Shobhakar Dhakal

Planetary Stewardship in an Urbanizing World: Beyond City Limits

Cities are rapidly increasing in importance as a major factor shaping the Earth system, and therefore, must take corresponding responsibility. With currently over half the world’s population, cities are supported by resources originating from primarily rural regions often located around the world far distant from the urban loci of use. The sustainability of a city can no longer be considered in isolation from the sustainability of human and natural resources it uses from proximal or distant regions, or the combined resource use and impacts of cities globally. The world’s multiple and complex environmental and social challenges require interconnected solutions and coordinated governance approaches to planetary stewardship. We suggest that a key component of planetary stewardship is a global system of cities that develop sustainable processes and policies in concert with its non-urban areas. The potential for cities to cooperate as a system and with rural connectivity could increase their capacity to effect change and foster stewardship at the planetary scale and also increase their resource security.

Urban Energy Systems

Executive Summary More than 50% of the global population already lives in urban settlements and urban areas are projected to absorb almost all the global population growth to 2050, amounting to some additional three billion people. Over the next decades the increase in rural population in many developing countries will be overshadowed by population flows to cities. Rural populations globally are expected to peak at a level of 3.5 billion people by around 2020 and decline thereafter, albeit with heterogeneous regional trends. This adds urgency in addressing rural energy access, but our common future will be predominantly urban. Most of urban growth will continue to occur in small-to medium-sized urban centers. Growth in these smaller cities poses serious policy challenges, especially in the developing world. In small cities, data and information to guide policy are largely absent, local resources to tackle development challenges are limited, and governance and institutional capacities are weak, requiring serious efforts in capacity building, novel applications of remote sensing, information, and decision support techniques, and new institutional partnerships. While ‘megacities’ with more than 10 million inhabitants have distinctive challenges, their contribution to global urban growth will remain comparatively small. Energy-wise, the world is already predominantly urban. This assessment estimates that between 60–80% of final energy use globally is urban, with a central estimate of 75%. Applying national energy (or GHG inventory) reporting formats to the urban scale and to urban administrative boundaries is often referred to as a ‘production’ accounting approach and underlies the above GEA estimate.

Implications of transportation policies on energy and environment in Kathmandu Valley, Nepal

This paper estimates and analyzes the historical and future trends of energy demand and environmental emissions from passenger transportation of the Kathmandu Valley covering CO2, CO, HC, NOx, SO2, total suspended particles (TSP) and lead (Pb). It uses the Long-range Energy Alternatives Planning System framework for constructing future scenarios up to year 2020 and analyzing their implications; these scenarios mainly deal with the traffic improvement measures, promotion of public transportation and electric vehicles. The results estimate over a four-fold increase in energy demand in 1988–2000. TSP increase of 4.5 times in this period is the major concern since high particulate concentration is already above World Health Organization guidelines. Under the non-intervention scenario, energy demand in 2020 is estimated to be 2.7 times that in the year 2000. Similarly, 2.5 times increase of TSP in 2020 from the year 2000 is estimated that would further increase the TSP concentrations. The scenario analyses suggest that increasing vehicle speed, promoting public transportation and promoting electric vehicles could reduce energy demand by 28%, 28% and 18%, respectively, while promoting a reasonably comfortable condition on overcrowded public transportation could increase energy demand by 10% from non-intervention scenario. For TSP, any future measures would not be enough unless the attention is not paid to in-use vehicle stock. A mix of all the policies mentioned above has potentials to cut down CO2 emissions to over 60% from the non-intervention case in 2020.

Improvement of urban thermal environment by managing heat discharge sources and surface modification in Tokyo

This paper analyzes the implications of anthropogenic heat discharges into the urban thermal environment of Tokyo. Heat discharges by the representative office, commercial and residential buildings were simulated with the help of the DOE-2 building energy simulation model. The approach used in this paper also takes into account the heat storage within building structures. The geographical information system based technique was used to estimate the heat discharge distribution all over Tokyo. The mesoscale analyses of the urban climate were carried out with a model that was based on the Colorado State University Mesoscale Model. The improvements in the urban thermal environment via the various measures were analyzed for two types of scenarios, namely, scenarios related to the management of heat discharge sources and urban surface modifications. The maximum improvement in average temperature for daytime was found to be 0.47°C (at noon) as a result of greening the areas around the buildings of Tokyo. Similarly, the maximum improvement in average temperature for the evening was found to be 0.11°C by discharging all heat to the ground.

Six research priorities for cities and climate change

Xuemei Bai and colleagues call for long-term, cross-disciplinary studies to reduce carbon emissions and urban risks from global warming. Xuemei Bai and colleagues call for long-term, cross-disciplinary studies to reduce carbon emissions and urban risks from global warming.

Climate Change and Cities: The Making of a Climate Friendly Future

Publisher Summary The urban development path adopted by urbanizing regions, more specifically by cities, is a crucial factor in determining the scale and choice of energy use and the accompanied emissions of local air pollutants and greenhouse gases. Such pathways also impact on urban carbon sinks and play a significant role in determining the vulnerabilities of cities to the impacts of climate change. The connections between cities and climate change are not straightforward; understanding the drivers that explain such pathways is important to finding appropriate solutions. Above all, governing climate change at the city level and implementing measures for climate change are daunting tasks given that cities are primarily focused on local issues. However, climate change is already occurring and there is an urgent need to clarify and communicate how cities in developing and developed countries can contribute to lessening the causes and impacts of climate change from their respective levels. Cities and climate change interlinkages manifest themselves in several forms. For a long time, the focus of such interactions in climate policy debate has been one-sided, i.e. the impact of cities on climate through emissions of energy-related greenhouse gases. Cities are increasingly affected by the physical impact of climatic change such as the heightened frequency of adverse climate effects—flooding, hurricanes, infrastructure damage, etc.—and the socio-economic impacts of such consequences. In addition to the implications of impacts of physical climatic changes, cities will be increasingly affected economically, socially and environmentally, though indirectly, due to the requirements of international climate regimes, increasingly low emission technologies, growing carbon markets, technology transfers, and financial mechanisms.

Challenges of Urban and Regional Carbon Management and the Scientific Response

Abstract How urbanization unfolds in the text few decades and which urban development path we choose are potentially critical to the efforts aimed at stabilizing greenhouse gas emissions. However, our understanding of urban, as a unit or system, and its cross-scale linkages in the context of carbon management is at infancy state. In this context, this article outlines, the key challenges and introduces a new scientific initiative - Urban and Regional Carbon Management Initiative of the Global Carbon Project, which has raised key scientific questions with the aim to find reasonable answers. This article mainly showcases key science questions, past activities and future outlook with the aim to reach out to the related scientific and policy communities.

Locking in positive climate responses in cities

Well-intended climate actions are confounding each other. Cities must take a strategic and integrated approach to lock into a climate-resilient and low-emission future.

Impacts of urbanization on national residential energy use and CO2 emissions : Evidence from low-, middle- and high-income countries

Despite several previous studies, the potential differential impact of urbanization on energy consumption and CO2 emissions across stages of development has rarely been investigated. This paper attempts to fill this knowledge gap by examining the influence of urbanization on national residential energy use and emissions in low-, middle- and high-income countries. Using the Stochastic Impacts by Regression on Population, Affluence and Technology (STIRPAT) model and a sample of 88 countries for the period 1975?2005, interestingly, the results suggest that urbanization decreases residential energy use in the low-income countries, while it increases residential energy use in the high-income countries. In the middle-income countries, household energy consumption first falls and then rises with urbanization with a turning point at about 70%. Conversely, based on a sample of 80 countries over the same period, this study shows that urbanization increases residential emissions in the low- and middle-income countries, whereas the residential emissions of the high-income countries rise initially and decline subsequently with urbanization with a turning point at around 66%. These findings imply that urbanization brings with it both costs and benefits. These tradeoffs should be considered in future discussions of global energy and climate change policies.

Estimation of heat discharges by residential buildings in Tokyo

Residential buildings are one of the important parts of the urban system. They are dense in the mega-cities such as Tokyo. This paper has analyzed the residential buildings and floor area distribution for Tokyo 23 wards. Methodology was formulated, based on the DOE-2.1E building energy simulation model, to estimate the heat discharges from residential buildings to the outside environment for a representative detached house and an apartment building by accounting for the heat storage within the building structures.