Holocene hydroclimate changes in continental Croatia recorded in speleothem δ13C and δ18O from Nova Grgosova Cave

The Holocene ◽  
2021 ◽  
pp. 095968362110191
Author(s):  
Maša Surić ◽  
Andrea Columbu ◽  
Robert Lončarić ◽  
Petra Bajo ◽  
Neven Bočić ◽  
...  
Keyword(s):  
Global Climate ◽  
Precipitation Amount ◽  
Soil Microbial Activity ◽  
Vapor Source ◽  
Global Climate Changes ◽  
Agricultural Revolution ◽  
Precipitation Decrease ◽  
Precipitation Seasonality ◽  
Vegetation Activity ◽  
The Impact

We present the first stable isotope (δ13C and δ18O) speleothem record from continental Croatia retrieved from two coeval stalagmites from Nova Grgosova Cave. U-Th dates constrain the stalagmite growth history from 10 ka to the present, revealing coeval growth between 7.8 and 5.6 ka. We interpret δ18O as an autumn/winter hydrological proxy related to changes of vapor source, precipitation amount, and/or seasonal rainfall distribution, while δ13C predominantly responds to spring/summer vegetation status and soil microbial activity. We identify several centennial to millennial-scale hydroclimate oscillations during this period that result from multiple forcing factors. Along with amount and source effect, it appears that some centennial variations were governed also by seasonal moisture balance. From 9.2 to 8.8 ka BP, the local environmental setting was characterized by enhanced vegetation activity, while during the 8.2 ka event the main feature was a change in precipitation seasonality. The most prominent change, identified in both δ13C records, is a sudden decline of vegetation and soil biological activity around 7.4 ka, indicating a precipitation decrease at a time of maximum plant growth in spring and summer and likely also reduced precipitation in autumn and winter. Although small in magnitude in these speleothems, a peak in δ18O and δ13C values at 4.3–4.1 ka suggests that both summer and winter conditions were substantially drier during the 4.2 ka event, in accordance with increased Mediterranean aridity and consistent with other global climate changes reported at this time. Compared to the present North Atlantic Oscillation (NAO) influence, we assume that millennial Holocene NAO-like variations were persistent through the Holocene via their effect on modifying local/regional air temperature, vapor origin, and inter- and intrannual precipitation distribution. Anthropogenic deforestation, which was the first major human impact on the environment during the Neolithic agricultural revolution, is excluded as a leading factor in δ13C variability since the first sedentary settlements were established further to the east in more arable locations along river valleys. However, the impact of intensive mining around the cave site during the last millennium is evident, with substantial deforestation driving an increase in δ13C.

scholarly journals Assessing the impact of global climate changes on irrigated wheat yields and water requirements in a semi-arid environment of Morocco

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Elhoussaine Bouras ◽  
Lionel Jarlan ◽  
Said Khabba ◽  
Salah Er-Raki ◽  
Alain Dezetter ◽  
...  
Keyword(s):  
Global Climate ◽  
Regional Climate ◽  
Arid Environment ◽  
Water Requirements ◽  
Global Climate Changes ◽  
Development Cycle ◽  
Aquacrop Model ◽  
Irrigated Wheat ◽  
Fertilizing Effect ◽  
The Impact

AbstractThe present work aims to quantify the impact of climate change (CC) on the grain yields of irrigated cereals and their water requirements in the Tensift region of Morocco. The Med-CORDEX (MEDiterranean COordinated Regional Climate Downscaling EXperiment) ensemble runs under scenarios RCP4.5 (Representative Concentration Pathway) and RCP8.5 are first evaluated and disaggregated using the quantile-quantile approach. The impact of CC on the duration of the main wheat phenological stages based on the degree-day approach is then analyzed. The results show that the rise in air temperature causes a shortening of the development cycle of up to 50 days. The impacts of rising temperature and changes in precipitation on wheat yields are next evaluated, based on the AquaCrop model, both with and without taking into account the fertilizing effect of CO2. As expected, optimal wheat yields will decrease on the order of 7 to 30% if CO2 concentration rise is not considered. The fertilizing effect of CO2 can counterbalance yield losses, since optimal yields could increase by 7% and 13% respectively at mid-century for the RCP4.5 and RCP8.5 scenarios. Finally, water requirements are expected to decrease by 13 to 42%, mainly in response to the shortening of the cycle. This decrease is associated with a change in temporal patterns, with the requirement peak coming two months earlier than under current conditions.

scholarly journals Comparison of the Impact of Global Climate Changes and Urbanization on Summertime Future Climate in the Tokyo Metropolitan Area

2012 ◽  
Vol 51 (8) ◽  
pp. 1441-1454 ◽  
Author(s):  
Sachiho A. Adachi ◽  
Fujio Kimura ◽  
Hiroyuki Kusaka ◽  
Tomoshige Inoue ◽  
Hiroaki Ueda
Keyword(s):  
Climate Change ◽  
Metropolitan Area ◽  
Global Climate Change ◽  
Temperature Increase ◽  
Climate Changes ◽  
Global Climate ◽  
Local Climate ◽  
Tokyo Metropolitan Area ◽  
Global Climate Changes ◽  
The Impact

AbstractIn this study, the impact of global climate change and anticipated urbanization over the next 70 years is estimated with regard to the summertime local climate in the Tokyo metropolitan area (TMA), whose population is already near its peak now. First, five climate projections for the 2070s calculated with the aid of general circulation models (GCMs) are used for dynamical downscaling experiments to evaluate the impact of global climate changes using a regional climate model. Second, the sensitivity of future urbanization until the 2070s is examined assuming a simple developing urban scenario for the TMA. These two sensitivity analyses indicate that the increase in the surface air temperature from the 1990s to the 2070s is about 2.0°C as a result of global climate changes under the A1B scenario in the Intergovernmental Panel on Climate Change’s Special Report on Emissions Scenarios (SRES) and about 0.5°C as a result of urbanization. Considering the current urban heat island intensity (UHII) of 1.0°C, the possible UHII in the future reaches an average of 1.5°C in the TMA. This means that the mitigation of the UHII should be one of the ways to adapt to a local temperature increase caused by changes in the future global climate. In addition, the estimation of temperature increase due to global climate change has an uncertainty of about 2.0°C depending on the GCM projection, suggesting that the local climate should be projected on the basis of multiple GCM projections.

Temperature decrease through the Eocene-Oligocene transition controls eco-hydrologic shifts in Central Asia

2020 ◽  
Author(s):  
Alexander Rohrmann ◽  
Guillaume Dupont-Nivet ◽  
Michael Hren ◽  
Dirk Sachse ◽  
Niels Meijer ◽  
...  
Keyword(s):  
Central Asia ◽  
Climate Model ◽  
Global Climate ◽  
Global Climate Model ◽  
Temperature Drop ◽  
Precipitation Amount ◽  
Central China ◽  
Broad Leaf ◽  
Xining Basin ◽  
The Impact

<p>At ca. 34 Ma the Eocene-Oligocene transition (EOT) marks the shift from greenhouse conditions during the Eocene to the icehouse of the Oligocene and was the most pronounced cooling event during the Cenozoic. This event is well documented in marine records with a significant increase in benthic foraminifera δ18O values suggesting a 5°C cooling in air temperature through the EOT. Instead, the few but growing number of terrestrial records suggest a much larger cooling of 4-9°C. Yet, details regarding the exact timing of cooling and ensuing terrestrial changes in climate, hydrology, and ecology are sparse. Here, we investigate the impact of the EOT cooling event and associated climatic changes on the hydrology and vegetation in central China. We use stable isotopes of hydrogen (δD<sub>wax</sub>) and carbon (δ<sup>13</sup>C<sub>wax</sub>) from leaf-waxes, a paleo-hydrology proxy obtained from organic material in sedimentary rocks, in combination with pollen data from a continuous well-dated, high-resolution sedimentary section from the Xining Basin in NE Tibet (36°42' N, 101°43' E). We then compare our results to a fully-coupled, global climate model (GCM) simulating the pre- and post-EOT conditions in central Asia.</p><p>The obtained δD<sub>wax </sub>record ranges between -160 to -190‰ and shows a complex two-step transition through the EOT with a rapid initial drop of -30‰ from 33.9 to 33.7 Ma, a recovery to pre-EOT values between 33.7 to 33.4 Ma and a second drop similar in magnitude as the first one. In contrast, δ<sup>13</sup>C<sub>wax</sub> values remain unchanged at -29 to -28‰ through the EOT. The GCM indicates a difference in temperature throughout the year between pre- and post-EOT runs of 8-9°C at the Xining Basin with change in seasonality due to the collapse of the pre-EOT wet spring season, yielding mainly autumn precipitation after the transition. The overall precipitation amount remained in both simulations dry with < 500 mm/yr. The combined results show that the region experienced: (a) a significant temperature drop of 8-9°C through the EOT being the first-order control on the records decrease in δD<sub>wax </sub> (1-2 ‰ per 1°C in mid-latitudes and up-to 5 ‰ per 1°C in higher latitudes) through the EOT; (b) constant bioproductivity and/or similar water-use efficiency within plants displayed by unchanged δ<sup>13</sup>C<sub>wax </sub>values; (c) a changeover from a “warm-wet” desert abundant in Nitraria and Ephedra shrubs to a “temperate” desert with an expansion of conifers and broad-leaf trees in the higher-elevation hinterlands. We interpret that this change in seasonality and cooler EOT temperatures reduced the plant’s overall transpirational pressure, contributing to the spread of conifers and broad-leaf trees after the EOT under regionally new hydrologic conditions.</p>

scholarly journals Evaluation of the influence of climate change on the productivity of millet in the central part of Ukraine

2018 ◽  
pp. 35-41
Author(s):  
N. V. Danilova
Keyword(s):  
Climate Change ◽  
Global Climate ◽  
Perennial Grass ◽  
Arable Land ◽  
Precipitation Amount ◽  
Early Spring ◽  
Climatic Conditions ◽  
Eating Quality ◽  
Winter Crops ◽  
The Impact

Climate change is a change of climatic conditions in the global atmosphere and on the Earth in general (or within its individual zones or territories) caused directly or indirectly due by the human activity on the planet, which are overlaid on the natural climatic variations (fluctuations) and ob-served during comparable periods of time.    Both the climate of Ukraine and the global climate are changing, but warming within our terri-tory progresses even faster than in other regions of the Northern Hemisphere. Ukraine in general and southern regions in particular are becoming increasingly vulnerable to climate change – droughts, extremely high temperatures, inefficient precipitation, reduced irrigated area cause of precipitation amount and regime, severer and more long-lasting droughts, reduced water availability. The majority of arable land in Ukraine are located in zones of unstable and insufficient humidity, it is quite possible that for plant growing, especially for growing winter crops and early spring crops, climate change will rather have a positive effect than negative one. Among the main types of cereals millet is the most common one. It is valuable for its groats, which is known by its high eating quality. Millet as a fast-growing crop having a certain agrotechnical importance: it is used as a backup crop for re-sowing dead winter crops and is suitable for stubble and post-harvest sowing, it also can be used as a cover culture for perennial grass. Millet is one of the most drought-resistant and heat-resistant crops. It is able to withstand heat injuries which is very important in arid areas and during dry years, when other grain crops have reduced yield. Millet suffers less from pests and diseases than other crops. The task was to evaluate the agro-climatic conditions of millet crops formation in the central part of Ukraine under conditions of climate change. The study of the impact of climate change on the formation of millet productivity for different time intervals was performed by comparing the data of the RCP scenario and the average long-term climatic and agro-climatic parameters. The in-fluence of agroclimatic conditions on the dynamics of increase of agroecological yield of different levels is also assessed.

scholarly journals A Climatological Interpretation of Precipitation δ18O across Siberia and Central Asia

Water ◽  
2020 ◽  
Vol 12 (8) ◽  
pp. 2132 ◽  
Author(s):  
Tao Wang ◽  
Ting-Yong Li ◽  
Jian Zhang ◽  
Yao Wu ◽  
Chao-Jun Chen ◽  
...  
Keyword(s):  
Water Vapor ◽  
Temperature Effect ◽  
Central Asia ◽  
Global Climate ◽  
Ice Core ◽  
Precipitation Amount ◽  
Weighted Average ◽  
Global Network ◽  
Vapor Source ◽  
Precipitation Δ18o

Siberia and Central Asia are located at middle to high latitudes, encompassing a large landlocked area of the Eurasian continent and vast tracts of permafrost, which are sensitive to global climate change. Here, we investigated the data from 15 Global Network of Isotopes in Precipitation (GNIP) stations to clarify the relationship between precipitation δ18O (δ18OP) and the local temperature and precipitation amount on the monthly, seasonal, and annual timescales. Three main conclusions as following: (1) On the monthly time scale, the variation in δ18OP is mainly controlled by the “temperature effect”. (2) The weighted average value of precipitation δ18O (δ18Ow) exhibited “temperature effect” over 60° N–70° N. However, δ18Ow was dominated by multiple factors from 40° N to 60° N (e.g., the North Atlantic Oscillation (NAO) and water vapor source changes). (3) The variations of δ18OW can be attributed to the changes in pathway of the westerly dominated by the NAO at annual timescale. Therefore, it is possible to reconstruct the histories of past atmospheric circulations and water vapor sources in this region via δ18O in geologic archives, e.g., speleothem and ice core records.

scholarly journals Estimation of the Effect of Changes in Forest Associations on Runoff Processes in Basins: Case Study in the Hron and Topľa River Basins

2016 ◽  
Vol 24 (3) ◽  
pp. 1-7 ◽  
Author(s):  
Peter Rončák ◽  
Kamila Hlavčová ◽  
Tamara Látková
Keyword(s):  
Land Use ◽  
Global Climate ◽  
River Basins ◽  
Distributed Model ◽  
Model Parameters ◽  
Climate Data ◽  
Global Climate Changes ◽  
Wetspa Model ◽  
Runoff Regime ◽  
The Impact

Abstract Distributed rainfall-runoff model simulations are often used to evaluate the impact of changes on the generation of runoff. These models have the advantage of reflecting the effects of land use on spatially distributed model parameters. The article deals with changes in forest associations as a result of global climate changes. In this article the WetSpa model was used for estimating the impact of forest changes on the runoff regime in the Hron and Topla river basins, with an emphasis on the parameterization of the land cover properties in the runoff simulations. The parameters of the model were estimated using climate data and three digital map layers: a land-use map, soil map and digital elevation model. This work contains two land use change scenarios of forest associations and also two scenarios of global climate change. Both types of scenarios of changes were prepared, and the runoff under the new conditions was simulated.

scholarly journals Analysis of Global Warming’s Influence on the Dimensioning of Borehole Heat Exchangers at a Climate-Exposed Site

Processes ◽  
2021 ◽  
Vol 9 (3) ◽  
pp. 501
Author(s):  
Antonín Kunz ◽  
Martin Klempa ◽  
Petr Bujok ◽  
Dawid Piotrowski
Keyword(s):  
Climate Changes ◽  
Global Climate ◽  
Energy Potential ◽  
Pump System ◽  
Heat Pump System ◽  
Exposed Site ◽  
Global Climate Changes ◽  
Sustainable Performance ◽  
Using Data ◽  
The Impact

A borehole heat exchanger (BHE) presents the most reliable source of geothermal energy for any object where the heat pump system is to be installed. The main objective of BHE optimization in a specific rock massive and for calculated heat consumption is to design a BHE with proper capacity and sustainable performance. One of the most important inputs for the preparation of such a model is the average outer air temperature on the site during the year. While the properties of the local rock massive are from the heat project lifetime view (tens of years) stable, the local average outer temperature fluctuates according to global climate changes. This article presents a study of the impact of climate changes on the dimensioning process of a BHE and consequently on its performance using data from a real installation at a highly climate-exposed site in the Czech Republic. During the dimensioning of a BHE, this study could help to better quantify the objective risks that result from climate changes. However, the results of this study show that the currently calculated impact of an increase in outer temperature is not crucial, but it is advisable to take this new fact into account during the design and dimensioning process, especially for large installations. To study the ground in terms of usable energy potential at climate-exposed locations properly, the available data were critically analyzed and the results were then synthesized in an appropriate way for the needs of the data simulations.

An Empirical Evidence of Global Warming and its impact on India’s Agricultural Production

2019 ◽  
Vol 118 (10) ◽  
pp. 107-116
Author(s):  
Dr.P. Prema ◽  
Ms.R. Kanchana
Keyword(s):  
Climate Change ◽  
Agricultural Production ◽  
Climate Changes ◽  
Agricultural Land ◽  
Global Climate ◽  
Large Country ◽  
Climatic Zones ◽  
Global Climate Changes ◽  
Different Types ◽  
The Impact

India is a large country with all types of climates and different kinds of soil requiring different types of farming. Most of the agricultural land in India is dependent on rainfall for irrigation. India has about 15 Agro-climatic zones with different types of farming methods and crops. As most of the population is dependent on agriculture and two-third of the country depend on monsoon rains to aid in agriculture, any change in frequency of the rains will affect these areas critically. Assessment of the effects of global climate changes on agriculture might help to properly anticipate and adapt farming to maximize agricultural production. At the same time agriculture has been shown significant effects on climate change, primarily through the production and release of greenhouse gases such as carbon dioxide, methane, and nitrous oxide. The impact of climate change on agriculture could result in problems like food security and may threaten the livelihood on which much of the population depends.

Paroxysmal Deccan Eruptions linked to End-Cretaceous Mass Extinction

2021 ◽  
Author(s):  
Thierry Adatte ◽  
Gerta Keller ◽  
Jorge E. Spangenberg ◽  
Paula Mateo ◽  
Jahnavi Punekar ◽  
...  
Keyword(s):  
Mass Extinction ◽  
Environmental Changes ◽  
Global Climate ◽  
Volcanic Eruptions ◽  
Mass Extinctions ◽  
Deccan Volcanism ◽  
Time Resolved ◽  
Global Climate Changes ◽  
Chicxulub Impact ◽  
The Impact

<p>The Chicxulub impact in Mexico and Deccan volcanism in India are both linked to the end-Cretaceous mass extinction but the relative timing of the impact, volcanic eruptions, and environmental changes remain controversial, precluding a full assessment of their respective roles. Mercury anomalies within the stratigraphic record have recently been proposed as atmospheric fallout of continental large igneous provinces (LIPs), and these anomalies are associated with all five major mass extinctions in Earth’s history. If this proxy is robust, it could provide a record of volcanism directly correlated to mass extinctions and in the case of the End-extinction, the Chicxulub impact. To test this hypothesis, we analyzed mercury in the late Maastrichtian from the base of C29r to the Cretaceous-Paleogene boundary (KPB) n the astronomically tuned Elles section in Tunisia, and correlate this chemostratigraphic record with recent high-precision U-Pb geochronology of Deccan volcanism. Our results support that Hg is a robust indicator of LIP volcanism, and directly links Deccan volcanism to rapid global climate changes, ocean acidification and increasing environmental stress during the last 320-340 kyr of the Maastrichtian. Furthermore, our time-resolved Hg record and U-Pb resolved eruption volumes reveal paroxysmal volcanic eruptions (~30% by volume) during the final 35 kyr leading up to the KPB mass extinction.</p>

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