Effect of climate fluctuations on long-term vegetation dynamics in Carolina bay wetlands

Chrissa L. Stroh; Diane Steven; Glenn R. Guntenspergen

doi:10.1672/06-117.1

Revising key parameters for long-term carbon cycle models

10.5194/egusphere-egu21-2794 ◽

2021 ◽

Author(s):

Chloé M. Marcilly ◽

Trond H. Torsvik ◽

Mathew Domeier ◽

Dana L. Royer

Keyword(s):

Sea Level ◽

Age Distribution ◽

Silicate Weathering ◽

Geological Time ◽

Sea Levels ◽

Climate Fluctuations ◽

Climate Gradients ◽

Sea Level Fluctuations ◽

Temperature And Precipitation

CO2 is the most important greenhouse gas in the Earth&#8217;s atmosphere and has fluctuated considerably over geological time. However, proxies for past CO2 concentrations have large uncertainties and are mostly limited to Devonian and younger times. Consequently, CO2 modelling plays a key role in reconstructing past climate fluctuations. Facing the limitations with the current CO2 models, we aim to refine two important forcings for CO2 levels over the Phanerozoic, namely carbon degassing and silicate weathering.Silicate weathering and carbonate deposition is widely recognized as a primary sink of carbon on geological timescales and is largely influenced by changes in climate, which in turn is linked to changes in paleogeography. The role of paleogeography on silicate weathering fluxes has been the focus of several studies in recent years. Their aims were mostly to constrain climatic parameters such as temperature and precipitation affecting weathering rates through time. However, constraining the availability of exposed land is crucial in assessing the theoretical amount of weathering on geological time scales. Associated with changes in climatic zones, the fluctuation of sea-level is critical for defining the amount of land exposed to weathering. The current reconstructions used inmodels tend to overestimate the amount of exposed land to weathering at periods with high sea levels. Through the construction of continental flooding maps, we constrain the effective land area undergoing silicate weathering for the past 520 million years. Our maps not only reflect sea-level fluctuations but also contain climate-sensitive indicators such as coal (since the Early Devonian) and evaporites to evaluate climate gradients and potential weatherablity through time. This is particularly important after the Pangea supercontinent formed but also for some time after its break-up.Whilst silicate weathering is an important CO2 sink, volcanic carbon degassing is a major source but one of the least constrained climate forcing parameters. There is no clear consensus on the history of degassing through geological time as there are no direct proxies for reconstructing carbon degassing, but various proxy methods have been postulated. We propose new estimates of plate tectonic degassing for the Phanerozoic using both subduction flux from full-plate models and zircon age distribution from arcs (arc-activity) as proxies.The effect of revised modelling parameters for weathering and degassing was tested in the well-known long-term models GEOCARBSULF and COPSE. They revealed the high influence of degassing on CO2 levels using those models, highlighting the need for enhanced research in this direction. The use of arc-activity as a proxy for carbon degassing leads to interesting responses in the Mesozoic and brings model estimates closer to CO2 &#160;proxy values. However, from simulations using simultaneously the revised input parameters (i.e weathering and degassing) large model-proxy discrepancies remain and notably for the Triassic and Jurassic.&#160;

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Testing Farmers’ Perception of Climate Variability: A Case Study from Kirtipur of Kathmandu Valley

Hydro Nepal Journal of Water Energy and Environment ◽

10.3126/hn.v11i1.7200 ◽

2012 ◽

pp. 30-34

Author(s):

Jiban Mani Poudel

Keyword(s):

Climate Change ◽

Climate Variability ◽

Global Climate ◽

Climatic Variability ◽

Global Perspective ◽

Kathmandu Valley ◽

Climatic Fluctuations ◽

Climate Fluctuations ◽

Global And Local

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

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Development of a management tool for reservoirs in Mediterranean environments based on uncertainty analysis

Natural Hazards and Earth System Science ◽

10.5194/nhess-12-1789-2012 ◽

2012 ◽

Vol 12 (5) ◽

pp. 1789-1797 ◽

Cited By ~ 8

Author(s):

R. Gómez-Beas ◽

A. Moñino ◽

M. J. Polo

Keyword(s):

Uncertainty Analysis ◽

Water Cycle ◽

Integrated Management ◽

Management Tool ◽

Short Term ◽

Climate Fluctuations ◽

The Social ◽

Reservoir Watershed ◽

Supply Capacity

Abstract. In compliance with the development of the Water Framework Directive, there is a need for an integrated management of water resources, which involves the elaboration of reservoir management models. These models should include the operational and technical aspects which allow us to forecast an optimal management in the short term, besides the factors that may affect the volume of water stored in the medium and long term. The climate fluctuations of the water cycle that affect the reservoir watershed should be considered, as well as the social and economic aspects of the area. This paper shows the development of a management model for Rules reservoir (southern Spain), through which the water supply is regulated based on set criteria, in a sustainable way with existing commitments downstream, with the supply capacity being well established depending on demand, and the probability of failure when the operating requirements are not fulfilled. The results obtained allowed us: to find out the reservoir response at different time scales, to introduce an uncertainty analysis and to demonstrate the potential of the methodology proposed here as a tool for decision making.

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Long-period changes of the air temperature in Tatarstan and their forecast till the end of the 21st century

Journal of the Belarusian State University. Geography and Geology ◽

10.33581/2521-6740-2019-2-94-107 ◽

2019 ◽

pp. 94-107

Author(s):

Yuri P. Perevedentsev ◽

Konstantin M. Shantalinskii ◽

Boris G. Sherstukov ◽

Alexander A. Nikolaev

Keyword(s):

Surface Temperature ◽

Air Temperature ◽

21St Century ◽

Ocean Surface ◽

The Arctic ◽

Long Distance ◽

Climate Fluctuations ◽

Long Period ◽

The Earth

Long-term changes in air temperature on the territory of the Republic of Tatarstan in the 20th–21st centuries are considered. The periods of unambiguous changes in the surface air temperature are determined. It is established that the average winter temperature from the 1970s to 2017, increased in the Kazan region by more than 3 °C and the average summer temperature increased by about 2 °C over the same period. The contribution of global scale processes to the variability of the temperature of the Kazan region is shown: it was 37 % in winter, 23 % in summer. The correlation analysis of the anomalies of average annual air temperature in Kazan and the series of air temperature anomalies in each node over the continents, as well as the ocean surface temperature in each coordinate node on Earth for 1880 –2017, was performed. Long-distance communications were detected in the temperature field between Kazan and remote regions of the Earth. It is noted that long-period climate fluctuations in Kazan occur synchronously with fluctuations in the high latitudes of Asia and North America, with fluctuations in ocean surface temperature in the Arctic ocean, with fluctuations in air temperature in the Far East, and with fluctuations in ocean surface temperature in the Southern hemisphere in the Indian and Pacific oceans, as well as air temperature in southern Australia. It is suggested that there is a global mechanism that regulates long-term climate fluctuations throughout the Earth in the considered interval of 200 years of observations. According to the CMIP5 project, climatic scenarios were built for Kazan until the end of the 21st century.

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