Future Climate Variability Research Articles

The history of vegetation and landscapes of the lake Ilchir basin for understanding the modern vegetation structure in the Okinsky plateau

The method of detailed sampling of sediments from Lake Ilchir allowed obtaining a high-resolution record of changes in the natural environment, which meets the world modern standards of temporal resolution in the studies of the Holocene environment. The data on the palynological analysis of bottom sediments from Lake Ilchir (51°58’26.0” N and 100°59’29.0” E) enable us to reconstruct the composition of vegetation and the structure of landscapes in the lake basin as well as to understand the process of its change in Middle-Late Holocene. The lake is located in the Republic of Buryatia and is the source of the Irkut River, which flows into the Angara River. The results obtained are unique for the regional Holocene environment, since they allow us to clarify the nature of changes in regional vegetation with an average time interval of 125 years. A reliable age model provides for intra-and interregional correlations of environmental changes that helps to understand the possible causes of changes in regional vegetation. Palynological records from inland regions are important for reconstructing the processes of past changes in landscapes, assessing the sensitivity of ecosystems in these regions to future climatic variations that affect the composition of vegetation and its change in time.

Future climate variability will challenge rangeland beef cattle production in the Great Plains

Climate projections indicate the Great Plains will experience higher mean temperatures and greater interannual precipitation variability in the future.Greater precipitation variability will challenge the economic viability of rangeland beef cattle production by further disrupting forage supply and animal demand.Beef producers are uncertain of future climate impacts, indicating assistance with adaptive strategies is needed.Private-state-national partnerships may help sustain rangelands and economically viable beef cattle production with increasing climate variability.

Quantifying soil-respired CO2 on the Chinese Loess Plateau

Soil respiration is one of the dominant fluxes of CO2 from terrestrial ecosystems to the atmosphere. Accurate quantification of soil respiration is essential for robust projection of future climate variation and for reliable estimation of paleoatmospheric CO2 levels using soil carbonates. Soil-respired CO2, which is the most uncertain factor in estimating atmospheric CO2 concentration, has been calculated from modern observations of surface soils and from proxy indicators of paleosols formed during time periods of known atmospheric CO2. However, these estimations provide a wide range of S(z) values from past to present. To directly compare modern observation with past estimation, here we first monitored soil CO2 profiles in a Holocene profile on the western Chinese Loess Plateau (CLP) for two years, providing direct measurements of soil-respired CO2 at the depth where carbonate nodules likely formed. We then collected carbonate nodules below last interglacial paleosol (S1) from two N-S-aligned transects across the CLP to back-calculate soil-respired CO2. The mean back-calculated S(z) from S1 carbonate nodules vary from 539 ± 87 ppm to 848 ± 170 ppm in the sections on the northwestern and southeastern CLP, respectively. The mean value of directly measured soil-respired CO2 on the western CLP is 572 ± 273 ppm before the onset of summer monsoon, consistent with the back-calculated S(z) in northwestern sections. Our results suggest that spatial S(z) variations are mainly controlled by monsoonal precipitation during the summer season on the CLP. To better constrain the high end of S(z), more monitoring work is needed in higher precipitation areas on the southeastern CLP.

Impacts of land use, population, and climate change on global food security

AbstractIn recent years, global hunger has begun to rise, returning to levels from a decade ago. Climate change is a key driver behind these recent rises and is one of the leading causes of severe food crises. When coupled with population growth and land use change, future climate variability is predicted to have profound impacts on global food security. We examine future global impacts of climate variability, population, and land use change on food security to 2050, using the modeling framework FEEDME (Food Estimation and Export for Diet and Malnutrition Evaluation). The model uses national food balance sheets (FBS) to determine mean per capita calories, hence incorporating an assumption that minimum dietary energy requirements (MDER) remain constant. To account for climate variability, we use two Representative Concentration Pathway (RCP) scenarios from the Intergovernmental Panel on Climate Change (IPCC), alongside three Shared Socio‐economic Pathway (SSP) scenarios incorporating land use and population change within the model. Our results indicate that SSP scenarios have a larger impact on future food insecurity, in particular because of projected changes in population. Countries with a projected decrease in population growth had higher food security, while those with a projected rapid population growth tended to experience the worst impacts on food security. Although climate change scenarios had an effect on future crop yields, population growth appeared to be the dominant driver of change in undernourishment prevalence. Therefore, strategies to mitigate the consequences of projected population growth, including improved maternal health care, increasing equality of access to food at the national level, closing the yield gap, and changes in trade patterns, are essential to ensuring severe future food insecurity is avoided.

Contrasting responses of above- and below-ground herbivore communities along elevation

Above- and below-ground herbivory are key ecosystem processes that can be substantially altered by environmental changes. However, direct comparisons of the coupled variations of above- and below-ground herbivore communities along elevation gradients remain sparse. Here, we studied the variation in assemblages of two dominant groups of herbivores, namely, aboveground orthoptera and belowground nematodes, in grasslands along six elevation gradients in the Swiss Alps. By examining variations of community properties of herbivores and their food plants along montane clines, we sought to determine whether the structure and functional properties of these taxonomic groups change with elevation. We found that orthoptera decreased in both species richness and abundance with elevation. In contrast with aboveground herbivores, the taxonomic richness and the total abundance of nematode did not covary with elevation. We further found a stronger shift in above- than below-ground functional properties along elevation, where the mandibular strength of orthoptera matched a shift in leaf toughness. Nematodes showed a weaker pattern of declined sedentary behavior and increased mobility with elevation. In contrast to the direct exposal of aboveground organisms to the surface climate, conditions may be buffered belowground, which together with the influence of edaphic factors on the biodiversity of soil biota, may explain the differences between elevational patterns of above- and below-ground communities. Our study emphasizes the necessity to consider both the above- and below-ground compartments to understand the impact of current and future climatic variation on ecosystems, from a functional perspective of species interactions.

Geochemical insights into groundwater movement in alpine karst, Bear River Range, Utah, USA

Alpine karst aquifers control the availability and longevity of some water resources, but are not well understood. A conceptual model of the alpine karst aquifer system in the Bear River Range of northern Utah (USA) has been developed by geochemical analysis (major ions, δ18O, δ2H and δ13C values) of seasonal water samples from seven perennial springs, and residence-time assessment (3H and CFCs) of two low- and two high-discharge springs. All spring data can be explained by reaction paths dominated by the dissolution of calcian dolomite. The δ13C values align well with reaction paths for open-system dissolution. Saturation indices and low Ca:Mg molar ratios indicate that incongruent dissolution exerts a strong control on water–rock interactions, complicating interpretation of natural solute tracers. Values of δ18O and δ2H in springs follow the Utah meteoric water line. Snow δ18O values correlate with elevation, but not with increasing rainout distance, providing qualitative estimates of recharge elevation that generally align with previous dye-traces to five of the seven springs. Concentrations of 3H and CFCs likely are best described by binary mixing of subannual recharge with 60–65-year-old groundwater, suggesting that the alpine karst aquifer system in the Bear River Range is best represented by a double-porosity model. Subannual recharge documented by dye traces implies that caverns are the primary flowpaths to the springs, but the presence of decadal-age water may indicate that lower permeability flowpaths dominate during baseflow. No evidence was found for a longer-residing flow component, suggesting high sensitivity to future climate variability.

Meridional Ocean Carbon Transport

The ocean's ability to take up and store CO2 is a key factor for understanding past and future climate variability. However, qualitative and quantitative understanding of surface‐to‐interior pathways, and how the ocean circulation affects the CO2 uptake, is limited. Consequently, how changes in ocean circulation may influence carbon uptake and storage and therefore the future climate remains ambiguous. Here we quantify the roles played by ocean circulation and various water masses in the meridional redistribution of carbon. We do so by calculating streamfunctions defined in dissolved inorganic carbon (DIC) and latitude coordinates, using output from a coupled biogeochemical‐physical model. By further separating DIC into components originating from the solubility pump and a residual including the biological pump, air‐sea disequilibrium, and anthropogenic CO2, we are able to distinguish the dominant pathways of how carbon enters particular water masses. With this new tool, we show that the largest meridional carbon transport occurs in a pole‐to‐equator transport in the subtropical gyres in the upper ocean. We are able to show that this pole‐to‐equator DIC transport and the Atlantic meridional overturning circulation (AMOC)‐related DIC transport are mainly driven by the solubility pump. By contrast, the DIC transport associated with deep circulation, including that in Antarctic bottom water and Pacific deep water, is mostly driven by the biological pump. As these two pumps, as well as ocean circulation, are widely expected to be impacted by anthropogenic changes, these findings have implications for the future role of the ocean as a climate‐buffering carbon reservoir.

Coupled application of R and WetSpa models for assessment of climate change impact on streamflow of Werie Catchment, Tigray, Ethiopia

Abstract This research assesses the streamflow response of Werie River to climate change. Baseline (1980–2009) climate data of precipitation, maximum and minimum temperature were analyzed using delta based statistical downscaling approach in R software packages to predict future 90-year (2010–2099) periods under two emission scenarios of Representative Concentration Pathways (RCP) 4.5 and RCP 8.5, indicating medium and extremely high emission scenarios respectively. Generated future climate variables indicate Werie will experience a significant increase in precipitation, and maximum and minimum air temperature for both RCPs. Further, Water and Energy Transfer between Soil, Plants, and Atmosphere (WetSpa) was applied to assess the water balance of Werie River. The WetSpa model reproduced the streamflow well with performance statistics values of R2 = 0.84 and 0.85, Nash–Sutcliffe efficiency = 0.72 and 0.72, and model bias = –0.14 and –0.15 for the calibration data set of 1999–2010 and validation data of 2011–2014, respectively. Finally, by taking the downscaled future climate variables as input, WetSpa future prediction shows that there will be an increase in the Werie catchment mean annual streamflow up to 29.6% for RCP 4.5 and 35.6% for RCP 8.5 compared to the baseline period.

Statically Downscaling using different Representative Concentration Pass ways of Emission Scenario; in the Case Wolikite, South West Ethiopia

Nowadays the sign of climate change and its impact is revealing on different natural and manmade systems, in one or other ways. This study mainly deals to develop future climate change scenario for Wolikite using statistically downscaling of large-scale climate variables. Projection of the future climate variables is done by using Global Circulation Model (GCM) which is considered as the most advanced tool for estimating the future climatic condition. The Statistical Downscaling Model (SDSM) is used to downscale present and future daily precipitation and temperature using observed station data.

The role of internal climate variability in projecting Antarctica\u2019s contribution to future sea-level rise

Retreat of the Antarctic ice sheet (AIS) is likely to be a major contributor to future sea-level rise (SLR). Current projections of SLR due to ice-sheet mass loss remain highly uncertain. Better understanding of how ice sheets respond to future climate forcing and variability is essential for assessing long-term risk of SLR. However, predictability of future climate is limited by uncertainties from emission scenarios, model structural differences, and internal climate variability (ICV) that is inherently generated within the fully coupled climate system. Among those uncertainties, the impact of ICV on the AIS changes has not been explicitly assessed. Here we quantify the effects of ICV on the AIS evolutions by employing climate fields from two large-ensemble experiments using the Community Earth System Model to force a three-dimensional ice-sheet model. We find that ICV of climate fields among ensemble members leads to significantly different AIS responses, and that most of the effect is due to atmospheric variability compared to oceanic. Our results show that ICV can cause about 0.08 m differences of AIS contribution to SLR by 2100 compared to the ensemble-mean AIS contribution of 0.38–0.45 m. Moreover, using ensemble-mean climate forcing fields as the forcing in an ice-sheet model significantly delays retreat of the West AIS for up to 20 years and significantly underestimates the AIS contribution to SLR by 0.07–0.11 m in 2100 and up to 0.34 m in the 2250’s. This study highlights the need to take internal climate variability into account in assessing uncertainty associated with the AIS contribution in sea-level rise projections.

Using a regional climate model to develop index-based drought insurance for sovereign disaster risk transfer

PurposeExamine the usability of rainfall and temperature outputs of a regional climate model (RCM) and meteorological drought indices to develop a macro-level risk transfer product to compensate the government of Central Java, Indonesia, for drought-related disaster payments to rice farmers.Design/methodology/approachBased on 0.5° gridded rainfall and temperature data (1960–2015) and projections of the WRF-RCM (2016–2040), the Standardized Precipitation Index (SPI) and the Standardized Precipitation Evapotranspiration Index (SPEI) are calculated for Central Java over different time spans. The drought indices are correlated to annual and seasonal rice production, based on which a weather index insurance structure is developed.FindingsThe six-month SPI correlates best with the wet season rice production, which generates most output in Central Java. The SPI time series reveals that drought severity increases in future years (2016–2040) and leads to higher payouts from the weather index structure compared to the historical period (1960–2015).Practical implicationsThe developed methodology in using SPI for historical and projected periods allows the development of weather index insurance in other regions which have a clear link between rainfall deficit and agricultural production volatility.Originality/valueMeteorological drought indices are a viable alternative for weather index insurance, which is usually based on rainfall amounts. RCM outputs provide valuable insights into future climate variability and drought risk and prolong the time series, which should result in more robust weather index insurance products.

Recognizing Allogenic Controls on the Stratigraphic Architecture of Ancient Alluvial Fans in the Western US

Alluvial fans are a significant part of the sediment routing system, forming distinctive steep, fan-shaped deposits of coarse-grained detritus where rivers lose flow velocity after exiting confined mountain drainages. Processes on the fan are influenced by both internal (autogenic) feedback cycles like channel avulsion and by external (allogenic) conditions such as climate and tectonics. These conditions in turn influence the stratigraphic architecture (i.e., the pattern of channel stacking and sizes) within the fan. Studying stratigraphic architecture of alluvial fans can, therefore, provide insight into controls on fan deposition. We employ UAV-based photogrammetric models to analyze the stratigraphic architecture of two well-exposed ancient alluvial fans in the western US – the Eocene Richards Mountain Conglomerate and the Cretaceous Echo Canyon Conglomerate. Both fans were deposited under relatively warm, wet climates and compressional tectonic regimes. We use a seven-fold hierarchy of bounding surfaces and associated lithosomes to describe alluvial fan architecture. First- through fourth-order surfaces and lithosomes represent bedform to channel-scale features influenced primarily by autogenic processes on the fan. Controls on fifth-order surfaces/lithosomes have historically been poorly understood, but probably represent fanhead trench migration and lobe construction. Sixth-order surfaces bound individual alluvial fans and seventh-order surfaces correspond to formation boundaries. These are controlled primarily by tectonics. The fifth-order architectural style of the deposits in our two study areas is significantly different and we use this difference to try to isolate a primary control on fifth-order alluvial architecture. Average width:height ratios of fifth-order lithosomes are nearly twice as high for Echo Canyon (112:1) than for Richards Mountain (64:1). This indicates that active channels on the Echo Canyon fan were more mobile than those on the Richards Mountain fan. We attribute this to a more seasonal climate and less vegetation during the deposition of the Echo Canyon Conglomerate. This would have increased lateral migration by destabilizing channels through increased sediment flux and flood events. Our results imply that fifth-order stratigraphic architecture of ancient alluvial fans may provide insight into allogenic processes related to paleoclimate. They also indicate risk of increased geologic hazards on alluvial fans where anthropogenic climate change increases future climate variability.

Towards climate resilient urban energy systems: a review.

Climate change and increased urban population are two major concerns for society. Moving towards more sustainable energy solutions in the urban context by integrating renewable energy technologies supports decarbonizing the energy sector and climate change mitigation. A successful transition also needs adequate consideration of climate change including extreme events to ensure the reliable performance of energy systems in the long run. This review provides an overview of and insight into the progress achieved in the energy sector to adapt to climate change, focusing on the climate resilience of urban energy systems. The state-of-the-art methodology to assess impacts of climate change including extreme events and uncertainties on the design and performance of energy systems is described and discussed. Climate resilience is an emerging concept that is increasingly used to represent the durability and stable performance of energy systems against extreme climate events. However, it has not yet been adequately explored and widely used, as its definition has not been clearly articulated and assessment is mostly based on qualitative aspects. This study reveals that a major limitation in the state-of-the-art is the inadequacy of climate change adaptation approaches in designing and preparing urban energy systems to satisfactorily address plausible extreme climate events. Furthermore, the complexity of the climate and energy models and the mismatch between their temporal and spatial resolutions are the major limitations in linking these models. Therefore, few studies have focused on the design and operation of urban energy infrastructure in terms of climate resilience. Considering the occurrence of extreme climate events and increasing demand for implementing climate adaptation strategies, the study highlights the importance of improving energy system models to consider future climate variations including extreme events to identify climate resilient energy transition pathways.

Decadal Changes in Meridional Overturning Circulation in the East Sea (Sea of Japan)

AbstractMeridional overturning circulation (MOC) is vital to distributing heat, freshwater, and dissolved matter in semienclosed deep marginal seas such as the East Sea (ES) (Sea of Japan). As our understanding of the ES MOC remains incomplete, we attempted to fill this research gap. We analyzed the ES MOC and its decadal change (1993–2012), employing Hybrid Coordinate Ocean Model (HYCOM) global reanalysis. We found that the ES MOC, consisting of two counterrotating overturning cells in the late 1990s, changed into a single full-depth cell in the 2000s and reverted to two cells in the 2010s. The decadal change relates to weakening of the southward western boundary current at the intermediate layer and northward eastern boundary currents at the deep abyssal layer. We propose that surface warming and salinification favored reduced intermediate water formation and enhanced bottom water formation in the northwestern ES in the 2000s and were, therefore, key to the decadal change. Conditions unfavorable to intermediate water formation and favorable to bottom water formation in the winters of the 2000s, compared with the late 1990s, enhanced northward (westward) Ekman transport in the southern (northeastern) ES, successive advection of surface warm, saline water into water formation areas, and air–sea heat and freshwater exchanges linked to the January Arctic Oscillation. Our results indicated that the ES MOC is sensitive to both external atmospheric forcing and internal ES processes, which have implications for significant changes in the response of other marginal seas and global oceans to future climate variability.

Vulnerability of Water Resources to Climate Change: Adaptation and Resilience Strategies for Sustainable Development in Nigeria

Nigeria faces inexorable climate change in recent times. This phenomenon will have a profound effect on the long-term sustainable socio-economic development and is also likely to jeopardize achievement of economic development of the country. All economic and social sectors will be adversely affected. The water resources sector is one that will be strongly impacted by climate change. Against a background of increasing demand for potable water, sea-level rise may lead to flooding of lowlands and seawater intrusion into coastal aquifers, while variability in climate may see more intense rainstorms resulting both in increased run-off leading to increased flooding and reduced recharge leading to aquifer depletion. Such impacts are already having negative ripple effects on other vital aspects of the economy such as the tourism, recreational, agricultural and industrial sectors. Unfortunately, adequate management of water resources in Nigeria is sorely lacking. Extensive studies to quantify the likely impacts of future climate change and climate variability on water resources in Nigeria are not available. In many cases, baseline data which may be used to track changes are sparse or non-existent. The impacts of climate change and economic value of water resources will form the basis for the development of adaptation strategies with regards to the sustainable management of regional and national water resources. This paper therefore explores the probable effect climate change will have on water resources in Nigeria, the fall-out from these effects and strategies for mitigating potential negative impacts for sustainable development.

Climate Variability and Change in Western U.S. Rangelands

We examine variability and change components of precipitation and minimum and maximum daily temperatures, and the derived variables potential evapotranspiration (PET) and the Palmer Drought Severity Index (PDSI), over rangelands in the region 30-50N, 100- 125W. We focus on areas administered by the U.S. Bureau of Land Management (BLM) and Bureau of Indian Affairs (BIA), with a view toward understanding how future climate variations may affect ecosystems, and ultimately, grazing on these lands. Based on an analysis of the annual precipitation cycle we adopt a three-season partition for the year, classifying land areas by season of maximum precipitation; this yields a coherent subregional map. Masking with a combined BLM/BIA footprint, we find that in all subregions both tmin and tmax have increased in response to anthropogenic forcing, the rate being generally greater for tmax. Significant precipitation trends are not detected, whereas PET exhibits significant upward trends in all regions. While PET-normalized precipitation, as well as PDSI, do not exhibit significant trends individually (by variable and region), the fact that most trend downward nevertheless suggests a systematic drying. We conclude that temperature constitutes the principal detectable control on hydroclimatic changes in rangelands within the study area. Although ecosystem responses may be complex, future temperature increases are expected generally to reduce soil water availability. The unforced component of variability isinvestigated with respect to several key climate indices on both interannual and decadal time scales.

The Role of Engineers in Combating the Effect of Climate Change in Africa

This paper presents an overview of the effects of global warming in Africa as it affects our environment. The challenges of climate change were discussed. The paper focuses further on future climate change and variability and their impact on key sectors: water, food security and agriculture, health, and biodiversity and ecosystems. Finally, the paper summarizes the role of engineers in combating climate change, in a bid to control and reduce global warming around the world.

Spatial distribution and ecological niche modelling of <i>Triplochiton scleroxylon</i> K. Schum., in the Guineo-Congolese region of Benin (West Africa)

Triplochiton sleroxylon (samba) is a West and Central African forest species of high socio-economic value which is increasingly threatened by anthropogenic pressures from various sources. The aim of this study was to determine the impact of climate change on the spatial distribution of Triplochiton sleroxylon in the Guineo-Congolese region of Benin. All of 2311 occurrence data of this species were combined with current and future climate variables in the Maxent program under RCP scenarios 4.5 and 8.5 by 2055. Analysis of the spatial pattern of Triplochiton scleroxylon revealed an aggregative distribution between 1m and 7 m distance. But for a distance between 0 and 1 m and more than 7 m, the spatial pattern revealed a random spatial distribution. Under current climatic conditions, 45.17% of the study area of the Guineo-Congolese region in Benin and 61.69% of the one of protected areas are currently very suitable for the cultivation and conservation of samba. Projections to 2055 indicate a significant increase in the area of these habitats for the two scenarios used. These results show that the current and future climatic conditions of the Guineo-Congolese region in Benin remain favourable for the cultivation and conservation of this species. Unfortunately, outside protected areas, these favourable habitats are occupied by settlements and fields. Taking these results into account could effectively contribute to the sustainable conservation of this species in Benin.
 © 2020 International Formulae Group. All rights reserved.
 Keywords: Climate change, Maxent program, niche modelling, aggregative distribution, Triplochiton scleroxylon, Benin

Assessment of future climate variability and potential adaptation strategies on yield of peanut and Kharif rice in eastern India

Temperature and CO2 are the two most important climate parameters that affect crop yield directly. In this study, the impact of these two parameters on the productivity of peanut and rice under the sub-humid and sub-tropical condition of Eastern India were assessed using experimental data and the DSSAT v4.5 CROPGRO-Peanut and CERES-Rice model. Experimental results of peanut and rice with four sowing dates of each were used as the baseline scenarios. The future weather data from the CSIRO-Mk3–6.0 model for RCP 4.5 and 8.5 was used to the peanut and rice crop model to simulate the yield using future weather data for the periods 2020, 2050, and 2080, and change in yield was compared with the baseline (1980–2013) at Kharagpur, West Bengal, India. The results reveal that rising temperature has negative effect on the growth and developmental phases of crop, and it brings early flowering. Concurrently, increase in temperature causes reduction of crop yield due to pollen sterility and poor pollen growth during reproductive growth stage. The CO2 concentrations used in the model, as projected by IPCC, were 390, 420, 530, and 650 ppm for the years 1980–2013 (baseline), 2020, 2050, and 2080, respectively. However, simulation was made using the model for percent change in mean temperature of 3.36 °C for 2020, 7.59 °C for 2050, and 10.4 °C for 2080. The model simulation reveals that elevated CO2 concentration of 420, 530 and 650 ppm showed gradual increase in the grain yield and biomass yield with shifting in sowing dates for peanut crop. On the other hand, for rice crop, though the crop yield increases gradually, the total biomass yield would reduce in future climate change scenario.

Quantifying the impacts of climate change and extreme climate events on energy systems

Climate induced extreme weather events and weather variations will affect both the demand of energy and the resilience of energy supply systems. The specific potential impact of extreme events on energy systems has been difficult to quantify due to the unpredictability of future weather events. Here we develop a stochastic-robust optimization method to consider both low impact variations and extreme events. Applications of the method to 30 cities in Sweden, by considering 13 climate change scenarios, reveal that uncertainties in renewable energy potential and demand can lead to a significant performance gap (up to 34% for grid integration) brought by future climate variations and a drop in power supply reliability (up to 16%) due to extreme weather events. Appropriate quantification of the climate change impacts will ensure robust operation of the energy systems and enable renewable energy penetration above 30% for a majority of the cities.