Life-climate interactions on the Archean Earth and exoplanets

Finding life beyond the Earth remains one of the major drivers of science today. The search for extra-solar life has predominantly been based on Earth-like biosignatures from across Earth's history, such as oxygen and methane. Life on Earth has changed dramatically since the origin of life, with life on the early Earth potentially an important period to understand when looking for life on other planets. In this thesis, I investigate the interaction between life and the environment, with a general focus on life before the advent of oxygenic photosynthesis. Methane is thought to have been an important greenhouse gas during the Archean, although its potential warming has been found to be limited at high concentrations due to its high shortwave absorption. I used the Met Office Unified Model (UM), a general circulation model, to further explore the climatic effect of different Archean methane concentrations. Surface warming peaks at a pressure ratio pCH₄:pCO₂ of approximately 0.1, reaching a maximum of up to 7 K before significant cooling above this ratio. Equator-to-pole temperature differences also tend to increase up to pCH₄≤300 Pa, which is driven by a difference in radiative forcing at the equator and poles by methane and a reduction in the latitudinal extend of the Hadley circulation. 3D models are important to fully capture the cooling effect of methane, due to these impacts of the circulation. I then shift the focus to exoplanets. The majority of detected potentially habitable exoplanets orbit stars cooler than the Sun and are therefore irradiated by a stellar spectrum that peaks at longer wavelengths than the spectrum incident on Earth. I present results from a set of simulations of tidally locked terrestrial planets orbiting three different host stars to isolate the effect of the stellar spectra on the simulated climate. Specifically, we perform simulations based on TRAPPIST-1e, adopting an Earth-like atmosphere and using the UM. Whilst holding the planetary parameters constant, including the total stellar flux (900 W/m²) and orbital period (6.10 Earth days), we compare results between simulations where the stellar spectrum is that of a quiescent TRAPPIST-1, Proxima Centauri, and the Sun. In simulations with cooler host stars, an increased proportion of incident stellar radiation was absorbed directly by the troposphere compared to the surface. This in turn led to an increase in the stability against convection, that is, a reduction in overall cloud coverage on the dayside (reducing scattering), leading to warmer surface temperatures. The increased direct heating of the troposphere also led to more efficient heat transport from the dayside to the nightside and therefore to a reduced day-night temperature contrast. We inferred that planets with an Earth-like atmosphere orbiting cooler stars had lower dayside cloud coverage, potentially allowing habitable conditions at increased orbital radii, compared to similar planets orbiting hotter stars for a given planetary rotation rate. Finally, after improving our understanding of the Archean and Earth-like planets orbiting M-dwarf planets, I focus on the interaction between the biosphere and the atmosphere for Earth and how this may differ on a planet orbiting an M-dwarf, TRAPPIST-1e, and the possible effect this may have on the detection of life on such a planet. I develop and apply a coupled 1D atmosphere-ocean-ecosystem model to understand how primitive biospheres that exploit free-energy gradients between possible abiotic sources of H₂, CO and O₂ could influence the atmospheric composition of rocky terrestrial exoplanets. I apply this to the Earth at 3.8 Ga and to TRAPPIST-1e. I focus on metabolisms that evolved before the evolution of oxygenic photosynthesis, which consume H₂ and CO and produce potentially detectable levels of CH₄. Oxygen-consuming metabolisms are also considered for TRAPPIST-1e as abiotic oxygen production is predicted. I show that these primitive biospheres can lead to high levels of abiotic oxygen (close to 10 %), which is a result of converting an H₂ flux into a biotic CH₄ flux which could stabilise high oxygen scenarios. The inclusion of oxygen-consuming metabolisms could lower oxygen levels to around 10 parts per million and support a productive biosphere at low reductant inputs. I find that CO metabolism is as productive as H₂ metabolisms for a planet orbiting an M-dwarf. Using predicted transmission spectral features from CH₄, CO, O₂/O₃ and CO₂ across the hypothesis space for tectonic reductant input, I show that biotically produced CH₄ may only be detectable at high reductant inputs. CO is also likely to be a dominant feature in transmission spectra for planets orbiting M-dwarfs, which could reduce the confidence in any potential biosignature observations linked to this species. Finally, this thesis covers future work, and some proof of concept experiments that advance the discussed work further.Hill Family Scholarshi

Providing Feedback Following Leadership Walkrounds is Associated with Better Patient Safety Culture, Higher Employee Engagement and Lower Burnout

Background There is a poorly understood relationship between Leadership WalkRounds (WR) and domains such as safety culture, employee engagement, burnout and work-life balance. Methods This cross-sectional survey study evaluated associations between receiving feedback about actions taken as a result of WR and healthcare worker assessments of patient safety culture, employee engagement, burnout and work-life balance, across 829 work settings. Results 16 797 of 23 853 administered surveys were returned (70.4%). 5497 (32.7% of total) reported that they had participated in WR, and 4074 (24.3%) reported that they participated in WR with feedback. Work settings reporting more WR with feedback had substantially higher safety culture domain scores (first vs fourth quartile Cohen’s d range: 0.34–0.84; % increase range: 15–27) and significantly higher engagement scores for four of its six domains (first vs fourth quartile Cohen’s d range: 0.02–0.76; % increase range: 0.48–0.70). Conclusion This WR study of patient safety and organisational outcomes tested relationships with a comprehensive set of safety culture and engagement metrics in the largest sample of hospitals and respondents to date. Beyond measuring simply whether WRs occur, we examine WR with feedback, as WR being done well. We suggest that when WRs are conducted, acted on, and the results are fed back to those involved, the work setting is a better place to deliver and receive care as assessed across a broad range of metrics, including teamwork, safety, leadership, growth opportunities, participation in decision-making and the emotional exhaustion component of burnout. Whether WR with feedback is a manifestation of better norms, or a cause of these norms, is unknown, but the link is demonstrably potent

A DYNAMIC ANALYSIS OF HUMAN WELFARE IN A WARMING PLANET”

Climate stabilization requires low GHG emissions. Is this consistent with nondecreasing human welfare? Our welfare index, called quality of life (QuoL), emphasizes education, knowledge, and the environment. We calibrate a multigenerational model with education, physical capital, knowledge and the environment. We reject discounted utilitarianism and adopt, first, the Intergenerational Maximin criterion, and, second, Human Development Optimization, that maximizes the QuoL of the first generation subject to a given future rate of growth. The computed paths have a QuoL higher than the year 2000 level for all generations. They require doubling the labor resources devoted to the creation of knowledge, whereas the fractions of labor allocated to consumption and leisure are similar to the reference ones. Higher growth rates require substantial increases in the fraction of labor devoted to education, together with moderate increases in the fractions of labor devoted to knowledge and the investment in physical capital.Quality of life, climate change, education, maximin, growth

A Review of Recent Studies on Cost Effectiveness of GHG Mitigation Measures in the European Agro-Forestry Sector

Over the last twenty years, climate change has become an increasing concern for scientists, public opinions and policy makers. Due to the pervasive nature of its impacts for many important aspects of human life, climate change is likely to influence and be influenced by the most diverse policy or management choices. This is particularly true for those interventions affecting agriculture and forestry: they are strongly dependent on climate phenomena, but also contribute to climate evolution being sources of and sinks for greenhouse gases. This paper offers a survey of the existing literature assessing cost, effectiveness and efficiency of greenhouse gas mitigation strategies, or broader economic reforms, targeted to the agricultural and forestry sectors. The specific focus is on European Countries. Different methodological approaches, research questions addressed and results are examined. The main finding is that agriculture and forestry can potentially provide GHG reduction at a competitive cost. Nevertheless this cost is positive; accordingly, mitigation policies should be carefully designed either to balance costs with expected benefits or to avoid excessive penalisation of the sectors involved. Finally needs are highlighted for improving the existing knowledge and research methodologies.Agriculture, Forestry, Climate Change, Greenhouse Gases, Policy Measures, Cost-Effectiveness, Meacap

Enhancing Food Security in a Changing Climate in Africa

Climate and socio-ecological change scenarios are invaluable tools in developing appropriate response options for ensuring food security and human wellbeing in the future: evidence-based approach. Climate change necessitates research on crops, livestock and systems that are resilient to variability and extreme events. Prioritize and mainstream food security and nutrition issues into regional and national climate change adaptation and mitigation programmes and initiatives. Opportunities exist for the development of climate-proof and resilient food systems across Africa through technology diffusion, agronomic practices and innovations that can be optimized and scaled up

Climate change and health in Earth's future

Threats to health from climate change are increasingly recognized, yet little research into the effects upon health systems is published. However, additional demands on health systems are increasingly documented. Pathways include direct weather impacts, such as amplified heat stress, and altered ecological relationships, including alterations to the distribution and activity of pathogens and vectors. The greatest driver of demand on future health systems from climate change may be the alterations to socioeconomic systems; however, these “tertiary effects” have received less attention in the health literature. Increasing demands on health systems from climate change will impede health system capacity. Changing weather patterns and sea-level rise will reduce food production in many developing countries, thus fostering undernutrition and concomitant disease susceptibility. Associated poverty will impede people’s ability to access and support health systems. Climate change will increase migration, potentially exposing migrants to endemic diseases for which they have limited resistance, transporting diseases and fostering conditions conducive to disease transmission. Specific predictions of timing and locations of migration remain elusive, hampering planning and misaligning needs and infrastructure. Food shortages, migration, falling economic activity, and failing government legitimacy following climate change are also “risk multipliers” for conflict. Injuries to combatants, undernutrition, and increased infectious disease will result. Modern conflict often sees health personnel and infrastructure deliberately targeted and disease surveillance and eradication programs obstructed. Climate change will substantially impede economic growth, reducing health system funding and limiting health system adaptation. Modern medical care may be snatched away from millions who recently obtained it

Faculty Agency: Departmental contexts that matter in faculty careers

The purpose of this study was to investigate the organizational factors that influence faculty sense of agency in their professional lives and whether the relationship between organizational factors and faculty agency manifests differently by gender. Past literature on faculty has largely taken an approach that was termed a "narrative of constraint," focusing on the challenges that faculty face in modern academe, such as increased academic capitalism, striving, and new technologies (O'Meara, Terosky, & Neumann, 2008; Schuster & Finkelstein, 2006). More recently, certain scholars sought to understand what keeps faculty satisfied and thriving in a higher education context with multiple challenges (Baez, 2000a; Neumann, Terosky, & Schell, 2006; O'Meara, Terosky, & Neumann, 2008). The construct of agency is a powerful perspective to uncover how faculty navigate academe and succeed in their own goals. Guided by the O'Meara, Campbell, and Terosky (2011) framework on agency in faculty professional lives, this study used Structural Equation Modeling to investigate which organizational factors (perceptions of tenure and promotion process, work-life climate, transparency, person-department fit, professional development resources, and collegiality) influenced faculty agency perspective and agency behavior and whether agency was associated with important faculty outcomes, such as intent to stay, satisfaction, and productivity. Then, this studied investigated whether the resulting model differed by gender. Results showed that work-life climate and person-department fit had a positive direct influence on agency perspective and a positive indirect influence on agency behavior. Professional development resources had a positive influence on agency perspective, but a negligible influence on agency behavior. Results also showed a very large effect of agency perspective on agency behavior. The invariance test by gender demonstrated that the relationships between organizational factors and faculty sense of agency were the same for men and women. This study illustrated the importance of departmental contexts in faculty professional lives, regardless of gender. It has important implications for administrators regarding departmental role in faculty agency, and also contributes to the continued development of a theoretical framework on faculty agency

Biomass and Carbon Uptake of Mangrove Forests Pohorua Village, Muna Regency

Environmental conditions caused by air pollution are so large that it impacts on changes in the ecosystem that affects all aspects of human life. Climate change is caused by increasing greenhouse gases in the earth's atmosphere because the Earth's atmosphere receives more carbon than it releases. This study aims to determine the potential of biomass and carbon uptake in mangrove stems in Pohorua village, Muna Regency. The research is quantitative descriptive, sampling using the Point Center Quarted Method (PCQM) technique measured around the height of the chest height mangrove tree (DBH). Data analysis was performed using an allometric equation in which each mangrove plant has a specific gravity. Carbon uptake found in mangroves stored in the roots, stems and leaves of mangrove plants, the results of the study showed that mangroves can absorb carbon quickly