Future Warming Scenarios Research Articles

Invasive potential of golden and zebra mussels in present and future climatic scenarios in the new world

Biological invasions and climate change are important drivers of biodiversity loss. In freshwater ecosystems, golden and zebra mussels are two highly aggressive invasive species that have caused ecological and economic damages in South and North America, respectively. Here, we used ecological niche models (ENMs) to investigate the invasive potential of golden and zebra mussels in present and future scenarios of global warming in the New World. We found two main patterns in the distribution of suitable areas for golden and zebra mussels. First, the distribution of potentially suitable areas, both in present and future scenarios, is different between mussel species: zebra mussel has areas that are more suitable in temperate regions, while suitable areas for golden mussel are concentrated in tropical and subtropical regions. Second, suitable habitats for golden mussel will increase more in future global warming scenarios compared to suitable habitats for zebra mussel. Indeed, there are experimental indications that zebra mussel has a lower tolerance to high temperatures compared to golden mussel, which is in agreement with our findings. We recommend that the future monitoring of both golden and zebra mussels in the New World should consider areas of highest thermic suitability for current and future scenarios.

Thermal tolerance and the importance of microhabitats for Andean frogs in the context of land use and climate change.

Global warming is having impacts across the Tree of Life. Understanding species' physiological sensitivity to temperature change and how they relate to local temperature variation in their habitats is crucial to determining vulnerability to global warming. We ask how species' vulnerability varies across habitats and elevations, and how climatically buffered microhabitats can contribute to reduce their vulnerability. We measured thermal sensitivity (critical thermal maximum-CTmax ) of 14 species of Pristimantis frogs inhabiting young and old secondary, and primary forests in the Colombian Andes. Exposure to temperature stress was measured by recording temperature in the understorey and across five microhabitats. We determined frogs' current vulnerability across habitats, elevations and microhabitats accounting for phylogeny and then ask how vulnerability varies under four warming scenarios: +1.5, +2, +3 and +5°C. We found that CTmax was constant across species regardless of habitat and elevation. However, species in young secondary forests are expected to become more vulnerable because of increased exposure to higher temperatures. Microhabitat variation could enable species to persist within their thermal temperature range as long as regional temperatures do not surpass +2°C. The effectiveness of microhabitat buffering decreases with a 2-3°C increase, and is almost null under a 5°C temperature increase. Microhabitats will provide thermal protection to Andean frog communities from climate change by enabling tracking of suitable climates through short distance movement. Conservation strategies, such as managing landscapes by preserving primary forests and allowing regrowth and reconnection of secondary forest would offer thermally buffered microhabitats and aid in the survival of this group.

Future projections of winter cold surge paths over East Asia from CMIP6 models

AbstractPrevious studies using observed data suggested a decreasing trend in the frequency of cold surge (CS) over East Asia (EA) under global warming. However, the future change of CSs in different paths is relatively understudied. In this study, after evaluating the classification of CSs paths and the trend of CSs in different paths in historical simulation, the changes of CS paths in EA in future warming scenario have been investigated using the latest 21 models from the phase six of the Coupled Model Intercomparison Project (CMIP6) under the shared socioeconomic pathways (SSP245) scenario. First of all, the observed paths of winter CS in EA from 1979 to 2013 are tracked by the Flexible Particle (FLEXPART) model using ERA‐Interim daily reanalysis datasets, and the CS paths are divided into the northwestern path, northern path, and western path by hierarchical clustering algorithm. Random forest algorithm is introduced to match the future CSs according to the observed classification results. The projected results indicate that the frequency of total CSs will decrease significantly in the 21st century with a trend of −0.47 times/10a. Compared with the late 20th century, the total CSs, the CSs in the northwestern path and the western path decrease by 49, 61, and 60%, respectively, in the late 21st century, while the CSs in northern path do not show a significant trend. The substantial decrease of the northwestern path CSs and the western path CSs make the proportion of northern path CSs in total CSs rise from 19.5% in the late 20th century to 37.3% in the late 21st century. It means the strong CSs are still frequent in the future, probably due to the stability of the northern path CSs.

Implications of Projected Hydroclimatic Change for Tularemia Outbreaks in High-Risk Areas across Sweden.

Hydroclimatic change may affect the range of some infectious diseases, including tularemia. Previous studies have investigated associations between tularemia incidence and climate variables, with some also establishing quantitative statistical disease models based on historical data, but studies considering future climate projections are scarce. This study has used and combined hydro-climatic projection outputs from multiple global climate models (GCMs) in phase six of the Coupled Model Intercomparison Project (CMIP6), and site-specific, parameterized statistical tularemia models, which all imply some type of power-law scaling with preceding-year tularemia cases, to assess possible future trends in disease outbreaks for six counties across Sweden, known to include tularemia high-risk areas. Three radiative forcing (emissions) scenarios are considered for climate change projection until year 2100, incuding low (2.6 Wm−2), medium (4.5 Wm−2), and high (8.5 Wm−2) forcing. The results show highly divergent changes in future disease outbreaks among Swedish counties, depending primarily on site-specific type of the best-fit disease power-law scaling characteristics of (mostly positive, in one case negative) sub- or super-linearity. Results also show that scenarios of steeper future climate warming do not necessarily lead to steeper increase of future disease outbreaks. Along a latitudinal gradient, the likely most realistic medium climate forcing scenario indicates future disease decreases (intermittent or overall) for the relatively southern Swedish counties Örebro and Gävleborg (Ockelbo), respectively, and disease increases of considerable or high degree for the intermediate (Dalarna, Gävleborg (Ljusdal)) and more northern (Jämtland, Norrbotten; along with the more southern Värmland exception) counties, respectively.

The influence of climate and habitat on stable isotope signatures and the isotopic niche of nestling White-headed Woodpeckers (Dryobates albolarvatus).

The majority of landbird species feed their nestlings arthropods and variation in arthropod populations can impact reproductive outcomes in these species. Arthropod populations in turn are influenced by climate because temperature affects survival and reproduction, and larval development. Thus, climate factors have the potential to influence many bird species during their reproductive phases. In this study, we assessed climate factors that impact the diet of nestling White‐headed Woodpecker (Dryobates albolarvatus), an at‐risk keystone species in much of its range in western North America. To do this, we measured stable isotope signatures (δ13C and δ15N) in 152 nestlings across six years and linked variation in isotopic values to winter (December–February) and spring (June) precipitation and temperature using mixed effects models. We also explored habitat factors that may impact δ13C and δ15N and the relationship between δ15N and nest productivity. Last, we estimated isotopic niche width for nestlings in different watersheds and years using Bayesian standard ellipses, which allowed us to compare dietary niche width and overlap. We found that colder winter temperatures were associated with an increase in δ15N and δ15N levels had a weak positive relationship with nest productivity. We also found that sites with a more diverse tree community were associated with a broader isotopic niche width in nestlings. Our findings suggest that nestling diet is affected by climate, and under future warming climate scenarios, White‐headed Woodpecker nestling diet may shift in favor of lower trophic level prey (prey with lower δ15N levels). The impact of such changes on woodpecker populations merits further study.

Vegetation response to climate zone dynamics and its impacts on surface soil water content and albedo in China

Extensive research has focused on the response of vegetation to climate change, including potential mechanisms and resulting impacts. Although many studies have explored the relationship between vegetation and climate change in China, research on spatiotemporal distribution changes of climate regimes using natural vegetation as an indicator is still lacking. Further, limited information is available on the response of vegetation to shifts in China's regional climatic zones. In this study, we applied Mann–Kendall, and correlation analysis to examine the variabilities in temperature, precipitation, surface soil water, normalised difference vegetation index (NDVI), and albedo in China from 1982 to 2012. Our results indicate significant shifts in the distribution of Köppen–Geiger climate classes in China from 12.08% to 18.98% between 1983 and 2012 at a significance level of 0.05 (MK). The percentage areas in the arid and continental zones expanded at a rate of 0.004%/y and 0.12%/y, respectively, while the percentage area in the temperate and alpine zones decreased by −0.05%/y and − 0.07%/y. Sensitivity fitting results between simulated and observed changes identified temperature to be a dominant control on the dynamics of temperate (r2 = 0.98) and alpine (r2 = 0.968) zones, while precipitation was the dominant control on the changes of arid (r2 = 0.856) and continental (r2 = 0.815) zones. The response of the NDVI to albedo infers a more pronounced radiative response in temperate (r = −0.82, p < .01) and alpine (r = −0.476, p < .05) compared to arid and continental zones. Furthermore, we identified more pronounced monthly increasing trends in NDVI and soil water, corresponding to weak changes in albedo during vegetation growing periods. Our results suggest that climate zone shifting has considerable impacts on the vegetation in China and will have larger ecological impacts through radiative or non-radiative feedback mechanisms in future warming scenarios.

Assessment of uncertainties in projecting future changes to extreme storm surge height depending on future SST and greenhouse gas concentration scenarios

We assess uncertainties in projecting future changes in extreme storm surge height (SSH) based on typhoon data extracted from ensemble experiment results with four sea surface temperature (SST) conditions and three global warming scenarios using a single atmospheric global climate model. In particular, this study focus on typhoons passing around the Korean Peninsula (KP) defined as the region of 32 to 40° N and 122 to 132° E. It is predicted the number of the typhoons affecting the KP will decrease by 4~73% while their strength will increase by 0.8~1.4% under the given future conditions. The locations of genesis and lysis of the typhoons are expected to be shifted towards the northwest and northeast for all ensemble experiment conditions, respectively. However, the extent of their change varies depending on the future SST and global warming conditions. Storm surge simulations were carried out by using predicted typhoon data as an external force. It is found that future SST patterns and climate warming scenarios affect future typhoon characteristics, which influences values of extreme SSH and locations of the vulnerable area to storm surge under the future climate conditions. In particular, the values of extreme SSH and the locations of the vulnerable area to storm surge appear to be strongly influenced by both pathway and frequency of intense typhoons.

Contrasting impacts of the 8.2‐ and 4.2‐ka abrupt climatic events on the regional vegetation of the Hulun Lake region in north‐eastern China

ABSTRACTStudies of the vegetation response to abrupt climatic events may provide valuable insights into assessing the impacts of such events under future global warming scenarios. Here we present a detailed record of regional vegetation change based on high‐resolution pollen records for the intervals 9000–7000 and 5000–3000 cal a bp from the Hulun Lake region of north‐eastern China. Our aims were to determine the regional expression of the 8.2‐ and 4.2‐ka events in north‐eastern China, especially their effects on vegetation composition. The results show that the response of the vegetation of the Hulun Lake region to the climatic cooling of the 8.2‐ka event was relatively minor; however, the 4.2‐ka event, which resulted in climatic aridification, resulted in pronounced vegetation degradation. We suggest that the specific characteristics of the 8.2‐ and 4.2‐ka events, together with their duration and the regional climatic background on an orbital time scale, were the main factors responsible for the contrasting vegetation responses. The strengthening and northward shift of the Intertropical Convergence Zone (ITCZ) tended to offset the cooling effect of the 8.2‐ka event on regional vegetation in the mid–high latitudes of East Asia; in contrast, the decrease in summer insolation in the Northern Hemisphere and the southward shift of the ITCZ may have intensified the drought effect of the 4.2‐ka event in East Asia and the associated vegetation degradation. Under future global warming scenarios, both extreme cooling events and extreme drought events may cause a deterioration of the ecological environment; however, the resulting regional vegetation responses may be substantially different.

Spring phenophases of larch are more sensitive to spring warming than to year-round warming: Results of a seasonally asymmetric warming experiment

Plant phenology is a highly sensitive indicator of climate change. The advancement in time of spring phenology due to climate warming is well documented. However, although the progressive warming process is asymmetrical across seasons in temperate and boreal regions, the consistency of spring phenological response to non-uniform seasonal warming has not been well studied. Furthermore, the different responses of budburst and leaf unfolding to seasonally uneven warming have not been fully explored. We investigated the responses of budburst and leaf unfolding in two-year-old larch (Larix principis-rupprechtii) seedlings to seasonally asymmetric warming treatments (with passive warming applied in open-top chambers) in northern China. We found that spring warming significantly advanced budburst and leaf unfolding by 7 and 2 days, respectively; year-round warming advanced budburst by 4 days but had no impact on the timing of leaf unfolding. Summer and winter warming had no effects on the timing and duration of spring phenophases. Notably, spring leaf unfolding was significantly delayed, by 2 days, following an autumnal warming, i.e., there was a carry-over effect (a 1-day delay in leaf senescence delayed leaf unfolding by 0.3 day in the next spring). The temperature sensitivities of budburst and leaf unfolding in the spring warming treatment (9.56 days/°C and 2.66 days/°C, respectively) were significantly greater than those in the year-round warming treatment (6.43 days/°C and 0.66 days/°C, respectively). We also found a trade-off relationship between the durations of budburst and leaf unfolding in the spring and year-round warming treatments. Our demonstration of (i) differences in the magnitude of responses between budburst and leaf unfolding, and (ii) the carry-over effect under non-uniform seasonal warming, should be incorporated into modeling simulations of spring phenological responses to future warming scenarios. Overall, our findings would have some critical implications for resistance and performance (e.g., frost damage risk and carbon uptake) in the seedling stage of plantation establishment under ongoing climate warming scenarios.

Terrestrial Salamanders Maintain Habitat Suitability under Climate Change despite Trade-Offs between Water Loss and Gas Exchange.

Physiological acclimation has the potential to improve survival during climate change by reducing sensitivity to warming. However, acclimation can produce trade-offs due to links between related physiological traits. Water loss and gas exchange are intrinsically linked by the need for respiratory surfaces to remain moist. As climates warm and dry, organisms may attempt to lower desiccation risk by limiting water loss but at a cost of inhibiting their ability to breathe. Here we used laboratory experiments to evaluate the trade-off between water loss and gas exchange in a fully terrestrial, lungless salamander (Plethodon metcalfi). We measured acclimation of resistance to water loss and metabolic rates in response to long-term exposure to temperature and humidity treatments. We then integrated the trade-off into a simulation-based species distribution model to determine the consequences of ignoring physiological trade-offs on energy balance and aerobic scope under climate change. In the laboratory, we found a close association between acclimation of resistance to water loss and metabolic rates indicative of a trade-off. After incorporating the trade-off into our simulations, we found that energy balance and aerobic scope were reduced by 49.7% and 34.3%, respectively, under contemporary climates across their geographic range. Under future warming scenarios, incorporating the trade-off lowered the number of sites predicted to experience local extirpation by 52.2% relative to simulations without the trade-off; however, the number of sites capable of supporting the energetic requirements for reproduction declined from 44.6% to 32.6% across the species' geographic range. These experiments and simulations suggest that salamanders can maintain positive energy balance across their geographic range under climate change despite the costs associated with trade-offs between water loss and gas exchange.

The atmospheric moisture budget in the Mediterranean: Mechanisms for seasonal changes in the Last Glacial Maximum and future warming scenario

We have investigated the sensitivity of the Mediterranean atmospheric moisture budget (P-E) to large global mean temperature changes and the mechanisms for its seasonal changes. Model simulations of the Last Glacial Maximum (LGM) and Representative Concentration Pathway rcp8.5 scenario have been compared to pre-Industrial (PI) conditions. We have decomposed (P-E) in thermodynamic, dynamic, transient eddy and surface term. The decomposition revealed that mechanisms for (P-E) changes in the Mediterranean do not follow a simple scaling with temperature from the cold LGM to the warm rcp8.5 and they cannot be described by the thermodynamic contribution associated with the “wet-get-wetter, dry-get-drier” paradigm. Winter changes are caused by the anomalous mean atmospheric circulation. In summer, the thermodynamics provides the largest contribution, but its effect is counteracted by other mechanisms. The Mediterranean response to climate change differs from the averaged behavior of other regions in the same latitudinal belt. The complex spatial interplay of the atmospheric moisture budget contributions results in reduced precipitation in the rcp8.5 and reduced evaporation in the LGM relative to PI. This analysis shows that past (LGM) and future (rcp8.5) atmospheric moisture budget changes have very different basic mechanisms, which cannot be simply linked to changes of global mean temperature.

Coldest Canadian Arctic communities face greatest reductions in shorefast sea ice

Shorefast sea ice comprises only about 12% of global sea-ice cover, yet it has outsized importance for Arctic societies and ecosystems. Relatively little is known, however, about the dominant drivers of its breakup or how it will respond to climate warming. Here, we use 19 years of near-daily satellite imagery to document the timing of shorefast ice breakup in 28 communities in northern Canada and western Greenland that rely on shorefast ice for transportation and traditional subsistence activities. Breakup timing is strongly correlated with springtime air temperature, but the sensitivity of the relationship varies substantially among communities. We combine these observations with future warming scenarios to estimate an annual reduction of 5–44 days in the length of the springtime shorefast ice season by 2100. Paradoxically, the coldest communities are projected to experience the largest reductions in springtime ice season duration. Our results emphasize the local nature of climate change and its varied impacts on Arctic communities. Shorefast sea ice, which forms along the Arctic shore in winter and spring, is important for local communities and ecosystems. Satellite and climate model data are used to estimate a decrease in shorefast ice season length of 5–44 days by 2100, with the coldest areas experiencing the largest reductions.

Foraminiferal holobiont thermal tolerance under future warming – roommate problems or successful collaboration?

Abstract. Understanding the response of marine organisms to expected future warming is essential. Large benthic foraminifera (LBF) are symbiont-bearing protists considered to be major carbonate producers and ecosystem engineers. We examined the thermal tolerance of two main types of LBF holobionts characterized by different algal symbionts and shell types (resulting from alternative biomineralization mechanisms): the hyaline diatom-bearing Amphistegina lobifera and the porcellaneous-dinoflagellate-bearing Sorites orbiculus. In order to assess the holobiont thermal tolerance we separately evaluated foraminiferal calcification rates and symbionts' net photosynthesis under present-day and future warming scenarios. Our results show that both holobionts exhibit progressive loss-of-life functions between 32 and 35 ∘C. This sensitivity differs in the magnitude of their response: calcification of A. lobifera was drastically reduced compared with S. orbiculus. Thus, future warming may significantly shift the relative contribution of the two species as carbonate producers. Moreover, A. lobifera exhibited a synchronous response of calcification and net photosynthesis. In contrast, in S. orbiculus the symbionts decreased net photosynthesis prior to calcification. This implies that algal symbionts limit the resilience of the halobiont.

Soil thermal regime alteration under experimental warming in permafrost regions of the central Tibetan Plateau

Soil thermal regime in permafrost regions is sensitive to climate change and may cause vast ecological consequences under future warming scenarios. However, there still lacks a systematic evaluation on the effect of warming on soil thermodynamics in the different ecosystems of permafrost regions. This study investigated the alterations of soil thermodynamics in alpine swamp meadow and alpine steppe under experimental warming by open-top chambers in permafrost regions of the central Tibetan Plateau. The results showed that air temperature increased significantly with an annual mean increase of 1.4 °C under warming. Compared to alpine swamp meadow, soil thermodynamics represented by soil temperature, soil thermal parameters, soil freeze-thaw process and active layer thickness in alpine steppe was more susceptible to warming. Specifically, soil temperature at 5–40 cm depths increased more in alpine steppe than alpine swamp meadow under warming, especially at topsoil (5–20 cm). Moreover, the increase in soil temperature at topsoil was greater during cold season than warm season. Greater alterations of soil thermal parameters were likely because soil moisture content reduced more in alpine steppe. Regarding soil freeze-thaw process, warming significantly postponed the onset of completely frozen stage and reduced the completely frozen days in alpine steppe. Active layer thickness in alpine steppe distinctly increased by 46 cm on average and showed an increasing trend under warming from 2009 to 2011. Overall, vegetation coverage and soil moisture content were responsible for the different responses of soil thermodynamics to experimental warming. The study has important implications for future scenarios as permafrost and grassland degradation may intensify under climate warming.

Warming and temperature variability determine the performance of two invertebrate predators

In a warming ocean, temperature variability imposes intensified peak stress, but offers periods of stress release. While field observations on organismic responses to heatwaves are emerging, experimental evidence is rare and almost lacking for shorter-scale environmental variability. For two major invertebrate predators, we simulated sinusoidal temperature variability (±3 °C) around todays’ warm summer temperatures and around a future warming scenario (+4 °C) over two months, based on high-resolution 15-year temperature data that allowed implementation of realistic seasonal temperature shifts peaking midpoint. Warming decreased sea stars’ (Asterias rubens) energy uptake (Mytilus edulis consumption) and overall growth. Variability around the warming scenario imposed additional stress onto Asterias leading to an earlier collapse in feeding under sinusoidal fluctuations. High-peak temperatures prevented feeding, which was not compensated during phases of stress release (low-temperature peaks). In contrast, increased temperatures increased feeding on Mytilus but not growth rates of the recent invader Hemigrapsus takanoi, irrespective of the scale at which temperature variability was imposed. This study highlights species-specific impacts of warming and identifies temperature variability at the scale of days to weeks/months as important driver of thermal responses. When species’ thermal limits are exceeded, temperature variability represents an additional source of stress as seen from future warming scenarios.

The combination of palm and rapeseed oils emerges as a good dietary alternative for optimal growth and balanced lipid accumulation in juvenile gilthead sea bream reared at an elevated temperature

The aquaculture sector needs to develop new tools to optimally increase production for feeding, while facing future environmental changing conditions. One of the major improvements in this industry has been reducing the usage of fishmeal and fish oil (FO) in diet formulations to promote a more sustainable production. In this line and considering global warming, in the present study, juvenile gilthead sea bream were fed a diet with a 60% of FO substitution by vegetable oils (VO) containing mainly palm oil (P) (80% of the VO content) and maintained at 21 or 28 °C. Furthermore, in the condition of elevated temperature, fish were fed with two other diets with the same level of FO substitution and containing either 80% of the VO content of rapeseed oil (R) or an equilibrated combination of both VO (named PR). High temperature induced a significant increase in growth, but a reduction in the hepatosomatic and viscerosomatic indexes, and circulating triglycerides. Otherwise, significant differences were not found among the fish fed the three distinct diets at 28 °C for any of the somatic or plasma parameters analyzed. In the adipose tissue, the higher number of adipocytes of smaller size in fish maintained at 28 °C compared to fish at 21 °C, suggested an activation of adipogenesis despite the gene expression of peroxisome proliferator-activated receptor gamma (pparg) was significantly decreased. Furthermore, lipid droplets of smaller area and downregulation of the fat translocase cd36 and the fatty acid binding protein fabp1 were found in the liver of fish reared at 28 °C compared to those at 21 °C. Concerning differences among dietary groups, fish fed R diet showed in the liver a more extensive surface area occupied by lipid droplets of bigger size, while contrarily, fish fed PR diet had the smallest area filled with smaller lipid droplets. In adipose tissue, PR diet-fed fish had also adipocytes within the smaller size range. These histological data, together with the significant upregulation of several transcription factors (i.e. ppars) and genes related to lipid transport in the two tissues, indicated that the PR diet could be the most equilibrated for gilthead sea bream, to grow at a high rearing temperature while avoiding excessive fat accumulation. Thus, this study highlights the need of fine-tuning the substitution of FO by VO in the elaboration of feeds for this species to assure proper growth and physiological status in a future global warming scenario.

Rainfall pattern over the North-West Himalayan region: historical time period vs. future warming scenarios

Events like melting glaciers, rising sea level, and changing weather patterns are being observed across the globe due to widely reported global warming. The monsoon season rainfall in the North-Western Himalayan region (NWH) becomes more uncertain as there is considerable variation between the duration of the monsoon season and the amount of rainfall during the season. The NWH region receives substantial amount of rainfall and witness various disasters during the monsoon season. In this context, the present study deals with the analysis of the rainfall patterns under various future warming scenarios (2076–2100), namely representative concentration pathway scenario 4.5 (RCP 4.5) and RCP 8.5 (RCP 8.5) with respect to the reference historical time period (1976–2000) during the principal monsoon season (i.e. 1st June to 30th September) of two Indian states (Uttarakhand and Himachal Pradesh) of the NWH region. To serve this purpose, six attributes are defined as follows; start date of the rainy season (SRS), date of the 50% of the seasonal total rainfall (HRS), end date of the rainy season (ERS), length of the rainy season (LRS), 1 day maximum intensity (MRS) and the day corresponding to the maximum rainfall intensity (MDRS). These attributes are estimated for both historical time period and various future warming scenarios based on the archives of five coupled climate models which participated in the Climate Model Inter-comparison Project Phase 5 (CMIP5). Considering huge inter-model variations amongst the CMIP5 models, results are presented here based on the multi-model mean (MME). Characteristics of various attributes of rainfall during the historical time period are compared with that of the two future warming scenarios viz.; RCP 4.5 and RCP 8.5 by means of statistical techniques. There is a possibility of early SRS, delayed ERS and extended LRS along with intense MRS under different future warming scenarios over Himachal Pradesh (HP) as compared with the historical time period; however, results are significant only for 1 day maximum rainfall under RCP 8.5. Similarly, over the Uttarakhand (UK) region, changes in the rainfall pattern are noted under two future warming scenarios viz.; RCP 4.5 and RCP 8.5 as compared with the historical time period; nonetheless, significant changes are noted in MRS and MDRS only under RCP 8.5. It is anticipated that both of the NWH states of HP and UK would experience enhanced MRS under the warmest future warming scenario (i.e. RCP 8.5). Based on the present analysis, intense rainfall events are expected which could act as an initiator for various meteorological hazards over the NWH region in future.

Substrate rugosity and temperature matters: patterns of benthic diversity at tropical intertidal reefs in the SW Atlantic.

Modeling and forecasting ocean ecosystems in a changing world will require advances in observational efforts to monitor marine biodiversity. One of the observational challenges in coastal reef ecosystems is to quantify benthic and climate interactions which are key to community dynamics across habitats. Habitat complexity (i.e., substrate rugosity) on intertidal reefs can be an important variable explaining benthic diversity and taxa composition, but the association between substrate and seasonal variability is poorly understood on lateritic reefs in the South Atlantic. We asked if benthic assemblages on intertidal reefs with distinct substrate rugosity would follow similar seasonal patterns of succession following meteo-oceanographic variability in a tropical coastal area of Brazil. We combined an innovative 3D imaging for measuring substrate rugosity with satellite monitoring to monitor spatio-temporal patterns of benthic assemblages. The dataset included monthly in situ surveys of substrate cover and taxon diversity and richness, temporal variability in meteo-oceanographic conditions, and reef structural complexity from four sites on the Eastern Marine Ecoregion of Brazil. Additionally, correlation coefficients between temperature and both benthic diversity and community composition from one year of monitoring were used to project biodiversity trends under future warming scenarios. Our results revealed that benthic diversity and composition on intertidal reefs are strongly regulated by surface rugosity and sea surface temperatures, which control the dominance of macroalgae or corals. Intertidal reef biodiversity was positively correlated with reef rugosity which supports previous assertions of higher regional intertidal diversity on lateritic reefs that offer increased substrate complexity. Predicted warming temperatures in the Eastern Marine Ecoregion of Brazil will likely lead to a dominance of macroalgae taxa over the lateritic reefs and lower overall benthic diversity. Our findings indicate that rugosity is not only a useful tool for biodiversity mapping in reef intertidal ecosystems but also that spatial differences in rugosity would lead to very distinct biogeographic and temporal patterns. This study offers a unique baseline of benthic biodiversity on coastal marine habitats that is complementary to worldwide efforts to improve monitoring and management of coastal reefs.

Response of the Japanese flying squid (Todarodes pacificus) in the Japan Sea to future climate warming scenarios

The Japanese flying squid (Todarodes pacificus) is an important fishery resource in East Asia, including Japan, China, and Korea. Recent studies have suggested that it exhibits significant interannual variation with a close relationship with environmental variables, among which water temperature has an apparent influence on its spawning, hatching, and growth. Therefore, we need to understand how the Japanese flying squid in the Japan Sea (JS) will be affected by global warming. Based on particle tracking methods, we simulated migration and individual growth of Japanese flying squid from spawning to juveniles (182 days) in six cases: one for high-level catch years (1960–1966), one for low-level catch years (2008–2014), and four for the future, including two for 50 years (2056–2062) and two for 100 years from now (2104–2110) under the warming scenario of RCP2.6 and RCP8.5, respectively. The simulations showed that the number of squid increased with warming. The main reason for the increase was the warming of the JS, which increased the survival rate of autumn- and winter-spawning cohorts. In addition, the model also demonstrated the potential effects of warming on the physiological process of the early life stage of the Japanese flying squid.

Hydroclimate variability from western Iberia (Portugal) during the Holocene: Insights from a composite stalagmite isotope record

Iberia is predicted under future warming scenarios to be increasingly impacted by drought. While it is known that this region has experienced multiple intervals of enhanced aridity over the Holocene, additional hydroclimate-sensitive records from Iberia are necessary to place current and future drying into a broader perspective. Toward that end, we present a multi-proxy composite record from six well-dated and overlapping speleothems from Buraca Gloriosa (BG) cave, located in western Portugal. The coherence between the six stalagmites in this composite stalagmite record illustrates that climate (not in-cave processes) impacts speleothem isotopic values. This record provides the first high-resolution, precisely dated, terrestrial record of Holocene hydroclimate from west-central Iberia. The BG record reveals that aridity in western Portugal increased secularly from 9.0 ka BP to present, as evidenced by rising values of both carbon (δ13C) and oxygen (δ18O) stable isotope values. This trend tracks the decrease in Northern Hemisphere summer insolation and parallels Iberian margin sea surface temperatures (SST). The increased aridity over the Holocene is consistent with changes in Hadley Circulation and a southward migration of the Intertropical Convergence Zone (ITCZ). Centennial-scale shifts in hydroclimate are coincident with changes in total solar irradiance (TSI) after 4 ka BP. Several major drying events are evident, the most prominent of which was centered around 4.2 ka BP, a feature also noted in other Iberian climate records and coinciding with well-documented regional cultural shifts. Substantially, wetter conditions occurred from 0.8 ka BP to 0.15 ka BP, including much of the ‘Little Ice Age’. This was followed by increasing aridity toward present day. This composite stalagmite proxy record complements oceanic records from coastal Iberia, lacustrine records from inland Iberia, and speleothem records from both northern and southern Spain and depicts the spatial and temporal variability in hydroclimate in Iberia.