scholarly journals High-precision U-Pb CA-TIMS calibration of Middle Permian to Lower Triassic sequences, mass extinction and extreme climate-change in eastern Australian Gondwana

2015 ◽  
Vol 28 (1) ◽  
pp. 61-81 ◽  
Author(s):  
I. Metcalfe ◽  
J.L. Crowley ◽  
R.S. Nicoll ◽  
M. Schmitz
Keyword(s):  
Climate Change ◽  
High Precision ◽  
Mass Extinction ◽  
Lower Triassic ◽  
Middle Permian ◽  
Extreme Climate

scholarly journals Quantification of impact of climate uncertainty on regional air quality

2008 ◽  
Vol 8 (2) ◽  
pp. 7781-7804 ◽  
Author(s):  
K.-J. Liao ◽  
E. Tagaris ◽  
K. Manomaiphiboon ◽  
C. Wang ◽  
J.-H. Woo ◽  
...  
Keyword(s):  
Climate Change ◽  
Air Quality ◽  
Urban Areas ◽  
Climate Models ◽  
Global Climate Models ◽  
Base Case ◽  
Daily Maximum ◽  
Climate Scenarios ◽  
Extreme Climate ◽  
Regional Air Quality

Abstract. Impacts of uncertain climate forecasts on future regional air quality are investigated using downscaled MM5 meteorological fields from the NASA GISS and MIT IGSM global climate models and the CMAQ model in 2050 in the continental US. Three future climate scenarios: high-extreme, low-extreme and base, are developed for regional air quality simulations. GISS, with the IPCC A1B scenario, is used for the base case. IGSM results, in the form of probabilistic distributions, are used to perturb the base case climate to provide 0.5th and 99.5th percentile climate scenarios. Impacts of the extreme climate scenarios on concentrations of summertime fourth-highest daily maximum 8-h average ozone are predicted to be up to 10 ppbv (about one-eighth of the current NAAQS of ozone) in some urban areas, though average differences in ozone concentrations are about 1–2 ppbv on a regional basis. Differences between the extreme and base scenarios in annualized PM2.5 levels are very location dependent and predicted to range between −1.0 and +1.5 μg m−3. Future annualized PM2.5 is less sensitive to the extreme climate scenarios than summertime peak ozone since precipitation scavenging is only slightly affected by the extreme climate scenarios examined. Relative abundances of biogenic VOC and anthropogenic NOx lead to the areas that are most responsive to climate change. Such areas may find that climate change can significantly offset air quality improvements from emissions reductions, particularly during the most severe episodes.

scholarly journals Impact of recent climate extremes on mosquito-borne disease transmission in Kenya

2021 ◽  
Vol 15 (3) ◽  
pp. e0009182
Author(s):  
Cameron Nosrat ◽  
Jonathan Altamirano ◽  
Assaf Anyamba ◽  
Jamie M. Caldwell ◽  
Richard Damoah ◽  
...  
Keyword(s):  
Climate Change ◽  
Disease Transmission ◽  
Enzyme Linked Immunosorbent Assay ◽  
Mosquito Abundance ◽  
Targeted Interventions ◽  
Extreme Climate Events ◽  
Extreme Climate ◽  
Recent Climate ◽  
Climate Events ◽  
The Impact

Climate change and variability influence temperature and rainfall, which impact vector abundance and the dynamics of vector-borne disease transmission. Climate change is projected to increase the frequency and intensity of extreme climate events. Mosquito-borne diseases, such as dengue fever, are primarily transmitted by Aedes aegypti mosquitoes. Freshwater availability and temperature affect dengue vector populations via a variety of biological processes and thus influence the ability of mosquitoes to effectively transmit disease. However, the effect of droughts, floods, heat waves, and cold waves is not well understood. Using vector, climate, and dengue disease data collected between 2013 and 2019 in Kenya, this retrospective cohort study aims to elucidate the impact of extreme rainfall and temperature on mosquito abundance and the risk of arboviral infections. To define extreme periods of rainfall and land surface temperature (LST), we calculated monthly anomalies as deviations from long-term means (1983–2019 for rainfall, 2000–2019 for LST) across four study locations in Kenya. We classified extreme climate events as the upper and lower 10% of these calculated LST or rainfall deviations. Monthly Ae. aegypti abundance was recorded in Kenya using four trapping methods. Blood samples were also collected from children with febrile illness presenting to four field sites and tested for dengue virus using an IgG enzyme-linked immunosorbent assay (ELISA) and polymerase chain reaction (PCR). We found that mosquito eggs and adults were significantly more abundant one month following an abnormally wet month. The relationship between mosquito abundance and dengue risk follows a non-linear association. Our findings suggest that early warnings and targeted interventions during periods of abnormal rainfall and temperature, especially flooding, can potentially contribute to reductions in risk of viral transmission.

A new faunistic component of the Lower Triassic Panchet Formation of India increases the continental non-archosauromorph neodiapsid record in the aftermath of the end-Permian mass extinction

2021 ◽  
pp. 1-11
Author(s):  
Martín D. Ezcurra ◽  
Saswati Bandyopadhyay ◽  
Kasturi Sen
Keyword(s):  
Mass Extinction ◽  
Lower Triassic ◽  
Maximum Height ◽  
Dorsal Margin ◽  
Early Triassic ◽  
Anterior Portion ◽  
Continental Deposits ◽  
Biotic Recovery ◽  
Patterns And Processes ◽  
Permian Mass Extinction

Abstract The fossil record of Early Triassic diapsids is very important to understand how the end-Permian mass extinction affected ecosystems and the patterns and processes involved in the subsequent biotic recovery. Vertebrate fossil assemblages of continental deposits in current-day South Africa, China, and Russia are the best source of information of this clade during the aftermath of the extinction event. Although considerably less sampled, the Induan continental rocks of the Panchet Formation of the Damodar Basin (eastern India) have also yielded a relatively diverse vertebrate assemblage composed of fishes, temnospondyls, synapsids, and a single proterosuchid taxon. Here, we report on a small isolated diapsid partial ilium (ISIR 1132) from the upper Panchet Formation. This specimen has a distinct morphology compared to other tetrapods that we know, including a shallow emargination on the dorsal margin of the anterior portion of the iliac blade, and ratio between height of iliac blade versus maximum height of iliac acetabulum at level of the dorsalmost extension of supraacetabular crest ≤0.45. Comparisons and a quantitative phylogenetic analysis found ISIR 1132 as a non-archosauromorph neodiapsid. This new specimen expands the reptile diversity in the Panchet Formation as well as for the rest of Gondwana, where Early Triassic non-archosauromorph neodiapsid species are extremely scarce.

Climate change will impact the protective effect of forests against rockfall

2021 ◽  
Author(s):  
Christine Moos ◽  
Antoine Guisan ◽  
Randin Christophe ◽  
Lischke Heike
Keyword(s):  
Climate Change ◽  
Protective Effect ◽  
Natural Disturbance ◽  
High Elevation ◽  
Swiss Alps ◽  
Protective Capacity ◽  
Forest Modelling ◽  
Mountain Areas ◽  
Protective Function ◽  
Extreme Climate

<p>In mountain areas, forests play a crucial role in protecting people and assets from natural hazards, such as rockfall. Their protective effect is strongly influenced by their structure and state, which are expected to be affected by climate change. More frequent drought events, but also changing natural disturbance regimes, may lead to abrupt diebacks of contemporary species followed by a slow reforestation. In this study, we investigated how a changing climate can affect the protective capacity of mountain forests against rockfall. We therefore combined dynamic forest modelling with a detailed rockfall risk analysis at three case study sites in the Western Swiss Alps. Future forest development was simulated for a moderate and an extreme climate scenario for 200 years with the dynamic forest model TreeMig (Lischke et al., 2006). We then calculated rockfall risk for different forest states based on three-dimensional rockfall simulations with RockyFor3D (Dorren 2016). First results indicate that both at high elevation near the tree line (1500-2200 m a.s.l.) as well as at lower elevations (500-1000 m a.s.l.), increasing drought can lead to diebacks of trees and a reduction of tree density and diameters resulting in a substantial loss of the protective function. Depending on the speed of migration of other, more drought tolerant species, this loss can be partially compensated, but a permanent reduction of the protective effect is to be expected at least for an extreme climate scneario due to a reduced basal area of the forest.</p>

Volcanism, Mass Extinction, and Carbon Isotope Fluctuations in the Middle Permian of China

Science ◽  
2009 ◽  
Vol 324 (5931) ◽  
pp. 1179-1182 ◽  
Author(s):  
P. B. Wignall ◽  
Y. Sun ◽  
D. P. G. Bond ◽  
G. Izon ◽  
R. J. Newton ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Mass Extinction ◽  
Middle Permian

scholarly journals Ocean euxinia and climate change “double whammy” drove the Late Ordovician mass extinction

Geology ◽  
2018 ◽  
Vol 46 (6) ◽  
pp. 535-538 ◽  
Author(s):  
Caineng Zou ◽  
Zhen Qiu ◽  
Simon W. Poulton ◽  
Dazhong Dong ◽  
Hongyan Wang ◽  
...  
Keyword(s):  
Climate Change ◽  
Mass Extinction ◽  
Late Ordovician

scholarly journals Rebound from the Permian/Triassic mass extinction: evolutionary paleoecology of sequential early Triassic (Smithian to Spathian) marine paleocommunities

1992 ◽  
Vol 6 ◽  
pp. 261-261
Author(s):  
Jennifer K. Schubert ◽  
David J. Bottjer
Keyword(s):  
Mass Extinction ◽  
Lower Triassic ◽  
Upper Permian ◽  
Early Triassic ◽  
Triassic Boundary ◽  
Biotic Recovery ◽  
The Status ◽  
Life Habits ◽  
Stalked Crinoids ◽  
Permian Triassic Boundary

The Permian/Triassic mass extinction, the most devastating biotic crisis of the Phanerozoic, has aroused considerable scientific interest. However, because research has focused primarily on understanding the magnitude of diversity reduction and causal mechanisms, the nature and timing of biotic recovery in the Early Triassic are still poorly understood. Marine limestones in the Lower Triassic Moenkopi Formation, which disconformably overlies the Upper Permian of southeastern Nevada and southern Utah, provide a rare opportunity to study the aftermath of the mass extinction in shallow water carbonate environments.Two contemporaneous members of the Moenkopi record the first marine incursion from the northwest in the Early Triassic (Smithian), the very sparsely fossiliferous marginal marine Schnabkaib Member in Nevada and southwest Utah, and the Sinbad Limestone in central-southern Utah, a marine unit dominated by amalgamated and condensed fossil-rich beds. The Virgin Limestone member was deposited during a subsequent (Spathian) Early Triassic sea level rise, about 4-5 Ma following the Permian/Triassic boundary, and includes nearshore and inner shelf limestones characterized by fossiliferous storm beds.Because the fossiliferous limestones of the Smithian Sinbad and the Spathian Virgin were deposited in similar shallow subtidal settings, they provide an opportunity to compare and contrast the status of biotic rebound at different points along an Early Triassic “time transect.” Analysis of bulk samples reveals that the older Sinbad and younger Virgin are similar in each possessing 2-3 different benthic marine paleocommunities of low within-habitat species richness. There are, however, several important differences between the Sinbad and Virgin faunas. The richly fossiliferous Sinbad assemblages are primarily molluscan, composed of approximately 2-8 species of bivalves, which may or may not be accompanied by ammonoids and 0-11 species of gastropods. Small spines, possibly belonging to an echinoid, are numerous in some samples. Although bivalves are also abundant in Virgin Limestone assemblages, fossils of other higher taxa are well-represented, including abundant crinoid ossicles, common brachiopods, echinoid spines and plates, and rare ammonoids and gastropods. Sinbad faunas also appear to lack epibionts and borers, while they are present but not abundant in the Virgin.The addition from Sinbad to Virgin times of groups other than molluscs, with different life habits and strategies, most likely led to an increase in spatial partitioning and resource utilization, in particular the development of epifaunal tiering with the appearance of stalked crinoids in the Virgin. This pattern of earliest Triassic community dominance by molluscs followed by later more “Paleozoic-like” communities has been observed in other regions. Earliest Triassic paucity of epibionts and borers indicates significant reduction in the biotic component of taphonomic processes, including taphonomic feedback, when compared with other time intervals. Data from these Early Triassic assemblages thus indicate the initiation of both an evolutionary and an ecological rebound between Sinbad (Smithian) and Virgin (Spathian) times.

Sign in / Sign up

Export Citation Format

Share Document