Below are abstracts of the presentations given by the current Earth Institute Postdoctoral Research Fellows at their Fall 2010 Symposium
Our recent work showed that the public severely underestimates energy consumption and savings (Attari et al., 2010) because energy may be relatively invisible to the naked eye and is constantly transformed. Furthermore, individuals in the United States believe the most important problem facing America today is the economy, however the most important problem facing the world in the future is climate change. Thus connecting these projects, we want to investigate how creating a virtual world that allows us to speed up time and allows individuals to viscerally experience the impacts of climate change will impact attitudes, beliefs, behaviors and social norms.
Climate information may help smallholder farmers in Southeast Asia take informed risks and reduce their climate vulnerability. Model-based seasonal forecasts are limited in the skill they offer with longer lead times, and in their accessibility to farmers in remote regions. Climate reconstructions derived from tree rings can complement model-based forecasts, providing probabilistic estimates of future climate at an annual resolution. This study demonstrates the potential skill of climate reconstructions derived from tree rings to improve inter-annual decisions on Southeast Asian farms, and highlights the social research necessary to transmute this potential into a valuable climate decision aid.
An understanding of the relative impacts of the changes in climate variables on grain yield in the last decades can help develop effective adaptation strategies to cope with climate change. This study was conducted to investigate the effects of the interannual variability and trends in temperature, solar radiation and precipitation during 1961–2003 on wheat and maize yields in the double cropping system at two sites in the North China Plain (NCP), and to examine the relative contributions of the three climate variables in isolation. 129 climate scenarios consisting of all the combinations of these climate variables were designed. An ensemble of crop model driven by these climate scenarios allows assessing the impact of each single climate variable isolated from the other two.
The results showed that year-to-year variations in temperature, solar radiation and precipitation individually resulted in substantial annual differences in crop yield, especially for precipitation. The warming trend alone decreased wheat potential yield at both sites, but not significantly, due to the combined effects of temperature increase during the stages before dormancy (positive effect) and after dormancy (negative effect). Maize potential yield was significantly decreased by 2.7% yr-1 at the northern site, due to increased temperature during the growing season. The decreasing trend in solar radiation showed the strongest isolated impact on simulated yields. Its decrease caused significant reduction in potential yields at Beijing, at the rate of 5.2% yr-1 for wheat and 4.8% yr-1 for maize. Although the decreasing trends in rainfed yield of both wheat and maize were large, the large year-to-year variability of precipitation made the trends less prominent.
Over the last several decades, agricultural soils in many parts of sub-Saharan Africa have become depleted of nitrogen (N) and other nutrients, creating challenges to achieving food security in many countries. At only 8 kg N/ha/yr, average fertilizer application rates in the region are an order of magnitude lower than typical rates in the United States, and well below optimal levels. Increased use of nutrient inputs is a centerpiece of most African Green Revolution strategies, making it important to quantify the impacts of this change in practices. Increased N inputs are invariably accompanied by losses of N to the atmosphere as nitrogen oxides, including the greenhouse gas nitrous oxide (N2O).
Several investigations of greenhouse gas emissions from sub-Saharan agricultural systems have been conducted over the last 20 years, but they typically include only two levels of fertilizer additions, and so are unable to identify potentially important thresholds in the response of trace gas emissions to fertilization rate. Here I examine the response function of N2O emissions to 5 different levels of inorganic fertilizer additions in a maize field in Maseno, Kenya during the 2010 long rainy season, which starts in March. I used a randomized complete block design incorporating 5 levels of inorganic fertilizer additions (0, 50, 75, 100, and 200 kg/ha). I measured trace gas fluxes daily for one week starting the day before fertilizer application, followed by weekly measurements until trace gas emissions subsided to control levels.
Preliminary data suggest that N2O emissions may be slow to increase in response to fertilizer applications in Maseno, and are subject to important threshold effects. Overall rates of N2O emissions were a fraction of maize production systems in the United States, and did not increase as fertilizer additions increased from 0 to 100 kg/ha. Emissions doubled at 200 kg/ha, indicating the presence of a threshold between 100 and 200 kg/ha, well above the recommended fertilizer addition rates of 70-80 kg/ha. Though limited to measurements in one season, one soil type, and one location, the threshold response suggests that N2O emissions may not increase in similar soils until fertilizer additions are higher than recommended rates.
This proposed study would focus on the global production and trade of vegetable oils (e.g. palm oil, soybean oil etc); how the export and import of these commodities has changed over the last decade as well as their influence on land use change. The study would entail a combination of trade/economic analysis and targeted remote sensing across the major exporting countries; focusing on the expansion of cultivated area resulting from national and international trade policies. This study would build off of previous and ongoing efforts to model direct and indirect land use change, while considering the role of multi-lateral and bilateral trade agreements (e.g. import tariff regimes). Vegetable oils were chosen as a useful commodity to analyze, as oils from different feedstocks are generally completely substitutable, are a significant source of calories for the world’s population, and have more recently been touted as a possible input for biofuel production. In addition, cultivation of vegetable oil feedstocks is considered a significant driver of tropical land use change (e.g. soy in Brazil and oil palm in Southeast Asia). The major sources of vegetable oil are North and South America (dominated by Argentina, Brazil, Canada and the United States), South East Asia (Indonesia and Malaysia) and the European Union: while the major consumers of vegetable oil are India, China, the EU and North America (USDA/FAS 2009). Therefore, this study will analyze trade and/or cultivation data for the US, Canada, EU, Brazil, Argentina, India, China, Malaysia and Indonesia.
Crop-driven land use change has been and continues to be monitored and modeled around the world (Chowdhury 2006, Morton et al. 2006, Galford et al. 2008, Searchinger et al. 2008, GOFC-GOLD 2009, Morel unpublished); however, few studies appear to link changes in cultivated areas between temperate and tropical countries or include consideration of trade policies. Therefore, to augment the trade analysis described above, large-scale land use changes will be estimated using 250-meter MODIS imagery and nationally reported changes in a cultivated area. This analysis could be performed annually; however, realistically, may be more useful every 5 years (or following significant shifts in policies or prices).
Worldwide, 1.4 billion people lack access to electricity. To provide the services provided by electricity, people pay far higher rates for inferior ways of delivering services. The SharedSolar project endeavors to deliver electricity so that lighting and battery charging services can be purchased at lower rates than are currently being paid.
This project employs two strategies, mobile phone enabled prepayment and panel sharing. Mobile phone enabled prepayment allows customers to pay for electricity in small quantities on demand. Panel sharing allows for more efficient utilization of the available energy resource by averaging use. Additionally, automated data collection from energy sources allows for the system to be monitored remotely, lowering maintenance costs. We hope to learn what effect available electricity has on quality of life and a means of providing it in a sustainable way.
Water is necessary for life: it is needed for drinking water, agriculture, and industry. It is therefore necessary to ensure adequate, sustainable supplies of water for a region to continue to develop. Adequate water resources are therefore a determined by climate and anthropogenic use. Climate determines the quantity of water available naturally; humans modify the water cycle in many ways, such as through storage in dams, water withdrawals for agriculture and industry, and increased evapotranspiration over irrigated lands. This is particularly true in India, where precipitation is largely confined to the monsoon season, irrigated agriculture is ubiquitous, and groundwater tables are declining. This talk presents the approach I will take during my fellowship by building a large-scale water resource model which will allow for assessment of how India, as well as other regions, can provide for both water and food security in ways that are sustainable in the long-term.
Below are abstracts of the presentations given by the current Earth Institute Postdoctoral Research Fellows at their Fall 2009 Symposium: "Meeting the Challenges of Sustainability in a Changing World"
Abstract:
The recent outbreak of H1N1 is the latest example to join the list of emerging infectious diseases, including SARS, Nipah virus, and AIDS, which have capitalized on growing ties between humans and livestock and humans encroachment into wildlife habitats. Among the pathogens that have recently "spilled over" into human populations, the majority are zoonotic in nature. My research asks the question of how the fragmentation of landscapes contributes to disease emergence. As conservation efforts aim to bridge wild and grazing areas and as the intensification of livestock farming is projected to increase throughout the developing world, how will the disease landscape be transformed? I aim to capture these dynamics using spatial analysis and epidemiological modeling at the global and local levels.
Abstract:
In the tropics, high rates of deforestation and forest degradation continue to result in a loss of intact, old growth forests. At the same time, although to a much lesser extent, secondary forests are increasing in area in many parts of the tropics as forests regenerate following human land use & subsequent abandonment. Recent debate has centered on the value of these regenerating secondary forests for biodiversity conservation and ecosystem functions. Key to this debate is the resiliency of tropical forests in the face of human disturbance. In other words, will the species composition of secondary forests eventually converge on that of old growth forests, or will regenerating forests be fundamentally different from the mature forests that were present prior to human disturbance? Recent studies have suggested that, under certain conditions, tropical forests appear to be highly resilient, with old growth species successfully regenerating in the secondary forests that grew up following human disturbance. However, these studies have been conducted in areas where the natural disturbance regime is relatively benign. It is unknown whether forests show the same resiliency in the face of both human and large-scale, severe natural disturbance events, such as fires, landslides, and hurricanes.
Along with collaborators at Columbia University and the University of Puerto Rico, I have been looking at interactions between human and natural disturbance in a hurricane-impacted forest in northeastern Puerto Rico that was subject to a variety of human land uses in the first half of the 20th century (e.g. selective logging, heavy logging and small-scale agriculture). Our results suggest that, similar to previous studies, old growth species are able to regenerate in areas of secondary forest. However, we also found that hurricane disturbance fosters the regeneration of secondary forest species in old growth forest areas. These results suggest that, rather than secondary forests returning to the species composition of old growth forests, in landscapes subject to both human and severe natural disturbance, forests will increasing become a mix of both old growth and secondary forest species. A landscape-level shift in species composition would likely have significant implications for biodiversity conservation and ecosystem services.
Abstract:
Loss of natural ecosystems and the increase of annual cropping systems are inextricably linked to ecosystem function and food security. Understanding how land-use change contributes to functional soil properties such as soil organic matter cycling will help in the design of agricultural systems in order to enhance the soil ecosystem. Three Millennium Village (MV) sites (Sauri, Kenya; Ruhiira, Uganda; and Mbola, Tanzania) were chosen to develop soil organic carbon reference values at a landscape scale. Mbola site was further selected to construct a chronosequence to calculate organic matter turnover rates on two different soil types prevalent across the landscape. These three sites represent distinct forest types and are at various stages along the restoration-degradation pathway. The Land Degradation Surveillance Framework (LDSF) developed by Markus Walsh and Tor Vagen was used to sample the landscape and is a stratified random sampling design that uses a nested spatial hierarchy. Soil organic carbon (SOC) and stable carbon isotopes were measured on 171 composite soil samples from 0-20 cm and 20-50 cm depths. Paired sampling of forested and cultivated sites at the Mbola village was conducted and soil pits were excavated to classify and describe soil. Multilevel models were used to analyse variance within the hierarchy and to model parameters at different spatial scales. SOC, sand content, carbon isotope signatures varied between the three sites. SOC reference values and SOM turnover rates will be calculated and presented.
Abstract:
Solutions for two of the greatest issues of sustainability of this century, hunger and climate change could be directly at odds. Without increased productivity on existing farmland, deforestation will likely be required to meet food demands, thus increasing the release of climate forcing carbon dioxide (CO2) into the atmosphere. However improving productivity through the applications of nitrogen will likely increase the release of nitrous oxide N2O, a greenhouse gas 310 times as powerful as CO2. The net climate impact of two important sources of nitrogen, inorganic fertilizers and biological nitrogen fixation are not well understood particularly in Sub-Saharan Africa, where yield increases are needed most. The Millennium Villages Project provides an important opportunity to examine the potential tradeoffs between food production and climate mitigation where deforestation and land degradation overlap with hunger and poverty. Using two Millennium Village sites as case studies three agriculture intensification scenarios are explored for supplying nitrogen to increase crop production (inorganic fertilizer, herbaceous leguminous cover crops- green manures, and agroforestry – leguminous improved tree fallows) compared to baseline situations in terms of food security, land requirements to meet basic caloric requirements, and greenhouse gas emissions.
Abstract:
Sub-Saharan Africa has exhibited a declining trend in per capita food production since 1961; over 180 million Africans currently lack access to adequate food resources, twice as many as in 1970. Climate impacts on sub-Saharan agriculture are expected to further diminish yields by as much as 30% by 2080, increasing the number of people at risk of hunger by another third. However, these model predictions don't consider the impact that the range of interventions implemented as part of development programs such as the Millennium Village Project can have on food production. Here I show some preliminary exercises with the DSSAT crop modeling system demonstrating the potential improvements in maize production that can result from increased fertilizer additions and improved crop varieties, and show that these improvements may more than offset declines in productivity resulting from a 4 degree Celsius temperature
increase.
Abstract:
A detailed understanding of how changes in climate would impact the processes governing crop production and water balance, and which agricultural management practices should be adopted under the variable and changing climate can provide useful insights for the development of sustainable agricultural systems. We present in this work a comprehensive analysis of the similarities and differences of the impacts of climate variability/change on crop production and field water balance, and corresponding adaptation strategies for agricultural production and water resource use in China, North America and south eastern South America using an agricultural system model combined with climate models.
Abstract:
Conflict is said to rupture a society's social fabric. This has widespread implications since social cohesion is considered a foundation for sustainable political and economic development. This presentation explains a novel research design to examine if and how a development intervention - the Millennium Village Project - can help build social cohesion in post-war Liberia.
Abstract:
Stergios studies a class of differential games of pollution control with profit functions that are polynomial in the global pollution stock. Given an open-loop emissions path satisfying mild regularity conditions, a simple polynomial ambient transfer scheme is exhibited that induces it in Markov-perfect equilibrium (MPE). Proposed transfers are a polynomial function of the difference between actual and desired pollution levels; moreover, they are designed so that in MPE no tax or subsidy is ever levied. Their applicability under stochastic pollution dynamics is studied for a symmetric game of polluting oligopolists with linear demand. I discuss a quadratic scheme that induces agents to adopt Markovian emissions strategies that are stationary and linear-decreasing in total pollution. Total expected ambient transfers are always nonpositive and increase linearly in volatility and the absolute value of the slope of the inverse demand function. However, if the regulator is interested in inducing a constant emissions strategy then, in expectation, transfers vanish.
Abstract:
My research examines landscape transformations, climate-related hazards, and governance in the coastal municipalities of Santa Catarina and São Paulo, Brazil. It conceptualizes city-regions as complex social-ecological systems and considers the institutional arrangements that span public, private, and civic spheres of research, policy, and action. Brazil’s coastal cities vary in size, configuration, historical origin, and economic activity. Since the 1980s tourism has become an increasingly important component of the economic development of many of these coastal cities. More recently, developers have promoted further urban expansion in coastal Brazil by targeting affluent amenity migrants with the livability brand. The lure of livability and economic opportunities has attracted migrants of diverse socioeconomic circumstances. Domestic and international tourism and migration flows have transformed previously existing communities and ecosystems. Heterogeneous land-use patterns and disparities in building design and construction reflect this socioeconomic complexity. Densely populated coastal landscapes are exposed to multiple climate-related risks including hurricanes, cyclones, heavy rainfall, flooding, and landslides. Faced with managing growing cities in the contexts of global environmental change and economic globalization, governments are challenged to provide adequate infrastructure and services to meet housing, transportation, drainage, sanitation, water supply, and energy supply needs. These interrelated planning and development challenges present opportunities to enhance the adaptive capacity of city-regions and to design effective climate adaptation strategies.
Abstract:
This study aims to examine the motivational reasons for defection (non-cooperation) in social dilemma situations. Social dilemmas occur when individual rationality leads to collective irrationality and everyone is worse off (Kollock, 1998), such as the tragedy of the commons (Hardin 1968). There are a variety of reasons why an individual would choose to defect in social dilemmas, such as wanting to free ride on sacrifices of others, not wanting to be a sucker, not wanting to be a drop in the bucket etc. In this study, I aim to identify the most important motivations for defection to then identify ways to encourage cooperation. I also aim to address whether motivations for defection are situation dependent or whether they are based on individual differences (i.e., a certain type of person may have the same motivation for defecting in any given situation).
Abstract:
My current study explores how the people in the Azores maintain their cultural pride as Homens dos Baleeiros ("People of the Whales") in the face of climate change, altered whale behaviors, and new human relationships with the sea. Historically, the sperm whales were the main providers for human life in the Azores, and many ceremonies and social events revolved around traditional whaling. For Azorean islanders, whales not only provided sustenance but also nourished human emotions, expressive culture, and helped them cultivate their sense of place. Although traditional Azoreanwhale relationships have changed dramatically in the 1980s from subsistence and commercial whaling to whale tourism, the bond between humans and whales remain strong. However, climate change is bringing a new dimension to this relationship by influencing the oceanic food chains, water temperatures, migration patterns, sea levels, and, indeed, the fate of all the islands’ fisheries that sustain cultural traditions that honor animals and local saints. I wish to document how the Azorean People of the Whales retain their cultural survival. In so doing, I compare their efforts with those of the Iñupiaq Eskimo people of Arctic Alaska (my fieldwork site since 2004), many of whom are descents of the Azorean whalers and call themselves agviqmiut ("People of the Whales" in Iñupiaq). In this sense, my fieldwork site is not restricted in the the Azores per se, but it is also transnational and comparative for I seek to compare Azorean efforts at cultural retention with my Arctic research on humananimal relations.
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