This thesis seeks to investigate what shapes climate change policies in Kenya. Using Peter Haas' concept of usable knowledge, it argues the need to move beyond conventional perspectives on knowledge and power and provides a framework for understanding what knowledge and mechanisms are usable for policy makers. I argue that Kenyan climate policy is shaped by the interaction of knowledge and power across three crucial levels of influence - global, regional and national. As climate change forces us to rethink how we combine economic policies with environmental realities in Africa, each level encompasses distinct policy narratives where critical actors have an impact on national climate change policy. First, I argue that the standards, norms and regulations established by the global climate regime are directly reflected in national climate strategies of African countries, not only in terms of diplomatic moves to adhere to commitments made, but also in respect to benefiting from international mechanisms put in place to aid developing countries. Second, I examine the One Voice, One Africa narrative. This looks at the rise of the African Group of Negotiators within the global climate regime and their ability to influence Kenyan policy. Third, Kenya's climate change policy is shaped by the interaction of economic, political, and environmental constructs in national policy-making. The principle goal of this thesis is to open African environmental scholars and climate change policy analysts to a rigorous and flexible questioning of how climate policy processes operate in the African context.

Lightning represents a key interaction with climate through its production of nitrogen oxides (NOx) which lead to ozone production. These NOx emissions are generally calculated interactively in chemistry-climate models but there has been little development of the representation of the lightning processes since the 1990s. In most models the parametrisation of lightning is based upon simulated cloud-top height. The aims of the thesis are: to explore existing schemes, and develop a new process-based scheme, to parametrise lightning; to use a new process-based lightning scheme to give insights regarding the role of lightning NOx in tropospheric chemistry; and to use alternative lightning schemes to improve the understanding of the response of lightning to climate change, and the consequent impacts on tropospheric chemistry. First, a new lightning parametrisation is developed using reanalysis data and satellite lightning observations which is based on upward cloud ice flux. This parametrisation is more closely linked to thunderstorm charging theory. It greatly improves the simulated zonal distribution of lightning compared to the cloud-top height approach, which overestimates lightning in the tropics. The new lightning scheme is then implemented in a chemistry-climate model, the UK Chemistry and Aerosol model (UKCA). It is evaluated against ozone sonde measurements with broad global coverage and improves the simulation of the annual cycle of upper tropospheric ozone concentration, compared to ozone simulated with the cloud-top height approach. This improvement in simulated ozone is attributed to the change in ozone production associated with the improved zonal distribution of simulated lightning. Subsequently, data from a chemistry-climate model intercomparison project (ACCMIP) are used to study the state-of-the-art in lightning NOx parametrisation along with its response to climate change. It is found that the models using the cloud-top height approach produce a very similar response of lightning NOx to changes in global mean surface temperature of +0.44± 0.05 TgNK-1, for a baseline emission of 5 TgN yr-1. However, two models using two alternative lightning schemes produce a weaker and a negative response of lightning to climate change. Finally, simulations in a future climate scenario for year 2100 in the UKCA model were performed with the cloud-top height and the ice flux parametrisations. The lightning response to climate change when using the cloud-top height scheme is in good agreement with the positive response found in the multi-model results of the cloud-top height approach. However, the new ice flux approach suggests that lightning will decrease in future. These opposing responses introduce large uncertainty into the projections of tropospheric ozone and methane lifetime in the future scenario. An analysis of the radiative forcing from these two species also shows the large uncertainty in the individual methane and ozone radiative forcings in the future. Due to the opposite effect that lightning NOx has on methane (loss) and ozone (production) the net radiative forcing effect of lightning in present-day and future is found to be close to zero. However, there is a small positive feedback suggested by the results of the cloud-top height approach, whereas no feedback is evident with the ice flux approach. These results show there are large and crucial uncertainties introduced by lightning parametrisation choice, not only in terms of the actual lightning distribution but also atmospheric composition and radiative forcing. The new ice-based parametrisation developed here offers a good alternative to the widely-used approach and can be used in future to model lightning and develop the understanding of associated uncertainties.

<p> This dissertation details a doctoral research project studying three food-plants&mdash;and their potential for introduction into diet and agriculture in Northern California. Applying post-qualitative methods to multispecies ethnography, I followed three food-plants (millets, edible bulbs, and milkweeds) through their life cycles and production chains, considering their many interactions with other species and the biosphere, as well as with humans. Each food's story emerged while investigating the food-plant and its potential as an appropriate crop for Northern California's changing climate. I followed each food's lifecycle, both textually and in the field, uncovering intra-actions along a "soil to sustenance" framework. The study is presented as a narrative that examines each food within cultural and biological contexts. Expanding current crop introduction efforts within a biocultural diversity framework, I call for a diversification of our choices for crops based not only on historical and cultural relevance, but also on current and future relevance for an evolving place and time. In this way, we can look to adaptive crops and traditions from around the globe, representing both a decolonization and a diversification of agriculture and diet.</p><p>

Thesis (Ph.D.)--Boston University / PLEASE NOTE: Boston University Libraries did not receive an Authorization To Manage form for this thesis or dissertation. It is therefore not openly accessible, though it may be available by request. If you are the author or principal advisor of this work and would like to request open access for it, please contact us at open-help@bu.edu. Thank you. / Whether a species will flourish or face extinction under a new climate regime is largely determined by its dispersal ability, its adaptive capacity or some combination of these processes. These processes have also played important roles in the evolutionary histories of species, ultimately shaping their contemporary distributions. In terrestrial studies, a landscape genetics approach is often used to explain how geographic, ecological and evolutionary processes interact to structure spatial genetic variation across populations, but these approaches have only begun to be used in marine ecosystems. This dissertation fills an emerging niche in marine ecology by taking an interdisciplinary seascape genetics approach to investigating the interplay of climate, dispersal and adaptation as shallow-water marine fishes respond to environmental heterogeneity over space and climatological shifts over time. [TRUNCATED] / 2031-01-02

Climate change and extreme weather events are affecting the environment, and people’s livelihood in both developing and developed countries. Agriculture, forestry, fishing, livestock, water resources, human health, terrestrial ecosystems, biodiversity, and coastal zones are among the major sectors impacted by these shocks. The challenge of adaptation is particularly acute in the developing countries, as poverty and resource constraints limit their capacity to act. Bangladesh fits in this category, and thus I use data from Bangladesh to analyze the adaptation process in the first and second chapter of my dissertation. In the first chapter, I investigate whether transient shocks (flood, cyclone) or permanent shocks (e.g., river erosion that leads to permanent loss of lands) have more influence on interregional migration. Findings of the study suggest that the households prefer to move to the nearest city when the environmental shock is temporary, whereas they tend to relocate over a greater distance when the environmental shock is more permanent in nature. In the second chapter, I investigate the feasibility of a set of adaptation measures to cope with hydro-climatic shocks (e.g. floods, drought, cyclones, tidal waves) and epidemic shocks (emergence or re-emergence of infectious diseases on livestock and poultry) in the agricultural sector in Bangladesh. Findings suggest that a decrease in agricultural income due to climatic and/or epidemic shocks is likely to induce households to adapt more. Developed countries are also vulnerable to extreme weather events and climatic shocks. In 2017, United States was hit by three consecutive hurricanes: Harvey, Irma, and Maria. Given the rising exposure and the increasing need to manage coastal vulnerability, the third essay focusses on understanding household preferences for financing adaptation activities in the U. S. and analyzes which mechanism, i.e., state or federal adaptation fund approach, is better suited to managing exposure to such types of natural disaster in the future.

Human activities such as urban settlement, farming, forestry and recreation, have caused deterioration of water quality in many freshwater lakes worldwide. Apart from anthropogenic impacts, it is also recognized that climate has a direct influence on lake water temperature, nutrient loads, phytoplankton abundance and chemistry. However, little is known about the potential effects of future climate change on lake water quality. Understanding the dynamics, abundance and availability of nutrient pools in lake bottom sediments is fundamentally important for predicting how, and over what time-scales, lake ecosystems will respond to future scenarios such as climate change, in-lake restoration or altered external nutrient loading. Through a sediment field study on 14 different lakes, and applications of complex lake ecosystem models to three New Zealand lakes, this study examined the spatial and temporal dynamics of sediment nutrient concentrations, and made considerations of the effects of restoration measures and future climate change on lake water quality. To gain insight into processes influencing the dynamics of horizontal and vertical gradients of sediment nutrient concentrations, intact sediment cores were collected from twelve lakes within the Bay of Plenty province, North Island of New Zealand. In addition, intact sediment cores were collected from shallow Lake Te Waihora (Ellesmere) in the Canterbury province, South Island of New Zealand and shallow Lake Taihu in the Jaingsu province, China. The observed vertical concentration profiles of total phosphorus (TP) in the sediments revealed that the shape of these profiles can be similar across gradients of widely differing trophic status. Empirical and mechanistic steady state profile models were derived to describe the vertical distribution of total carbon (TC), total nitrogen (TN) and TP concentrations in the sediments. These models revealed that density-driven burial and biodiffusive mixing, which in the models also includes effects of redox-driven gradients, are strongly correlated with vertical gradients of sediment TC, TN and TP content, whereas lake trophic status was not. Despite enhancing knowledge of the processes influencing vertical gradients of sediment nutrient concentrations, little is known about the rates at which sediment nutrient concentrations may change as a response to changes in external loading or climate. Studies into the composition of bottom sediments have been undertaken intermittently over the past three decades for the 12 lakes in the Bay of Plenty. These studies, together with the data collected in this study, were used to quantify temporal changes in sediment chemistry across the lakes. Comparison of the data collected in this study with results from a survey in 1995 showed that surficial sediment (0-2 cm) TP concentrations have increased in three of the 12 lakes, at rates ranging from 27.5 to 114.4 mg P kg-1 dry wt yr-1. TN concentrations in surficial sediments have increased in nine of the 12 lakes at rates ranging from 51.8 to 869.2 mg N kg-1 dry wt yr-1. A correlation analysis revealed that temporal changes in sediment TP and TN concentrations were not significantly linearly related (pgt0.05) to catchment area or temporal changes of different water column indices considered to reflect lake trophic state, including annual mean water column concentrations of TP, TN or chlorophyll a (Chl a). While vertical profiles of sediment nutrient concentrations can be used to provide information about historical changes of trophic status in lakes, little is known about horizontal variability of sediment nutrient concentrations, including possibly relationships with horizontal variations in water column variables. In the large, shallow and eutrophic Lake Taihu, China, there are distinct horizontal water column concentration gradients of nutrients and Chl a. Concentrations are generally high in the north, where some of the major polluted tributaries enter the lake, and relatively low in the south, where macrophytes generally are abundant. To test whether these water column concentration gradients are similarly reflected in spatial heterogeneity of nutrient concentrations within the bottom sediments of Lake Taihu, I examined correlations between concentrations of TP and TN in surficial sediments (0-2 cm) and TP, TN and Chl a concentrations in water column samples determined for 32 sites in 2005. Linear correlation analysis revealed that surficial sediment TP concentrations across the 32 stations were related significantly, though weakly, to annual mean water column concentrations of TP and TN as well as Chl a. Correlations of surficial sediment TN with water column variables were, however, not significant (p gt 0.05). To better understand the effects of future climate change on lakes of different trophic status, I applied the one-dimensional lake ecosystem model, DYRESM-CAEDYM, to oligo-mesotrophic Lake Okareka, eutrophic Lake Rotoehu and highly eutrophic Lake Te Waihora. All three models were calibrated based on a three-year period (July 2002 - June 2005) and validated on a separate two-year period (July 2005 - June 2007). The model simulations generally showed good agreement with observed data for temperature, dissolved oxygen (DO), and total nutrient and Chl a concentrations. To represent a possible future climate of 2100, temperature predictions were derived from the regional climate model, DARLAM, based on the Intergovernmental Panel on Climate Change (IPCC) A2 scenario, which suggests that air temperatures by the year 2100 will increase by an average of 2.5 'C and 2.7 'C for the Bay of Plenty and the Canterbury province, respectively, relative to the base scenario (years 2002-2007). Model simulations of the future climate scenarios indicate that climatic changes generally will lead to a degradation of lake water quality in all three lakes, especially during summer months, and further suggest that the effects on annual mean surface concentrations of TP, TN and Chl a will be equivalent to an increase in external TN and TP loading by 25-50%. Simulations for Lake Rotoehu, where diatoms and cyanophytes were represented in the conceptual model, further suggest that cyanophytes will be more abundant in the future, increasing by gt15% in annual mean biomass. Although the effects of climate change may be delayed or slightly mediated by the chemical resilience of the sediment nutrient pools, the effects of climate change on lake water quality in the New Zealand lakes will be of a magnitude that should be considered as management strategies are planned and implemented, thus increasing the probability of successful preservation or improvement in water quality in future decades.

University of Technology, Sydney. Faculty of Science. / Global climate change is leading to the rise of ocean temperatures and is triggering mass coral bleaching events on reefs around the world. This involves the expulsion of the symbiotic dinoflagellate algae, known as zooxanthellae, from the coral host. Coral bleaching is believed to occur as a result of damage to the photosynthetic apparatus of these symbionts, although the specific site of initial impact is yet to be conclusively resolved. This thesis examined a number of sites within the light reactions of photosynthesis and evaluated the efficiency of photoprotective heat dissipating pathways. Upon expulsion, the capacity for long-term survivorship of expelled zooxanthellae in the water column was also assessed. A reduction in photosystem II (PSII) photochemical efficiency during exposure to elevated temperature and high light (bleaching conditions) was found to be highly dependent upon the increase in abundance of QB non-reducing PSII centres (inactive PSII centres), indicating damage to the site of the secondary electron acceptor, QB, resulting in a limited capacity for its reduction. Therefore, this reduced the rate of the reoxidation of the primary electron acceptor, QA-. Fast induction curve (FIC) analysis of the rise from minimum fluorescence to maximum fluorescence revealed a lower amplitude in the J step along this curve, which was consistent with a reduction in the rate of QA reoxidation. This photoinhibition of PSII was found to occur once the effectiveness of excess energy dissipation through energy-dependent quenching and state-transition quenching was exceeded, suggesting that these mechanisms were incapable of preventing photodamage. Antenna size heterogeneity showed little change under bleaching conditions with a significant increase in PSIIbeta only apparent in one species of coral. The thermostability of the oxygen evolving complex (OEC) and thylakoid membrane were found to increase during exposure to bleaching conditions and exceeded bleaching thresholds of corals. This rapid rise in temperature-dependent thermostability also occurred over seasons, where variation in ocean temperatures was matched by gradual shifts in OEC and thylakoid membrane thermotolerance. Variation in thermostability between species was not found to be linked to zooxanthellae genotype, and instead was related to the bleaching susceptibility of the host. Despite this capacity for resilience to bleaching conditions, the PSII reaction centres did not exhibit such a mechanism for rapid acclimatisation. Corals can only be as tolerant to bleaching conditions as their most sensitive component allows. The formation of nonfunctional PSII centres is therefore suggested to be involved in the initial photochemical damage to zooxanthellae which leads to a bleaching response. Zooxanthellae were found to be expelled irrespective of OEC function and thylakoid membrane integrity, as these sites of the photosynthetic apparatus were still intact when cells were collected from the water column. Although zooxanthellae were photosynthetically competent and morphologically intact upon expulsion, their longevity in the water column was dependent on the time of expulsion following the onset of bleaching and the ambient water temperatures. The survivorship of these zooxanthellae was restricted to a maximum of 5 days in the water column which suggests that unless expelled zooxanthellae inhabit other environs of coral reefs which may be more favourable for survival, their capacity for persistence in the environment is extremely limited. Chlorophyll a fluorescence measurements are a common tool for investigating photosynthetic impacts to in hospite zooxanthellae of corals. Pathways causing dark-reduction of the plastoquinone pool are shown to be active in corals and affect measurements which require dark-adaptation. Pre-exposure to far-red light was found to be an effective procedure to oxidise the inter-system electron transport chain and ensure determination of the true maximum quantum yield of PSII and accurate FICs. It is concluded that the trigger for coral bleaching lies in the photosynthetic apparatus of zooxanthellae and evidence is presented in support of this impact site not being the OEC or thylakoid membrane.

<p>The Arctic region attracts considerable scientific interest in these years. Some of the Earth's most pronounced signs of the recent climate change are found here. The summer sea-ice cover is shrinking at an alarming rate. At the same time the region warms faster than the rest of the globe.</p><p>The sea-ice reduction implies an increase of solar-radiation absorption at the surface leading to warming which is expected to be larger at higher than at lower latitudes. It is therefore often assumed that the sea-ice reduction is a major cause of the observed Arctic temperature amplification. However, results presented in this thesis suggest that the snow and ice-albedo feedbacks are a contributing but not dominating mechanism behind the Arctic amplification. A coupled climate-model experiment with a doubling of the atmospheric CO2 concentration reveals a considerable Arctic surface-air-temperature amplification in a world without surface-albedo feedback. The amplification is only 8 % larger when this feedback is included. Instead the greenhouse effect associated with an increase of humidity and cloud cover over the Arctic seems to play a major role for the amplification.</p><p>Reanalysis data, which are partly based on observations, show Arctic temperature amplification well above the surface in the troposphere. In the summer season, the amplification has its maximum at ~ 2 km height. These trends cannot be explained by the snow- and ice-albedo feedbacks which are expected to induce the largest amplification near the surface. Instead, a considerable part of the trends aloft can be linked to an increase of the atmospheric energy transport into the Arctic.</p><p>A major topic of this thesis is the linkage between the mid-latitude circulation and the Arctic warming. It is suggested that the atmospheric meridional energy transport is an efficient indicator of this linkage.</p>

<p>This is a thesis regarding a local event that occurred in Babati district in North-Eastern Tanzania during the autumn of 2009. In the district the period between June-November is normally a dry period, but this year the serenity of the drought was considered as harsher than usual. The majority of the workforce in Tanzania and in Babati is within the agricultural sector, and thus are directly dependant on the weather for the cultivation of the crops. A severe drought that wipes out the larger amount of the yield is devastating for the farmer-households, both socially and economical. The drought in question may or may not have been a result of climate changes, but it can be used as a mirror to future and present events that actually happens due to a changed climate. The reactions and consequences that this drought had on the people who got affected can tell us something about how future changes of the climate, or even temporary fluctuations of the weather, may concern people globally.</p><p>My field study confirms the gendered imbalance in resilience against ecological changes, by illuminating how the women-headed households were the group that had been hardest hit of the farmers that I interviewed. This can be connected to a pandemic structure where poor, rural women constitute the most vulnerable group when it comes to ecological catastrophes and changed patterns in weathers and/or climate. The social impacts that the drought had on the inhabitants of Babati in general, and it’s female inhabitants maintaining on agricultural in particular, works as a general example on how people that already constitute a marginalized group in society, are the least resilient when it comes to endure natural catastrophes.</p><p> </p><p> </p><p><em> </em></p>

<p>The urgency of climate change is pressing on the development of different technologies to reduce greenhouse gas emissions among which carbon dioxide (CO2) is the most abundant. A great source of CO2 is the burning of fossil fuels. The installation of carbon capture and storage (CCS) technology could reduce the amount of CO2 released from larger combustion processes by up to 90%. Fossil fuels stand for a great part of the total consumption of energy in the society today. To replace it so rapidly that strict climate change objectives will be reached with only increased energy efficiency and renewable energy would be difficult and would not be the most cost-efficient strategy. To be able to stabilize the atmospheric CO2 level within this decade and in a cost-efficient manner, the development of CCS technologies is clearly needed as a complementary strategy.</p>