Earth Sciences Commons^™

Climate Change: Adapting Tropical And Subtropical Grasslands, G M. Mckeon, S M. Howden, N.O J. Abel, J M. King

IGC Proceedings (1977-2023)

Climate change as a result of increasing greenhouse gas concentrations or lhe repetition of historical climale variability will affect the management and production of tropical and subtropical grasslands that support about half the world's domestic herbivores. Previous studies of the regional impact of climate change and climate variability on intensive agriculture have shown lhat such evaluation should include the known and expected abilities of managers and governments to respond by reducing the negative impacts and taking advantage of positive opportunities, A high priority for grassland scientists is the development of similar evaluation capabilities for grassland systems, which are more complex …

Evaluating The Effects Of Climate Changes On Grasslands, Robert G. Woodmansee, William E. Riebsame

IGC Proceedings (1977-2023)

Determining the effects of climate change on cold region grasslands requires the integration of knowledge from the biological, physical and social sciences. That integration is dependent on new methods, technologies and facilitation techniques ! that allow evaluation and management of complexity rather than focusing on simplification. Specifically, grassland response can be defined as the interaction of 10 basic sectors: (I) wenther and climate (Including chemical factors}, (2) winter, (3) soil properties, (4) assemblages of organisms, (5) energy, (6) economic viability, (7) individual human behavior, (8) cultural and community viability, (9) organisational penalty, and (10) political, legal, policy, and regulatory Influences. …

Prediction Of Grassland Plant Responses To Global Change, B D. Campbell, J P. Grime

IGC Proceedings (1977-2023)

Global change is challenging the predictive power of biology. Increasingly, biologists are being asked to draw together existing knowledge and new experimental data, in order to provide predictions of the effects of global change at regional, national and global scales. In this paper we examine how well global change effects on grassland plants can be predicted, and what avenues might be used in future to improve predictive capabilities. Broad predictions of the direction of change in grassland vegetation can be made quite simply and from a limited set of data. Predictions of the rate and magnitude of change are more …

Variation In The Response Of Pasture Plants To Carbon Dioxide, B D. Campbell, W A. Laing, P.C D. Newton

IGC Proceedings (1977-2023)

The percentage increases in growth resulting from a doubling of atmospheric CO2 concentration were measured for 37 common pasture plants under strictly controlled conditions of temperature, nutrient supply and irradiance. A wide range of variation in potential response lo CO2 was detected in the day/night temperature range 12n°c to 28/ 23°C. C4 species responded litlle to elevated CO2 The mean ± standard deviation of the distribution of c3 species responses ranged from l±21% at 1m•c to 90±40% at 28/23°C. These responses varied with the stage of plant development. The response by Lolium perenne cv. Grasslands Nui was of intermediate size …

Will Subtropical Grasses Keep Spreading Through New Zealand?, B D. Campbell, R.J M. Hay

IGC Proceedings (1977-2023)

n this paper we briefly examine the effects that rising temperature and atmospheric CO2 concentrations may have on the spread of subtropical grasses in New Zealand. Data are presented from controlled-environment experiments measuring the growth and competitive suppression of white clover by a variety of local temperate and subtropical grasses at CO2 concentrations of 3S0 ppm and 700 ppm. These data support the prediction that some subtropical grasses may decline in aggressiveness relative to temperate species in New Zealand in the future as atmospheric CO2 levels rise. Some of the factors likely to modify the expression of temperature and CO2 …

Effect Of Carbon Dioxide Concentration On The Competitive Ability Of Clover: Measurements Of Growth And Rubisco, W A. Laing, D H. Greer, B D. Campbell

IGC Proceedings (1977-2023)

White clover (Trifolium repens cv. Grasslands Huia) was grown in competition with one of 10 established grass species or else grown alone. Plants were grown at either 350 or 700 ppm CO2, at 28/23°C and 700 µmol/m1/sec photon flux density. Plant growth and extractable ribulose bisphosphate carboxylase (rubisCO) were measured. Grass growth responded less to CO2 than clover. In the absence of grass competition, clover growth Increased 30% under 700 ppm CO2 compared with 350 ppm, but the response varied from 0% to 100% • when grass competition was present. Increased CO2 reduced extractable rubisCO activity (expressed on a …

Response Of Natural Turves Of Pasture To Elevated Carbon Dioxide In A Controlled Environment, P.C D. Newton, H Clark, C C. Bell, E M. Glasgow

IGC Proceedings (1977-2023)

Large natural turves from a ryegrass-white clover (Lolium pernne, trifolium repens) pasture were exposed to increasing day/nighl temperatures at 350 and 700 µVI CO2 over a 7•month period. Growth rate al the highest temperature (22/16°C day/night) was IS% higher at the elevated CO2 level; at lower temperatures the response to CO2 was reduced or even negative (-6% at 10/4°C). The growth rate of ryegrass was much lower at elevated CO2 while that of white clover and other grasses was increased. These results are compared with previous studies using synthetic communities, and the limited response to CO2 is noted …

Effect Of Elevated Carbon Dioxide On The Performance Of Nine Coexisting Grassland Species, J Watson, J D. Graves

IGC Proceedings (1977-2023)

Microcosms were constructed to represent a neutral grassland community under traditional agricultural management. During a season of fumigation at ambient and 600 µmot/mot CO2, plant performance was recorded. An increase of biomass for the whole community resulted at elevated CO2, but the response of individual species differed, There are indications that competitive interactions may change within a community due to the effects of CO2 enrichment; this may eventually result in a change in species composition.

Comparison Of Photosynthetic Responses To Carbon Dioxide In Pasture Species, D H. Greer, W A. Laing, B D. Campbell

IGC Proceedings (1977-2023)

Thirteen major pasture species were grown in controlled environments at 3 temperatures (12n, 18/13 and 28/23°C) and at 350 nnd 700 ppm CO2 for 4-8 weeks and net photosynthesis measured under these conditions. In C1 cultivars, short-term (within minutes) exposure to elevated CO2 had the greatest effect on photosynthesis, with an average of 55% higher rates than that at ambient CO2. There was also a response to long-term growth at high CO2, with a,1 average of 40% higher rates of photosynthesis than at ambient CO2 (both measured al their growth CO2) and a marked alteration in the temperature dependence Qf …

Modeling The Effects Of Climate Variability And Climate Change On A Pastoral Farming System, R J. Martin, D B. Baird, M J. Salinger, P R. Van Gardingen, D G. Mccall

IGC Proceedings (1977-2023)

A simulation model was used to investigate the pasture and animal production and gross margins of a typical all sheep permanent pasture farm in South Canterbury, New Zealand, using 60 years of current climate data, and also a climate change scenario. The model was run on a fixed management system at different stocking rates with and without destocking during feed shortages. Mean annual pasture production was 8060 kg/ha, with a coefficient of variation of 22%. Destocking enabled more stock to be carried on average, with higher, but rh.ore variable, returns. A climate change scenario of a 75% increase in CO2' …

Changes To Sheep Grazing Systems In Response To Climate Change, B M. Butler, S T. Morris, R S. Morris

IGC Proceedings (1977-2023)

Simulation models were used to predict changes in pasture growth and sheep farming systems as a result of changes in climate due to global warming. The results of long•lerm mean climate and 10 years' individual climate simulations show Iha! increases in stocking rate of up to 40% may be possible with climate change. Benefits of climate change included increased lamb carcass weight and pasture cover. Climate change also resulted in the feasibility of autumn lambing systems in an environment in which these systems are currently difficult lo maintain. A change from 100% spring lambing to 40% of the flock lambing …

Climate Change And Variability: Impacts On New Zealand Pastures, M J. Salinger, A S. Porteous

IGC Proceedings (1977-2023)

Climate change and variability influence the productivity and distribution of New Zealand pasture species. Temperature and rainfall scenarios are used to explore the sensitivity of New Zealand pastures to potential climate warming next century. Temperature affects the length of the growing season with present pasture species extending 200 m higher in altitude for every 1 •c temperature increase. The greater area of New Zealand that becomes frost free allows the spread of subtropical pasture grasses southwards. However, where low rainfall limits pasture production, changes to the rainfall amount have a significant effect. A rainfall change of I 0% changes the …

A Climate Change Perspective On Grasslands, A Barrie Pottock

IGC Proceedings (1977-2023)

Grasslands are the result of interactions between climate, soil, interspecies competition and natural or humnn distucbance. They are vital to human sustenance but vulnerable to human mismanagement and climatic stress.• Thece is now a strong scientific consensus that climate will change during the next century at a rate unprecedented since the end of the last glaciation. Expected climatic changes include not only increasing temperatures, but also changes in total rainfall and its seasonality, and systematic increases in rainfall intensity. Along with the direct effects of increasing carbon dioxide concentrations on plants, and changes in fire frequency, these environmental influences will …

Supplementary Files For "Impact Of Snow Accumulation On Structural Integrity: Present And Future Perspectives", Kenneth Pomeyie, Brennan Bean

Browse all Datasets

Evaluating the impact of weight exerted by settled snow (i.e., snow load) on structures poses numerous statistical challenges, including missing data, biased distribution parameters, and the influence of climate change. This dissertation aims to address challenges related to the use both direct and indirect measurements of snow load (or equivalently, snow water equivalent), as well as the anticipated impact of climate change on future extreme snow loads. The first paper within this dissertation investigates short-term snow loads by comparing various techniques for estimating extreme values of short-term snow accumulations. Additionally, the first paper includes a comparative analysis of short-term and …

Coastal Flood Risk In The Context Of Climate Change And Urbanization In Northeastern South Carolina, Hongyuan Zhang

Electronic Theses and Dissertations

Researchers and the public now widely recognize the seriousness of coastal flood risks. Various changes in natural processes, such as altered rainfall patterns, increased tropical cyclone intensities, and sea-level rise, are consequences of global warming induced by heightened greenhouse gas concentrations. To comprehensively understand coastal compound flooding, it is crucial to consider multiple processes and their interactions. Moreover, the growth of coastal cities and the concentration of people and assets in these areas make them increasingly vulnerable to flooding events. Accurately estimating the future flood risks faced by coastal communities necessitates addressing the compounding effects on coastal flood risk, taking …

Simulation Models As Decision Aids For Management Of Rangeland Ecosystems, J Ross Wight, Clayton L. Hanson

IGC Proceedings (1977-2023)

Rangeland simulation models have been used primarily as research tools to synthesise and organise information and to conceptualise and describe the interacting components of the ecosystem. Their application as decision aids for range management has not been developed. This paper discusses ways simulation models, such as SPUR· (Simulation of Production and Utilisation of Rangelands), can be used to forecast herbage p1oduction and the occurrence of biological windows, enhance monitoring, and predict the impacts of management and climate change on the soil, water, and plant resources including species composition.

Comprehensive Climate Vulnerability Assessment Of A Regional Karst Landscape For Hazard Mitigation Planning, Kara Brunot

Masters Theses & Specialist Projects

Climate change is the global phenomena affecting all sectors of society by creating conditions more conducive for the occurrence of extreme weather events. It is projected that the intensity and frequency of events will increase. Flooding, in particular, is projected to increase in frequency due to more intense precipitation events. Karst landscapes are especially vulnerable to climate change impacts because of their unique hydrology and geology. Karst flooding is most likely to occur from prolonged or intense rain events, which climate change will likely make more feasible. Areas are disproportionately affected by climate change due to population demographics and environmental …

A Seasonal Decomposition Comparison Between Forest And Turf Habitats: Implications For Climate Change, Amanda Shirmer

DePaul Discoveries

Decomposition is an essential ecosystem service in which microorganisms breakdown organic matter. This process improves soil health and acts as a vital step in global carbon cycles. In this study, we examined decomposition rates and associated soil properties in turf and forest habitats across summer and fall seasons in order to determine how land management practices and climate change may be altering local decomposition regimes. Our study determined that there was a statistically significant difference between decomposition rates in turf and forest ecosystems (P=0.003) and a significant difference in decomposition rate across season (P

Socio-Economic And Climate Change In Mongolia - Effects On Grassland Ecosystems, C Opp

IGC Proceedings (1977-2023)

In Mongolia, in combination with strong changes of the whole society during the past 76 years, from the feudal system to socialism and from the socialist system of planned development to the market economy, there are a lot of changes in the use of natural resources all over the country. In consequence of this a lot of effects on grassland ecosystems, caused by socio-economic and climate driving factors, were observed and studied in different scales: zonal, regional, local.

Long-Term Effects Of Co2 Enrichment And Temperate Increase On Forage Quality In A Temperate Grass, J F. Soussana, J M. Besle, I Chabaux, P Loiseau, P C. De Faccio Carvalho

IGC Proceedings (1977-2023)

Perennial ryegrass swards were grown during two years at two N fertilizer supplies in elevated (700 ppm) or ambient atmospheric CO2 concentration at outdoor temperature and at + 3°C in elevated CO2. Elevated CO2 and temperature increase had only minor impacts on the digestibility and on the fiber composition of the cut material. On average, the water soluble carbohydrate concentration of the leaf laminae was doubled in elevated CO2, whereas a 3°C temperature increase reduced this concentration by 25 %.

Co2 Enrichment And Temperature Effects On Productivity Of Field-Grown Phalaris And Subterranean Clover, J M. Lilley, T P. Bolger, R M. Gifford

IGC Proceedings (1977-2023)

Pure and mixed swards of Phalaris aquatica and Trifolium subterraneum were exposed to cool (ambient) and warm (cool +3oC) temperatures, at both 380 and 690 ppm CO2 concentrations in field temperature gradient tunnels for 5 months. In general, clover and the mixture had similar forage productivity in each treatment, while phalaris was less productive. Elevated CO2 increased clover production 40% in the monoculture and the mixture. Higher temperatures reduced clover regrowth at ambient CO2 and reduced the response to elevated CO2 in the monoculture but not in the mixture. In contrast, phalaris regrowth in the monoculture was not increased by …

Effects Of Climate Change On Grassland Production In Switzerland, J Fuhrer, M Riedo

IGC Proceedings (1977-2023)

A mechanistic model for productive grassland was used to simulate annual dry matter yield in relation to fluxes of C, N, and water, and to test the sensitivity to climate change and to elevated [CO2] (2xCO2). Local weather scenarios were derived from the results of two General Circulation Models (GCM) by statistical down-scaling. Annual yield increased by a maximum of 10% without 2xCO2 effects, by 1-16% in response to 2xCO2, and by 6-24% with the combination of climate change and 2xCO2. Decreased evapotranspiration and increased water use efficiency in response to 2xCO2 were partially offset by climate change. The simulations …

The Influence Of Sediment-Supply On River Recovery From Reach To Watershed-Scales, Jordan Fields

Dartmouth College Ph.D Dissertations

Alluvial channels are always amidst cycles of disturbance and response, continually arcing towards, or back to, a dynamic equilibrium where the channel is subtly adjusted so that it is just able to transport the sediment load supplied from reaches above. As the landscape, and now the climate, have been altered by human activity, channels have been subjected to a changing balance of external forcings. Increasingly large and frequent floods, dam construction/removal, land use change, artisanal gold and sand mining all have drastically perturbed river channels’ delicate adjustment – how will they respond? Here, I consider the question from the grain …

Sub-Stage Climatic Shifts During Mis 11 Refined From Diatom Assemblage Reconstruction In The Valles Caldera, New Mexico, Savannah Cutler

Earth and Planetary Sciences ETDs

Diatom assemblage reconstruction from the Valles Caldera sediment core (VC-3) was utilized to infer climatic and aquatic changes during a 50-thousand-year [ka] period in the Mid-Pleistocene (435-385 ka). This 50 ka interval spans most of Marine Isotope Stage 11 (MIS 11) – one of the most prominent interglacials of the past 500 ka – and is widely considered an analog for the Holocene and future climate regimes. Nearly all records from MIS 11 are either marine or ice-core based, making VC-3 unique among lacustrine sediment records as it captures insolation variations and climatic changes during the mid-Pleistocene. Analysis of the …

Climate Change In Mississippi: A Journalistic Exploration Of Education And Activism, Kala Nance

Honors Theses

Climate Change in Mississippi: A Journalistic Exploration of Education and Activism takes an investigative, journalistic approach toward climate change in Mississippi. Specifically, how education and awareness have a direct impact on Mississippi industries, people and legislation. The project explored the level of acknowledgement of climate change across the state, and how certain individuals used advocacy to encourage education about climate change to raise awareness of the severity of the situation. This project includes interviews with university professors and researchers, non-profit organizations, educational groups and working individuals in some of Mississippi’s largest areas of employment. Additionally, this project draws on research …

Determining The Climatic Effects Of The Central Atlantic Magmatic Province Across The End Triassic Mass Extinction In The Elliot Formation, Southern Africa, Danielle Elizabeth Oberg

Graduate Theses and Dissertations

Understanding the intricate relation between carbon-cycle perturbations, climate change, and biodiversity stability is crucial in the face of ongoing anthropogenic greenhouse-gas emissions. This thesis explores the impacts of rapid climate change induced by carbon-cycle perturbations and their potential repercussions on global climate. Large igneous provinces, particularly the Central Atlantic Magmatic Province, offer a lens through which to examine the nexus of volcanic activity, mass extinctions, and climate change. The emplacement of Central Atlantic Magmatic Province, covering vast regions across continents, emitted substantial amounts of carbon dioxide, profoundly impacting global climate and ecosystems. The end-Triassic Mass Extinction, attributed to Central Atlantic …

Climatology Of Tornadoes In Kansas, John P. Wasinger, Todd Moore

SACAD: Scholarly Activities

Recent studies report changes to the climatology of tornadoes in the United States (US). Changes with the most supporting evidence include an increase in the intra- and inter-annual variability, increased concentration of tornadoes in bigger outbreaks, and a geographic shift of the densest tornado activity away from Tornado Alley in the Great Plains and toward the Great Lakes and Southeast regions of the US. Broad, national-level changes are valuable, but they can mask changes occurring at the state and sub-state levels where mitigation efforts are most effective. Kansas is of interest due to its reputation as a hotbed of tornado …

Hydroclimatic Trends And Streamflow Response To Recent Climate Change: An Application Of Discrete Wavelet Transform And Hydrological Modeling In The Passaic River Basin, New Jersey, Usa, Felix Oteng Mensah, Clement Aga Alo, Duke Ophori

Department of Earth and Environmental Studies Faculty Scholarship and Creative Works

The exigency of the current climate crisis demands a more comprehensive approach to addressing location-specific climate impacts. In the Passaic River Basin (PRB), two bodies of research—hydroclimatic trend detection and hydrological modeling—have been conducted with the aim of revealing the basin’s hydroclimate patterns as well as the hydrologic response to recent climate change. In a rather novel application of the wavelet transform tool, we sidelined the frequently used Mann–Kendal (MK) trend test, to identify the hidden monotonic trends in the inherently noisy hydroclimatic data. By this approach, the use of MK trend test directly on the raw data, whose results …

Automated Glacier Classification In High Mountain Asia Using Machine Learning And A Random Forest Classifier, Victoria Elizabeth Halvorson

Dartmouth College Master’s Theses

High Mountain Asia (HMA) is home to the largest mass of glaciers and ice outside the north and south polar regions. HMA glaciers are projected to experience accelerated mass loss from higher greenhouse gas emissions through the end of the century. Many studies of glacier mass balance and mass loss in HMA obtain glacier area from the Randolph Glacier Inventory (RGI). However, the RGI is designed to show glacier area across the world that is accurate to the year 2000 and, as a result, is not an accurate representation of the current state of glacier area in HMA. Additionally, glacier …

Impact Of Climate Change On Carbon And Nitrogen Balance In Zostera Marina L. (Eelgrass), Malee Jinuntuya

OES Theses and Dissertations

Seagrasses face vulnerability to both global stressors like Ocean Acidification (OA) and climate warming compounded by local stressors such as eutrophication that reduces light availability, leading to a complex dynamic of positive and negative effect on their growth and survival. Increased dissolved aqueous CO₂ (CO_2(aq)) benefits seagrasses by enhancing photosynthetic and growth rates, but it may increase nutrient demand, potentially depleting nutrient supply, especially in oligotrophic environments.

In this study, the long-term impact of CO₂ on Zostera marina L. (eelgrass) were investigated across a gradient of CO_2(aq) concentrations (55 – 2200 µM CO_{2(aq)) …}