scholarly journals The Capitanian Minimum: A Unique Sr Isotope Beacon of the Latest Paleozoic Seawater

2021 ◽  
Vol 9 ◽  
Author(s):  
Tomomi Kani ◽  
Yukio Isozaki

The long-term trend in the Paleozoic seawater 87Sr/86Sr was punctuated by a unique episode called the “Capitanian minimum” at the end of the Guadalupian (Permian; ca. 260 Ma). This article reviews the nature and timing of this major turning point in seawater Sr isotope composition (87Sr/86Sr, δ88Sr) immediately before the Paleozoic-Mesozoic boundary (ca. 252 Ma). The lowest value of seawater 87Sr/86Sr (0.7068) in the Capitanian and the subsequent rapid increase at an unusually high rate likely originated from a significant change in continental flux with highly radiogenic Sr. The assembly of the supercontinent Pangea and its subsequent mantle plume-induced breakup were responsible for the overall secular change throughout the Phanerozoic; nonetheless, short-term fluctuations were superimposed by global climate changes. Regarding the unidirectional decrease in Sr isotope values during the early-middle Permian and the Capitanian minimum, the suppression of continental flux was driven by the assembly of Pangea and by climate change with glaciation. In contrast, the extremely rapid increase in Sr isotope values during the Lopingian-early Triassic was induced by global warming. The unique trend change in seawater Sr isotope signatures across the Guadalupian-Lopingian Boundary (GLB) needs to be explained in relation to the unusual climate change associated with a major extinction around the GLB.

Author(s):  
D. G. Galkin

The goal of the article is to work out recommendations aimed at providing sustainability of agriculture development on the level of national economy in conditions of changing climate. The agriculture development within the frames of traditional approach can be studied in two aspects: as a sector subjected to the global climate change impact; as a sector promoting climate change due to greenhouse gas emission. The authors showed that in regard to present trends scientific recommendations aimed at agriculture adaptation to climate changes are the most significant for Russia. On the basis of provided concepts they identified key lines in the said adaptation: to develop innovation connected with adaptation to consequences of climate changes; to upgrade the system of agro-insurance; to use methods of organic food production; to monitor and appraise adaptation of agriculture to climate changes; to introduce strategic planning of sustainable development and location of agricultural production. These lines should be realized on the basis of integrity, strategic orientation and scientific support of agricultural production. These lines can stabilize the level of key parameters of the sector in the long-term perspective.


2019 ◽  
pp. 79-95
Author(s):  
N.E. Terentiev

Based on the latest data, paper investigates the dynamics of global climate change and its impact on economic growth in the long-term. The notion of climate risk is considered. The main directions of climate risk management policies are analyzed aimed, first, at reducing anthropogenic greenhouse gas emissions through technological innovation and structural economic shifts; secondly, at adaptation of population, territories and economic complexes to the irreparable effects of climate change. The problem of taking into account the phenomenon of climate change in the state economic policy is put in the context of the most urgent tasks of intensification of long-term socio-economic development and parrying strategic challenges to the development of Russia.


The Condor ◽  
2021 ◽  
Author(s):  
Natália Stefanini Da Silveira ◽  
Maurício Humberto Vancine ◽  
Alex E Jahn ◽  
Marco Aurélio Pizo ◽  
Thadeu Sobral-Souza

Abstract Bird migration patterns are changing worldwide due to current global climate changes. Addressing the effects of such changes on the migration of birds in South America is particularly challenging because the details about how birds migrate within the Neotropics are generally not well understood. Here, we aim to infer the potential effects of future climate change on breeding and wintering areas of birds that migrate within South America by estimating the size and elevations of their future breeding and wintering areas. We used occurrence data from species distribution databases (VertNet and GBIF), published studies, and eBird for 3 thrush species (Turdidae; Turdus nigriceps, T. subalaris, and T. flavipes) that breed and winter in different regions of South America and built ecological niche models using ensemble forecasting approaches to infer current and future potential distributions throughout the breeding and wintering periods of each species. Our findings point to future shifts in wintering and breeding areas, mainly through elevational and longitudinal changes. Future breeding areas for T. nigriceps, which migrates along the Andes Mountains, will be displaced to the west, while breeding displacements to the east are expected for the other 2 species. An overall loss in the size of future wintering areas was also supported for 2 of the species, especially for T. subalaris, but an increase is anticipated for T. flavipes. Our results suggest that future climate change in South America will require that species shift their breeding and wintering areas to higher elevations in addition to changes in their latitudes and longitude. Our findings are the first to show how future climate change may affect migratory birds in South America throughout the year and suggest that even closely related migratory birds in South America will be affected in different ways, depending on the regions where they breed and overwinter.


2014 ◽  
Vol 28 (1) ◽  
pp. 66-85 ◽  
Author(s):  
Chung-Chieh Wang ◽  
Bo-Xun Lin ◽  
Cheng-Ta Chen ◽  
Shih-How Lo

Abstract To quantify the effects of long-term climate change on typhoon rainfall near Taiwan, cloud-resolving simulations of Typhoon (TY) Sinlaku and TY Jangmi, both in September 2008, are performed and compared with sensitivity tests where these same typhoons are placed in the climate background of 1950–69, which is slightly cooler and drier compared to the modern climate of 1990–2009 computed using NCEP–NCAR reanalysis data. Using this strategy, largely consistent responses are found in the model although only two cases are studied. In control experiments, both modern-day typhoons yield more rainfall than their counterpart in the sensitivity test using past climate, by about 5%–6% at 200–500 km from the center for Sinlaku and roughly 4%–7% within 300 km of Jangmi, throughout much of the periods simulated. In both cases, the frequency of more-intense rainfall (20 to >50 mm h−1) also increases by about 5%–25% and the increase tends to be larger toward higher rain rates. Results from the water budget analysis, again quite consistent between the two cases, indicate that the increased rainfall from the typhoons in the modern climate is attributable to both a moister environment (by 2.5%–4%) as well as, on average, a more active secondary circulation of the storm. Thus, a changing climate may already have had a discernible impact on TC rainfall near Taiwan. While an overall increase in TC rainfall of roughly 5% may not seem large, it is certainly not insignificant considering that the long-term trend observed in the past 40–50 yr, whatever the causes might be, may continue for many decades in the foreseeable future.


Author(s):  
Jiban Mani Poudel

In the 21st century, global climate change has become a public and political discourse. However, there is still a wide gap between global and local perspectives. The global perspective focuses on climate fluctuations that affect the larger region; and their analysis is based on long-term records over centuries and millennium. By comparison, local peoples’ perspectives vary locally, and local analyses are limited to a few days, years, decades and generations only. This paper examines how farmers in Kirtipur of Kathmandu Valley, Nepal, understand climate variability in their surroundings. The researcher has used a cognized model to understand farmers’ perception on weather fluctuations and climate change. The researcher has documented several eyewitness accounts of farmers about weather fluctuations which they have been observing in a lifetime. The researcher has also used rainfall data from 1970-2009 to test the accuracy of perceptions. Unlike meteorological analyses, farmers recall and their understanding of climatic variability by weather-crop interaction, and events associating with climatic fluctuations and perceptions are shaped by both physical visibility and cultural frame or belief system.DOI: http://dx.doi.org/10.3126/hn.v11i1.7200 Hydro Nepal Special Issue: Conference Proceedings 2012 pp.30-34


Author(s):  
Robert A. Berner

The cycle of carbon is essential to the maintenance of life, to climate, and to the composition of the atmosphere and oceans. What is normally thought of as the “carbon cycle” is the transfer of carbon between the atmosphere, the oceans, and life. This is not the subject of interest of this book. To understand this apparently confusing statement, it is necessary to separate the carbon cycle into two cycles: the short-term cycle and the long-term cycle. The “carbon cycle,” as most people understand it, is represented in figure 1.1. Carbon dioxide is taken up via photosynthesis by green plants on the continents or phytoplankton in the ocean. On land carbon is transferred to soils by the dropping of leaves, root growth, and respiration, the death of plants, and the development of soil biota. Land herbivores eat the plants, and carnivores eat the herbivores. In the oceans the phytoplankton are eaten by zooplankton that are in turn eaten by larger and larger organisms. The plants, plankton, and animals respire CO2. Upon death the plants and animals are decomposed by microorganisms with the ultimate production of CO2. Carbon dioxide is exchanged between the oceans and atmosphere, and dissolved organic matter is carried in solution by rivers from soils to the sea. This all constitutes the shortterm carbon cycle. The word “short-term” is used because the characteristic times for transferring carbon between reservoirs range from days to tens of thousands of years. Because the earth is more than four billion years old, this is short on a geological time scale. As the short-term cycle proceeds, concentrations of the two principal atmospheric gases, CO2 and CH4, can change as a result of perturbations of the cycle. Because these two are both greenhouse gases—in other words, they adsorb outgoing infrared radiation from the earth surface—changes in their concentrations can involve global warming and cooling over centuries and many millennia. Such changes have accompanied global climate change over the Quaternary period (past 2 million years), although other factors, such as variations in the receipt of solar radiation due to changes in characteristics of the earth’s orbit, have also contributed to climate change.


2013 ◽  
Vol 9 (2) ◽  
pp. 687-697 ◽  
Author(s):  
R. Orain ◽  
V. Lebreton ◽  
E. Russo Ermolli ◽  
A.-M. Sémah ◽  
S. Nomade ◽  
...  

Abstract. The palaeobotanical record of early Palaeolithic sites from Western Europe indicates that hominins settled in different kinds of environments. During the "mid-Pleistocene transition (MPT)", from about 1 to 0.6 Ma, the transition from 41- to 100-ka dominant climatic oscillations, occurring within a long-term cooling trend, was associated with an aridity crisis which strongly modified the ecosystems. Starting from the MPT the more favourable climate of central and southern Italy provided propitious environmental conditions for long-term human occupations even during the glacial times. In fact, the human strategy of territory occupation was certainly driven by the availabilities of resources. Prehistoric sites such as Notarchirico (ca. 680–600 ka), La Pineta (ca. 600–620 ka), Guado San Nicola (ca. 380–350 ka) or Ceprano (ca. 345–355 ka) testify to a preferential occupation of the central and southern Apennines valleys during interglacial phases, while later interglacial occupations were oriented towards the coastal plains, as attested by the numerous settlements of the Roma Basin (ca. 300 ka). Faunal remains indicate that human subsistence behaviours benefited from a diversity of exploitable ecosystems, from semi-open to closed environments. In central and southern Italy, several palynological records have already illustrated the regional- and local-scale vegetation dynamic trends. During the Middle Pleistocene climate cycles, mixed mesophytic forests developed during the interglacial periods and withdrew in response to increasing aridity during the glacial episodes. New pollen data from the Boiano Basin (Molise, Italy) attest to the evolution of vegetation and climate between MIS 13 and 9 (ca. 500 to 300 ka). In this basin the persistence of high edaphic humidity, even during the glacial phases, could have favoured the establishment of a refuge area for the arboreal flora and provided subsistence resources for the animal and hominin communities during the Middle Pleistocene. This could have constrained human groups to migrate into such a propitious area. Regarding the local climate evolution during the glacial episodes, the supposed displacement from these sites could be linked to the environmental dynamics solely due to the aridity increase, rather than directly to the global climate changes.


Author(s):  
Irvin Alberto Mosquera ◽  
Luis Volnei Sudati Sagrilo ◽  
Paulo Maurício Videiro

Abstract This paper discusses the influence of the climate change in the long-term response of offshore structures. The case studied is a linear single-degree-of-freedom (SDOF) system under environmental load wave characterized by the JONSWAP spectrum. The wave parameter data used in the analyses were obtained from running the wind wave WaveWatch III with wind field input data derived from two Global Climate Models (GCMs): HadGEM2-ES and MRI-CGCM3 considering historical and future greenhouse emissions scenarios. The study was carried out for two locations: one in the North Atlantic and the other in Brazilian South East Coast. Environmental contours have been used to estimate the extreme long-term response. The results suggest that climate change would affect the structure response and its impact is highly depend on the structure location, the global climate model and the greenhouse emissions scenario selected.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
A. P. Silva ◽  
A. H. F. Klein ◽  
A. F. H. Fetter-Filho ◽  
C. J. Hein ◽  
F. J. Méndez ◽  
...  

Abstract Through alteration of wave-generating atmospheric systems, global climate changes play a fundamental role in regional wave climate. However, long-term wave-climate cycles and their associated forcing mechanisms remain poorly constrained, in part due to a relative dearth of highly resolved archives. Here we use the morphology of former shorelines preserved in beach-foredune ridges (BFR) within a protected embayment to reconstruct changes in predominant wave directions in the Subtropical South Atlantic during the last ~ 3000 years. These analyses reveal multi-centennial cycles of oscillation in predominant wave direction in accordance with stronger (weaker) South Atlantic mid- to high-latitudes mean sea-level pressure gradient and zonal westerly winds, favouring wave generation zones in higher (lower) latitudes and consequent southerly (easterly) wave components. We identify the Southern Annular Mode as the primary climate driver responsible for these changes. Long-term variations in interhemispheric surface temperature anomalies coexist with oscillations in wave direction, which indicates the influence of temperature-driven atmospheric teleconnections on wave-generation cycles. These results provide a novel geomorphic proxy for paleoenvironmental reconstructions and present new insights into the role of global multi-decadal to multi-centennial climate variability in controlling coastal-ocean wave climate.


2020 ◽  
Vol 26 (1) ◽  
pp. 65-70 ◽  
Author(s):  
Robbie M. Parks ◽  
James E. Bennett ◽  
Helen Tamura-Wicks ◽  
Vasilis Kontis ◽  
Ralf Toumi ◽  
...  

AbstractTemperatures that deviate from the long-term local norm affect human health, and are projected to become more frequent as the global climate changes1. There are limited data on how such anomalies affect deaths from injuries. In the present study, we used data on mortality and temperature over 38 years (1980–2017) in the contiguous USA and formulated a Bayesian spatio-temporal model to quantify how anomalous temperatures, defined as deviations of monthly temperature from the local average monthly temperature over the entire analysis period, affect deaths from unintentional (transport, falls and drownings) and intentional (assault and suicide) injuries, by age group and sex. We found that a 1.5 °C anomalously warm year, as envisioned under the Paris Climate Agreement2, would be associated with an estimated 1,601 (95% credible interval 1,430–1,776) additional injury deaths. Of these additional deaths, 84% would occur in males, mostly in adolescence to middle age. These would comprise increases in deaths from drownings, transport, assault and suicide, offset partly by a decline in deaths from falls in older ages. The findings demonstrate the need for targeted interventions against injuries during periods of anomalously warm temperatures, especially as these episodes are likely to increase with global climate change.


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