterns over recent decades at the ATE in central BC. Projections for sustained warming in this region will likely result in increased tree growth and potential continued expansion of forests into untreed areas below the treeline. These changes will have implications for hydrological regimes, wildlife habitat and carbon sequestration.

High-Resolution Bioclimatic Variables in Mt. Jirisan and Hallasan under Climate Change Scenario

Many endemic and rare species live in Korea’s subalpine zone, but there have been many research results showing that alpine creatures are disappearing due to recent climate change. Therefore, in this study, bioclimatic variables with 100 m resolution were created for Mt. Jirisan and Mt. Hallasan, representative mountainous regions in Korea. Nineteen high-resolution bioclimatic variables were created for the current and 4 future periods, and the generated data is believed to represent topographical characteristics well. This data is expected to be useful to predict potential habitats through species distribution modeling and the impact of climate change on organisms limited to alpine regions.

Estimating Riparian Vegetation Volume in the River by 3D Point Cloud from UAV Imagery and Alpha Shape

This study employs technology that has many different applications, including flood management, flood level control, and identification of vegetation type by patch size. Recent climate change, characterized by severe droughts and floods, intensifies riparian vegetation growth, demanding accurate environmental data. Traditional methods for analyzing vegetation in rivers involve on-site measurements or estimating the growth phase of the vegetation; however, these methods have limitations. Unmanned aerial vehicles (UAVs) and ground laser scanning, meanwhile, offer cost-effective, versatile solutions. This study uses UAVs to generate 3D riparian vegetation point clouds, employing the alpha shape technique. Performance was evaluated by analyzing the estimated volume results, considering the influence of the alpha radius. Results are most significant with an alpha radius of 0.75. This technology benefits river management by addressing vegetation volume, scale, flood control, and identification of vegetation type.

A species' response to spatial climatic variation does not predict its response to climate change.

The dominant paradigm for assessing ecological responses to climate change assumes that future states of individuals and populations can be predicted by current, species-wide performance variation across spatial climatic gradients. However, if the fates of ecological systems are better predicted by past responses to in situ climatic variation through time, this current analytical paradigm may be severely misleading. Empirically testing whether spatial or temporal climate responses better predict how species respond to climate change has been elusive, largely due to restrictive data requirements. Here, we leverage a newly collected network of ponderosa pine tree-ring time series to test whether statistically inferred responses to spatial versus temporal climatic variation better predict how trees have responded to recent climate change. When compared to observed tree growth responses to climate change since 1980, predictions derived from spatial climatic variation were wrong in both magnitude and direction. This was not the case for predictions derived from climatic variation through time, which were able to replicate observed responses well. Future climate scenarios through the end of the 21st century exacerbated these disparities. These results suggest that the currently dominant paradigm of forecasting the ecological impacts of climate change based on spatial climatic variation may be severely misleading over decadal to centennial timescales.

Ultra-high-resolution reflected-light imaging for dendrochronology

Dendroclimatic reconstructions play a key role in contextualizing recent climate change by improving our understanding of past climate variability. The Blue Intensity (BI) measurement technique is gaining prominence as a more accessible alternative to X-ray densitometry for producing climatically highly-sensitive tree-ring predictors. Nevertheless, accurately representing low-frequency trends and high-frequency extremes using scanner-based BI remains a challenge due to color biases and resolution limitations. Herein we introduce several methodological advances in sample surfacing, imaging, and image processing which yield measurement series analogous to BI from ultra-high-resolution (UHR; ∼74 700 dpi) images. Such series capture changes in tree-ring anatomical density by representing wood anatomical structure using binary (i.e., black-white) segmentation of sample images. We refer to this novel technique as Binary Surface Intensity (BSI). By utilizing a UHR system and entirely eliminating color and light intensity as variables, the most substantial drawbacks of scanner BI (i.e., discoloration and resolution biases) are bypassed, resulting in more accurate representations of low-frequency climatic trends and high-frequency extremes. Comparisons of several chronologies developed with the BSI and BI techniques, including a multiparameter dataset from Björklund et al. (2019), showed that BSI datasets outperform BI in terms of common signal (r-bar), but also contain strong climatic signals that can exceed those obtained from BI and X-ray density, and even match density datasets based on quantitative wood anatomy. However, measurement software advancements are still required to unlock the full potential of tree-ring parameters produced using the BSI technique. Ongoing development of this new technique will not only aid the attainment of long unbiased chronologies by overcoming color biases and resolution limitations, but also holds promise for unlocking UHR analyses of surface anatomical (sQWA) parameter datasets from reflected-light images. These advances will lead to more accurate tree-ring-based paleoclimatic reconstructions and could also serve a wider range of dendrochronological applications.

Albedo on a glacial foreland at ground level and landscape scale driven by vegetation-substrate patterns

Recent anthropogenic climate change has caused both glacial retreat and increased vegetative growth on Arctic and subarctic tundra landscapes resulting in changing albedo and energy budgets. Glacial forelands are topographically and ecologically heterogeneous landscapes comprising ice-contact and outwash deposits subject to primary succession. The most recent moraines on the foreland of the Skaftafellsjökull in southern Iceland are mostly unvegetated, but vegetation cover increases with the age in a general sense. Vegetated outwash channel terraces occur between the moraines, and a broad vegetated outwash plain occurs distal to the oldest moraine. Variations in albedo were measured at ground level to determine the specific role of vegetation types and varying substrates. Albedo and coverage by major plant groups were measured along transects established on moraines ranging in age from 20 to 130 years and the terrace of one outwash channel and three locations on the outwash plain. Total vegetation cover and coverage by mosses increases on the glacial moraines largely as a function of time but is subject to strong aspect effects. Total vegetation cover and moss cover are highest on outwash deposits, possibly due to a sheltered aspect and greater uniformity of the outwash surface. Measured albedo exhibits a modest positive correlation with total vegetation cover and a modest negative correlation with rock and soil exposure. The strongest positive correlation was found between albedo and moss cover. The differences in brightness between moraines and outwash deposits are evident visually at the landscape scale on satellite photographs and quantifiable by image-processing software.

Impact of recent and future climate change on vectorborne diseases: viruses analyses

Climate directly impacts health through climatic extremes, air quality, sea-level rise, and multifaceted influences on food production systems and water resources. Climate also affects infectious diseases, which have played a significant role in human history, impacting the rise and fall of civilizations and facilitating the conquest of new territories. This review highlights significant regional changes in vector and pathogen distribution , changes that have been anticipated by scientists worldwide . Further future changes are likely if we fail to mitigate and adapt to climate change. Many key factors affect the spread and severity of human diseases, including mobility of people , animals , and goods; control measures in place; availability of effective drugs; quality of public health services; human behavior; and political stability and conflicts.

Spatial and temporal variability in Holocene trough-fill sediments, King Haakon Trough System, sub-Antarctic South Georgia

The climate in the South Atlantic sector of the sub-Antarctic, and therefore on and around the island of South Georgia, is dependent on the Southern Hemisphere Westerlies (SHW) and the Antarctic Circumpolar Current (ACC). The SHW and the ACC, in turn, are strongly controlled by climate variability in the Southern Hemisphere. Accordingly, thick sediment sequences in the troughs across South Georgia's continental shelf serve as valuable archives for past climate variations in the Southern Ocean. Since Holocene climate fluctuations led to only minimal oscillations in glacier margin positions within the fjords, the entire shelf was exposed to dynamic ocean currents since at least 10 ka BP. Its depositional systems are therefore a suitable target for the reconstruction of Holocene dynamics of both the SHW and the ACC. Sub-bottom profiler data and radiocarbon ages from four gravity cores from the south-western South Georgia continental shelf provide evidence for a complex interplay between island run-off and ocean currents intruding into a unique cross-shelf trough system during the last ∼10 ka. The data reveal several prominent changes in sediment and Holocene climate dynamics, the most significant occurring between 8 and 7.7 cal ka BP and between 2.6 and 2.2 cal ka BP. Both of these time periods represent transitions from warmer to cooler and windier conditions in South Georgia and the Southern Hemisphere. Our record from the King Haakon Trough System is the first highly resolved Holocene archive from the marine realm on the south-western South Georgia continental shelf and suggests several large-scale Southern Hemisphere climate changes during the mid-to late Holocene.

LAND COVERAGE ANALYSIS OF PAKISTAN USING SATELLITE IMAGERY

Abstract. Pakistan has a unique landscape geographically due to its strategic geo-political importance. It has played a vital role in global climate and politics. There are various semantic segmentation studies performed on remote sensing high-resolution imagery of various urban and rural areas into major classes of buildings, vegetation, water, and roads. These analyses have supported the land coverage study, which can facilitate urban infrastructure management, forestry, disaster management, and climate challenges. Recent climate reports have confirmed the importance of these studies, especially for Pakistan. It’s a critical location for the global south to observe the climate catastrophe. This research will focus on three major cities of Islamabad, Karachi, and Quetta and semantically segment the satellite imagery to study the land coverage. Our research contributes the dataset from major cities of Pakistan and compare the performance of state-of-the-art semantic segmentation networks to evaluate the dataset. Benchmark can help in selecting a highly effective deep learning network and generalizing those networks on our prepared dataset. Dataset can be downloaded from here: https://github.com/Abdullah-Sabir/Pakistan-Land-Coverage-Analysis-Dataset

Mid-late holocene climatic reconstruction using core sediments from Khajjiar lake, Himachal Pradesh, India

We present results of our investigations on 7.65 m long core sediments from the Khajjiar lake, Himachal Pradesh, aimed at reconstructing palaeoclimate variability in the climatically sensitive region affected by both ISM (Indian Summer Monsoon) and IWM (Indian Winter Monsoon). Based on the multi-proxy approach, including organic geochemistry (carbon isotopes), magnetic susceptibility as primary proxies and inorganic geochemistry (major oxides) with grain size analysis as secondary proxies, climate of the mid-late Holocene (∼4600 yr) has been established on centennial to millennial scale. The chronology of the sediments is constrained by five AMS radiocarbon dates. The sedimentological data reveal variations in sediment grain size related to palaeo-precipitation. The first high resolution multi-proxy record from the Khajjiar lake core indicates less humid conditions during ∼4600–4185 cal yr BP except an extreme peak of dry and arid climate at around ∼4370 cal yr BP. Intensified monsoon with more wet and humid conditions has been interpreted during ∼4185–3790 cal yr BP. ∼3790–3300 cal yr BP, ∼2845–2115 and ∼1555–405 cal yr BP, and ∼2990–2845 cal yr BP and fluctuations are observed from ∼2115 to 1555 cal yr BP. The results suggest two major climatic phases corresponding with the 4.2 ka and Roman Warm Period (RWP). A regional comparison of mid-late Holocene climate records reveals a broad synchronicity, but with considerable spatial variation. The timing and duration of climate events varied across regions.

Endogenously Produced Jasmonates Affect Leaf Growth and Improve Osmotic Stress Tolerance in Emmer Wheat.

In light of recent climate change, with its rising temperatures and precipitation changes, we are facing the need to increase the valuable crop's tolerance against unfavorable environmental conditions. Emmer wheat is a cereal crop with high nutritional value. We investigated the possibility of improving the stress tolerance of emmer wheat by activating the synthesis of the stress hormone jasmonate by overexpressing two genes of the jasmonate biosynthetic pathway from Arabidopsis thaliana, ALLENE OXIDE SYNTHASE (AtAOS) and OXOPHYTODIENOATE REDUCTASE 3 (AtOPR3). Analyses of jasmonates in intact and mechanically wounded leaves of non-transgenic and transgenic plants showed that the overexpression of each of the two genes resulted in increased wounding-induced levels of jasmonic acid and jasmonate-isoleucine. Against all expectations, the overexpression of AtAOS, encoding a chloroplast-localized enzyme, does not lead to an increased level of the chloroplast-formed 12-oxo-phytodienoic acid (OPDA), suggesting an effective conversion of OPDA to downstream products in wounded emmer wheat leaves. Transgenic plants overexpressing AtAOS or AtOPR3 with increased jasmonate levels show a similar phenotype, manifested by shortening of the first and second leaves and elongation of the fourth leaf, as well as increased tolerance to osmotic stress induced by the presence of the polyethylene glycol (PEG) 6000.

Interactions between climate change, urban infrastructure and mobility are driving dengue emergence in Vietnam

Dengue is expanding globally, but how dengue emergence is shaped locally by interactions between climatic and socio-environmental factors is not well understood. Here, we investigate the drivers of dengue incidence and emergence in Vietnam, through analysing 23 years of district-level case data spanning a period of significant socioeconomic change (1998-2020). We show that urban infrastructure factors (sanitation, water supply, long-term urban growth) predict local spatial patterns of dengue incidence, while human mobility is a more influential driver in subtropical northern regions than the endemic south. Temperature is the dominant factor shaping dengue’s distribution and dynamics, and using long-term reanalysis temperature data we show that warming since 1950 has expanded transmission risk throughout Vietnam, and most strongly in current dengue emergence hotspots (e.g., southern central regions, Ha Noi). In contrast, effects of hydrometeorology are complex, multi-scalar and dependent on local context: risk increases under either short-term precipitation excess or long-term drought, but improvements in water supply mitigate drought-associated risks except under extreme conditions. Our findings challenge the assumption that dengue is an urban disease, instead suggesting that incidence peaks in transitional landscapes with intermediate infrastructure provision, and provide evidence that interactions between recent climate change and mobility are contributing to dengue’s expansion throughout Vietnam.

Univariate and bivariate spatiotemporal characteristics of heat waves and relative influence of large-scale climate oscillations over India

Heat waves (HWs) have grown in frequency, duration, and intensity in last few decades globally and even the latest climate projections (CMIP6) reveal these to get worsen under enhanced global warming. HWs have adverse impacts over biophysical and human systems, therefore, to analyse the impacts of HWs accurately, it is required to understand the regional trend and variability associated with HWs. We carried out a bivariate copula-based joint exceedance probabilistic analysis of HW characteristics to better assess the vulnerability of Indian regions. The regions with comparatively higher HW frequency, higher intensity, longer duration, and lower joint return period of HW frequency and intensity were selected as vulnerable to HWs. Rajasthan, Madhya Pradesh, Uttar Pradesh, Punjab, Bihar, Chhattisgarh, Gujrat, Karnataka, Maharashtra, Telangana, Andhra Pradesh, and Odisha states of India have been found vulnerable and are projected to get even more vulnerable in the future as per the recent climate projections. To unveil the spatiotemporal variability in HW characteristics, we investigated the relative influence of crucial large-scale climate oscillations (LSCOs) i.e., ENSO, IOD, and AMO on HW by introducing these atmospheric variables as covariates in nonstationary extreme value theory (EVT)-based models. The statistical analysis from generalized extreme value distribution of temperature extreme with LSCOs reveals that ENSO and IOD simultaneously have been influencing the extreme in 21.2%, 25.9% and 23.1% of total region taken into consideration in April, May and June month respectively.

Climate-related variation in leaf size and phenology of Betula ermanii in multiple common gardens

ABSTRACT Leaf phenology and properties are the vital traits of productivity and fitness of individual trees. Understanding the climatic conditions associated with the trait variation is essential for evaluation of the tree species’ capacity to face and adapt to environmental change. This study focused on the habits of the tree species in the alpine forests where they are experiencing some of the highest rates of warming under recent climate change. Thus, we examined the climate-related variation in leaf area, specific leaf area (SLA) and the timing of bud break in common gardens of Betula ermanii across a wide latitudinal range, as well as their height that was strongly correlated with leaf traits. Based on analysis of variance, all recorded traits were found to be genetically controlled, and leaf area was most strongly affected by genetic factors. Traits of saplings from higher latitudinal populations included taller height, larger leaf area, larger SLA and earlier bud break. Leaf area of B. ermanii saplings was strongly correlated with the height of the saplings, as taller saplings exhibited larger leaves. Saplings derived from regions with fewer precipitation in summer showed taller height and larger leaves. In contrast, we could not observe significant associations between SLA and timing of bud break, and any climatic variable for two experimental years. Increasing earliness of bud break of B. ermanii with increases in latitude was likely to associate with the gradients of photoperiod. Climate gradients between populations seemed to contribute to the geographic variation in the height, leaf and phenological traits of B. ermanii.

Climate change altered the dynamics of stand dominant height in forests during the past century – Analysis of 20 European tree species

Analyzing how climate change has affected forest growth is crucial for predicting future dynamics and adapting forest management to future climate change. In this paper, we investigate how climate change has modified stand dominant height dynamics and site index of 20 European tree species. We used an innovative method based on an annual height increment equation to model stand dominant height as a function of climate back to 1872 and of other stand environmental conditions. We used these models to simulate stand dominant height dynamics and site index under two different climates (prior to climate change and actual recent climate) to analyze the impact of climate change over the past century. To build our models, we combined the recently published FYRE long-term climate database, which provides daily data since 1871, with data from more than 17,000 forest stands of the French National Forest Inventory network. Higher temperature, precipitation and climatic water balance generally favor stand dominant height dynamics when the variables are considered separately. However, the positive effects often saturate at the higher end of the variable distribution. Over the past century, the effect of climate change on the site index has varied widely among species, ranging from a decrease of less than 3% to an increase of more than 5%. The effect of climate change has also varied within species, with more positive effects on initially temperature-limited stands for some species. For the species and environmental conditions considered, our results highlight a positive response of site index to past climate change for most species, albeit with between- and within-species differences. Our results also suggest that this positive response could become negative under continued climate change. These conclusions, as well as the quantitative relationships we provide between climate and stand dominant height dynamics or site index, will help design management strategies to adapt forests to climate change.

Holocene climate changes and paleoecology on the Tibetan Plateau: recent advances

Holocene climate changes and paleoecology on the Tibetan Plateau: recent advances

Stochastic Precipitation Model Using Large Ensemble Data

A precipitation dataset is created to estimate a reproduction period of several thousand years for stochastic flood risk assessment in the non-life insurance sector. A stochastic precipitation model for natural hazard risk assessment developed in a previous study was applied to a large ensemble data. The model was used to obtain the precipitation ensembles for the recent and future climate by +2 K and +4 K increases in mean temperature, respectively. We successfully created 10,000 years of precipitation data, which makes it possible to obtain precipitation data over a 1,000-year return period.