The total mangrove area cover in South Africa is 1631.7 ha, with the largest area cover in a few estuaries in the KwaZulu-Natal Province (1391.1 ha) and the remainder recorded in the Eastern Cape Province with 240.6 ha. This represents 0.05 percent of Africa‟s mangrove area cover and although small adds irreplaceable value to the biodiversity of South Africa. Mangroves are threatened by over-utilization through harvesting for firewood and building materials as well as excessive browsing and trampling by livestock. The objective of this study was to investigate the response of mangroves to different stressors from natural change as well as anthropogenic pressures. This was done by identifying pressures, measuring area cover, population structure and environmental parameters such as sediment characteristics. Mangroves in 17 estuaries along the east coast were investigated. Population structure and the area covered by mangroves in 2011/2012 were compared with data from the same area for 1999. Detailed studies were conducted in St. Lucia Estuary to investigate the response of mangroves to reduced tidal flooding; mangrove expansion at a latitudinal limit in a protected area at Nahoon Estuary was studied and the effect of cattle browsing on mangroves was measured at Nxaxo Estuary. The St. Lucia Estuary (28°S; 32°E) represented a unique study site as the mouth has been closed to the sea since 2002 and the mangrove habitats have been non-tidal. St. Lucia Estuary is both a Ramsar and World Heritage site and therefore understanding the response of mangroves to changes in the environment is important. In 2010 sediment characteristics and mangrove population structure were measured at four sites which were chosen to represent different salinity and water level conditions. The site fringing the main channel had the highest density of mangrove seedlings and saplings. The dry site had a lower density of mangroves with mostly only tall adult trees and few saplings. Mangrove tree height and density increased at sites with high sediment moisture and low surface sediment salinity. Few seedlings and saplings were found at sites with dry surface sediment and high salinity. Long term data are needed to assess the influence of mouth closure on recruitment and survival of the mangrove forest at St. Lucia Estuary; however this study has shown that sediment characteristics are unfavourable for mangrove growth at sites now characterized by a lack of tidal flooding. It is not known when exactly the mangroves were planted in Nahoon Estuary (32°S; 27° E), East London, but it is suspected that this was in the early 1970s. Avicennia marina (Forrsk.)Vierh. was planted first, followed a few years later by the planting of Bruguiera gymnorrhiza (L.) Lam. and Rhizophora mucronata (L.) among the larger A. marina trees. Surprisingly the mangrove population appears to be thriving and this study tested the hypothesis that mangroves have expanded and replaced salt marsh over a 33 year period. This study provides important information on mangroves growing at higher latitudes, where they were thought to not occur naturally due to lower annual average temperatures. It further provides insights on future scenarios of possible shifts in vegetation types due to climate change at one of the most southerly distribution sites worldwide. The expansion of mangroves was measured over a 33 year period (1978 - 2011) using past aerial photographs and Esri ArcGIS Desktop 10 software. In addition, field surveys were completed in 2011 to determine the population structure of the present mangrove forest and relate this to environmental conditions. The study showed that mangrove area cover increased linearly at a rate of 0.06 ha-1 expanding over a bare mudflat area, while the salt marsh area cover also increased (0.09 ha-1) but was found to be variable over time. The mangrove area is still small (< 2 ha) and at present no competition between mangroves and salt marsh can be deduced. Instead the area has the ability to maintain high biodiversity and biomass. Avicennia marina was the dominant mangrove species and had high recruitment (seedling density was 33 822 ± 16 364 ha-1) but only a few Bruguiera gymnorrhiza and Rhizophora mucronata individuals were found (< 10 adult trees). The site provides opportunities for studies on mangrove / salt marsh interactions in response to a changing climate at the most southern limit of mangrove distribution in Africa. This research has provided the baseline data, permanent quadrats and tagged trees to be used in future long-term monitoring of population growth and sediment characteristics. At Nxaxo Estuary (32°S; 28°E) the response of mangrove trees (Avicennia marina) to cattle browsing and trampling was investigated by using cattle exclusion plots. Exclusion plots were established by fencing in five 25 m2 quadrats and adjacent to each experimental quadrat a control quadrat (not fenced in, 25 m2) was set-up. Trees were tagged and measured annually from 2010 to 2012. Sediment salinity, pH, moisture, organic content, compaction as well as sediment particle size was also measured in each quadrat. Sediment characteristics did not vary between control and experimental plots but did show changes between the years. The mangrove trees in the cattle exclusion plots grew exponentially over a period of two years. There was a significant increase in mean plant height (5.41 ± 0.53 cm), crown volume (0.54 ± 0.01 m3) and crown diameter (7.09 ± 0.60 cm) from 2010 to 2012. Trees in the control plots had significantly lower growth (p < 0.05). There was a decrease in plant height (-0.07 ± 0.67cm1) and only small increases in crown volume (0.14 ± 0.1 m3) and crown diameter (2.03 ± 2.61 cm). The research showed that browsing on mangroves by cattle stunts growth and causes a shrubby appearance as a result of coppicing. The browsed trees were dwarfed with horizontal spreading of branches and intact foliage close to the ground while the plants in the cattle exclusion plots showed an increase in vertical growth and expansion. In the cattle exclusion plots there was a significantly higher percentage of flowering (67 percent) and fruiting (39 percent) trees in 2012 compared to the control sites where 34 percent of the plants were flowering and 5.4 percent of the plants carried immature propagules. Observations in the field also indicated that cattle had trampled a number of seedlings thus influencing mangrove survival. The study concluded that browsing changes the morphological structure of mangrove trees and reduces growth and seedling establishment. This is an additional stress that the mangroves are exposed to in rural areas where cattle are allowed to roam free. Seventeen permanently open estuaries provide habitat for mangrove forests along the former Transkei coast. This part of the Eastern Cape is mostly undeveloped and difficult to access. Mangrove area cover, species distribution, population structure and health of the mangrove habitat were compared with results from previous studies in 1982 and 1999. The mangrove Bruguiera gymnorrhiza had the densest stands and was widely distributed as it was present in 13 of the 17 estuaries. Avicennia marina was dominant in those estuaries which had the largest area cover of mangroves and was present in 10 estuaries, while Rhizophora mucronata was rare and only present in five estuaries. Anthropogenic and natural impacts were noted within the mangrove habitats in each of these estuaries. Harvesting of mangrove wood, livestock browsing and trampling and footpaths occurred in most of the estuaries (> 70 percent). It was observed that browsing on trees resulted in a clear browse-line and browsing on propagules mainly by goats resulted in reduced seedling establishment in most of the estuaries except those in protected areas. Mangroves had re-established in estuaries where they had been previously lost but mouth closure due to drought and sea storms resulted in the mass die back of mangroves in the Kobonqaba Estuary. There was a total loss of 31.5 ha in mangrove area cover in the last 30 years and this was a total reduction of 10.5 ha (11 percent) for every decade. This is high considering that the present total mangrove area cover is only 240.6 ha for all the Transkei estuaries. In this study it was concluded that the anthropogenic impacts such as livestock browsing and trampling as well as harvesting in these estuaries contributed most to the mangrove degradation as these are continuous pressures occurring over long periods and are expected to increase in future with increasing human population. Natural changes such as sea storms occur less frequently but could result in large scale destruction over shorter periods. Examples of these are mouth closure that result in mangrove mass mortality as well as strong floods which destroy forest by scouring of the banks.

Streamflow records in many regions of Eurasia including South Asia are short and fragmentary. This makes it challenging to contextualise natural climate variability relative to anthropogenic climate change and evaluate the severity of recent extreme events. In the first section of the dissertation (Chapter 1 and 2) we use tree rings to reconstruct centennial-scale streamflow of the Indus and Brahmaputra Rivers in South Asia for the past six centuries. These two rivers and their tributaries are fed by Himalayan glaciers and the South Asian Monsoon and are the basis of economic, social, and cultural life of over 700 million people in the region. These centennial reconstructions of past discharge provide valuable information about long-term hydroclimate variability, drought and flood hazard. They also help us to interpret recent climate extremes relative to those in the past and benchmark projections of climate change for the region. Large tropical (and extratropical) volcanic eruptions can release large quantities of reflective sulphate aerosols into the stratosphere where they may persist for up to 3 years. In Chapter 3 we discuss how these aerosols can impact European and Mediterranean hydroclimate by causing dry conditions over northwestern Europe and the British Isles and wet conditions over the western Mediterranean. We examine this hydroclimate response using Superposed Epoch Analysis (SEA), a statistical method used to identify consistent responses to events by testing for the possibility of random occurrence. Finally, in Chapter 4 we describe in further detail (cf. Chapter 3) the modified double-bootstrap SEA that we developed in Chapter 3 to examine the uncertainty inherent in SEA within a probabilistic framework. We describe our modified SEA by applying it to two datasets, a reconstruction of northern hemisphere summer temperature for the past millennium, and a compilation of tree ring fire scar records for the western U.S. Using these two datasets we examine post-eruption northern hemisphere cooling following volcanism and the synchrony between drought conditions and fire events in the western U.S. respectively.

Extant literature has struggled to identify definitive purpose for shareholder proposals, finding them to depend on their context. Progressively, climate change has gathered interest at annual meetings where shareholders present proposals related to the subject. The literature builds expectations for the role of obsolescence, regulation and other forms of activism to motivate innovation with respect to these proposals. The literature also establishes how diversification can serve as a defense. I test the impact that shareholder proposals have on the information environment and on the corporate behaviors of innovation and diversification. I find that capital markets are responsive to proposal pressures and that there are improvements in the information environment. I find that firms in receipt of shareholder proposals related to climate change innovate and diversify more. I find wealth enhancements for these corporate behaviors spurred by climate-related proposals. While definitive statements on causality may elude, my results suggest that shareholder proposals have real effects. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2020. / FAU Electronic Theses and Dissertations Collection

The measurements from Microwave Sounding Unit (MSU) and Advanced Microwave Sounding Unit-A (AMSU-A) have been extensively used for atmospheric temperature trend study during last several decades. The existences of inter-sensor biases and orbital drift, orbital differences among different satellites are two major challenges for climate study using long-term time series of satellite measurements. In this study, the impacts of orbital drift and orbital differences of satellites on AMSU-A derived temperature trends over Amazon rainforest are investigated. The AMSU-A near-nadir observations from NOAA-15, NOAA-18, NOAA-19, and MetOp-A during 1998 - 2014 are employed. The double difference method is firstly applied to obtain the estimates of inter-sensor biases for each paired AMSU-A instruments, in which NOAA-18 is used as a reference satellite. The inter-calibrated observations from the four satellites mentioned above are used to calculate monthly mean diurnal cycles of brightness temperature for each of the 15 AMSU-A channels. The diurnal correction method is then applied to all AMSU-A data using the estimated diurnal-cycle variations in order to obtain corrected data valid at the same local time. Finally, it is shown that the inter-sensor bias correction and diurnal correction have significant impacts on the AMSU-A derived long-term atmospheric temperature trends. / A Thesis submitted to the Department of Earth, Oceanic and Atmospheric Sciences in partial fulfillment of the requirements for the degree of Master of Science. / Spring Semester, 2015. / February 26, 2015. / Advanced Microwave Sounding Unit-A, climate trend, diurnal correction, inter-sensor bias correction, orbital differences, orbital drift / Includes bibliographical references. / Ming Cai, Professor Directing Thesis; Peter S. Ray, Committee Member; Zhaohua Wu, Committee Member.

The purpose of this dissertation is to examine how horizontal and vertical governance structure affects energy and sustainability policymaking at the local level. Although sustainability is an important issue at all levels of government in the American federal system, local governments increasingly play a major role in the development and implementation of policies directed at enhancing environmental outcomes such as energy conservation. Accordingly, sustainability research is beginning to shift more of its attention to municipalities, developing a framework for understanding global climate change as a local issue, and examining the influence and corresponding effects local institutions have in the implementation of sustainability policies. However, previous studies tend to overlook the importance and impact of intergovernmental relations on urban sustainability outcomes. The dissertation particularly analyzes how the relations between local and higher-level governments influence local institutional structures in addressing energy conservation and climate change concerns, as well as "green" energy policy outcomes at the local level. This research advances our theoretical understanding of interlocal collaboration and the impact of federal grant programs on local implementation efforts. This dissertation contains three essays. The first essay examines how state laws and institutions influence interlocal collaboration. The second essay analyzes how federal rules and regulations affect local governmental decisions to engage in collective action. Finally, the third essay determines the direct impact of a federal grant program on local green policy outcomes. / A Dissertation submitted to Reubin O'D. Askew School of Public Administration and Policy in partial fulfillment of the requirements for the degree of Doctor of Philosophy. / Fall Semester, 2014. / November 4, 2014. / Climate change protection policy, Energy Efficiency and Conservation Block Grant, Federalism, Intergovernmental Relations, Interlocal Collaboration / Includes bibliographical references. / Richard C. Feiock, Professor Directing Dissertation; Tingting Zhao, University Representative; Kaifeng Yang, Committee Member; Keon-Hyung Lee, Committee Member.

Global Climate Models (GCMs) and Regional Climate Models (RCMs) represent the atmospheric processes that are nonlinear by nature and are therefore sensitive to small perturbations. The RCMs are provided time dependent Lateral Boundary Conditions (LBCs) either from the GCM or the reanalyses and hence the RCMs are not expected to deviate much from the forcing fields as expected for a free non-linear system. If a GCM is used in a nested system, the nested solutions will be subject to the internal variability of both the GCM and the RCM. The study aims to investigate the variability caused by the internal variability of the GCM and the RCM. The study then looks into the contribution of the RCM’s internal variability to the total variability of the different nested system solutions. In this study four solutions obtained through perturbing the wind fields at initialisation for the ECHAM4.5 are used to force an RCM, the RegCM3, over South Africa. The solutions that are obtained are functions of the internal variability of the ECHAM4.5 as well as of the RegCM3. To determine the amount of the variability that is introduced by the RCM’s internal variability, four other RegCM3 simulations are made through initialising the RegCM3 on different days but using a single realisation from the GCM. The rainfall variability associated with the combined internal variability of both the models is high to an extent that ensemble members produce anomalies that have opposite signs in the same season. However, the sign of the ensemble average anomaly generally corresponds with the observed anomaly. The variability associated with the internal variability of the RCM is negligible when seasonal totals are analysed while with the daily rainfall totals the variability is larger. The variability in areas where small amounts of rainfall occur is smaller than that of the high rainfall regions. The number of events that fall into the three rainfall categories (i.e. below-normal, normal and above-normal) for the RegCM3 ensemble members are close to one another however the timing of the events is different. The results suggest that in operational forecasting making ensemble members associated with the internal variability of an RCM is not necessary because the information obtained from the ensemble members is almost similar. / Dissertation (MSc)--University of Pretoria, 2006. / Geography, Geoinformatics and Meteorology / MSc / Unrestricted

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A dissertation submitted to the Faculty of Science in fulfilment of the requirements for the degree Master of Science, University of the Witwatersrand, Johannesburg, 2019 / Tropical cyclones are becoming more intense and the locations at which they form and attain their lifetime maximum intensities are migrating poleward, exposing more regions to tropical cyclone impacts. This study investigated a new climatology for Southern Hemisphere tropical cyclones, aimed to update and re-examine the previous tropical cyclone climatology from the canonical works of Gray (1968, 1979). The optimal and minimum ranges of thermodynamic and dynamic climate variables during tropical cyclogenesis were determined, to define the conditions at which the majority of Southern Hemisphere tropical cyclones are generated. The change over time of tropical cyclone activity and the magnitude of the climate drivers at the 1000and 850mb levels was also examined. The sea surface temperatures of 27.5-28.5°C is observed as the optimal range at which a majority of storms undergo genesis. However, the lowest observed magnitude at which genesis was possible is 24°C. This challenges the 26.5°C threshold for genesis in the Southern Hemisphere. Based on factor analysis weightings and multivariate regression, sea surface temperature, air temperature and relative humidity also account for a relatively large amount of variability in the formation process of tropical cyclones, compared to the other climate variables examined. Over 1980-2016, an increase for Southern Hemisphere tropical cyclone maximum intensity of 2.4 m.s-1 per decade is observed. Of the climate drivers measured at the point of genesis; omega, meridional shear, sea surface temperature and solar flux display statistically significant correlations with tropical cyclone intensity. Sea surface temperature, air temperature, solar flux and vertical shear at the point of genesis for Southern Hemisphere tropical cyclones, demonstrate statistically significant increases in magnitude, while omega and relative humidity indicate a decreasing trend. The increase in thermodynamic variables and their relationship to storm intensity infers that a warming climate is capable of influencing tropical cyclone intensity. The El Niño Southern Oscillation, Indian Ocean Dipole, Southern Annular Mode and volcanic eruption events indicated a statistically significant relationship to metrics of tropical cyclone activity, mainly intensity and longitude of storm genesis. The tropical cyclone climatology established here by providing an up to date seasonality and background of Southern Hemisphere tropical cyclone activity, can assist impact and risk assessment studies in areas potentially vulnerable to tropical cyclone impacts within the Southern Hemisphere. / TL (2020)

The purpose of this exploratory collective case study is to understand how climate change education can meet the learning needs of emergency management professionals to prepare and adapt to the impacts of climate change on communities throughout the United States. The primary research question guiding the study was: How do emergency managers experience, learn about, and from, the impacts of climate change in their work? Throughout the study, significant attention was paid to emergent themes in emergency managers’ personal and professional learning and development in the form of multiple data collection methods and analysis. The following sub-questions were also investigated:A. How do perceptions of climate change influence the ways in which emergency managers engage with climate literacy? B. What do emergency managers perceive as important for the content and design of climate literacy training and education programs to support their learning? This collective case study involved the participation of six (N = 6) certified emergency management (CEM) professionals currently practicing in the U.S. as the study’s key informants (KIs). The sequential data collection methods encompassed a survey, semi-structured interviews, and the utilization of the Sustainability Mindset Indicator (SMI) assessment. Additionally, the survey administered to the six KIs was also distributed to a larger sample (N = 56), known as a “boosted sample,” to compare and contrast wider trends, transferability and uncover broader training needs. Data analysis leveraged coding to identify similarities and differences among emergency managers’ lived experiences, approaches, and expert recommendations on learning about climate change-related themes. The theoretical framework that guided this research analysis was the Sustainability Mindset Principles (SMPs). This study aimed to inform future training and education programs for emergency managers on climate change as well as provide researchers and practitioners working in climate science with insights on how to engage emergency management. The study found that emergency managers in the U.S. are increasingly recognizing the multifaceted impacts of climate change on their roles and responsibilities. Emergency managers reported a preference for localized climate information that extends beyond geography to encompass cognitive, social, political, and historical dimensions. Participants reported a preference for climate-related training to be presented in practical ways with an emphasis on increasing long-term thinking skills in their training. The study observed that emergency managers exhibited strong motivation, preparation for future learning, and sense of purpose that can be applied to integrating climate change information into existing emergency management frameworks. Emergency managers acknowledged the need to refine roles and collaborate across sectors to effectively address climate change given resource limitations, including funding, workforce development, and technology. Building upon a robust training infrastructure in emergency management, climate literacy can facilitate an understanding of climate within the field as well as the widespread effects that transcend a single profession, sector and generation.

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