Greenhouse Gas Emissions In Cities Research Articles

THE PERFORMANCE OF KUALA LUMPUR’S CARBON EMISSIONS IN THE CONTEXT OF URBAN PLANNING

Cities are responsible for 70% of greenhouse gas (GHG) emissions on a global scale, and cities play an important role in reducing GHG emissions. It is essential for Kuala Lumpur to consider reducing the city's GHG emissions. The city's GHG emission inventory can track and monitor the effectiveness of the climate action plans that has been implemented. The aim of this study is to identify the performance level of GHG emissions in Kuala Lumpur between 2010 and 2019. It is also to identify the performance of Kuala Lumpur's GHG emissions in 2019 in comparison to the global and Malaysian level. Data is calculated using the Global Protocol for Community-Scale Greenhouse Gas Emissions Inventory (GPC), which is recognised and utilised globally. Secondary data for the years 2010 and 2019 was analysed as well as the performance of the Kuala Lumpur GHG emission profile in 2019. With three (3) identified sources of emissions, Kuala Lumpur managed to reduce its GHG emission intensity from 2010 by 74.07% in 2019. The city's GHG emission was recorded at 15,675 ktCO2eq in 2019. The stationary energy sector contributes higher GHG emission than other sector, with 12,043 ktCO2eq (76.83%), followed by the transportation sector with 3,180 ktCO2eq (20.29%) and the waste sector with 452 ktCO2eq (2.88%). As of 2019, Kuala Lumpur's absolute carbon contribution to the global average is 0.03%, whereas Malaysia's absolute carbon contribution is 4.74%. Additionally, the city contributes just 0.07 kgCO2eq/RM (30.17%) to Malaysia's total GHG emission intensity.

Quantum-Inspired Vehicle Routing Scheme for Rebalancing in Bike Sharing Systems

Bike sharing systems (BSSs) are gaining popularity worldwide, and with the rise of global warming, they have become even more critical for reducing greenhouse gas emissions in cities. One of the key operations of a BSS is rebalancing, which involves maintaining the number of bikes at each station to a target value by arranging vehicle loading and unloading operations. This paper proposes a quantum-inspired vehicle routing scheme to solve the rebalancing problem in BSSs. The problem is modeled as a variant of the Traveling Salesman Problem (TSP), which is an NP-hard problem that is computationally difficult to solve. The proposed approach formulates the problem as a Quadratic Unconstrained Binary Optimization (QUBO) model, which can be solved using a digital annealer. The proposed scheme’s performance is evaluated on the Fujitsu digital annealer and compared with the proposed greedy algorithm. The experimental results show that the proposed approach outperforms the greedy algorithm in finding a better feasible solution.

On the Future of Passenger Mobility and its Greenhouse Gas Emissions in Cities: Scenarios for Different Types of Policies

On the Future of Passenger Mobility and its Greenhouse Gas Emissions in Cities: Scenarios for Different Types of Policies

Detecting Patterns in Energy Use and Greenhouse Gas Emissions of Cities Using Machine Learning

Cities are expected to play a major role in managing climate change in the coming decades. The actual environmental performance of urban centres is difficult to predict due to the complex interplay of technologies and infrastructure with social, economic, and political factors. Machine learning (ML) techniques can be used to detect patterns in high-level city data to determine factors that influence favourable climate performance. In this work, rough set-based ML (RSML) is used to identify such patterns in the Sustainable Cities Index (SCI), which ranks 100 of the world’s major urban centres based on three broad criteria that cover social, environmental, and economic dimensions. These main criteria are further broken down into 18 detailed criteria that are used to calculate the aggregate SCI scores of the listed cities. Two of the environmental criteria measure energy intensity and greenhouse gas (GHG) emissions. RSML is used to generate interpretable rule-based (if/then) models that predict energy utilisation and GHG emissions performance of cities based on the other criteria in the database. Attribute reduction techniques are used to identify a set of 7 non-redundant criteria for energy use and 9 non-redundant criteria for GHG emissions; 6 criteria are common to these two sets. Then, RSML is used to generate rule-based models. A 10-rule model is determined for energy intensity, while an 11-rule model is found for GHG emissions. Both models were reduced further by eliminating rules with weak generalisation capability. A key insight from the rule-based models is that social, environmental, and economic attributes are associated with energy intensity and GHG emissions due to indirect effects.

Decoupling density from tallness in analysing the life cycle greenhouse gas emissions of cities

The UN estimate 2.5 billion new urban residents by 2050, thus further increasing global greenhouse gases (GHG) emissions and energy demand, and the environmental impacts caused by the built environment. Achieving optimal use of space and maximal efficiency in buildings is therefore fundamental for sustainable urbanisation. There is a growing belief that building taller and denser is better. However, urban environmental design often neglects life cycle GHG emissions. Here we offer a method that decouples density and tallness in urban environments and allows each to be analysed individually. We test this method on case studies of real neighbourhoods and show that taller urban environments significantly increase life cycle GHG emissions (+154%) and low-density urban environments significantly increase land use (+142%). However, increasing urban density without increasing urban height reduces life cycle GHG emissions while maximising the population capacity. These results contend the claim that building taller is the most efficient way to meet growing demand for urban space and instead show that denser urban environments do not significantly increase life cycle GHG emissions and require less land.

The impact of low-carbon city pilot policy on the total factor productivity of listed enterprises in China

In recent years, the low-carbon city pilot policy has been important work in China. It aims to control the city's greenhouse gas emissions, find a "win-win" path of low-carbon and economy and drive the innovation and development of cities through low-carbon goals. In this context, we consider the low-carbon city pilot policy as the starting point. Based on the data of A-share listed companies in Shanghai and Shenzhen from 2005 to 2015 in 285 prefecture-level cities, the OP and LP methods are used to calculate total factor productivity (TFP). In this paper, using PSM-DID and other methods, we empirically test whether and how the low-carbon city pilot policy affects enterprise TFP. The results indicate that the construction of low-carbon cities significantly promotes an increase in the TFP of local enterprises. In addition, improving technological innovation and optimizing the efficiency of resource allocation are two important transmission mechanisms. The above conclusions are robust to a series of tests. Therefore, the implementation of a low-carbon city pilot policy can help achieve the "win-win" goal of emission reduction and high-quality enterprise development. This study provides strong support for further expanding the scope of low-carbon city pilot policy projects and the scientific implementation of climate change policies, and it provides beneficial policy enlightenment for the scientific implementation of urban emission reduction control to win the battle against climate change.

Carbon sequestration and storage potential of urban green in residential yards: A case study from Helsinki

Cities have been identified as key actors in climate change mitigation. Nature based carbon sinks have been suggested as a means of mitigating the greenhouse gas emissions of cities. Although there are several studies on the carbon storage and sequestration (CSS) of urban green, the role of residential sites is not fully understood. In addition, the carbon storage of soils is often excluded. Also the implications for planning require more attention. This study estimates the CSS potential of trees and biochar in urban residential yards and identifies effective means to enhance it. Moreover, the study discusses the results at the city scale. The research is based on a case study in Helsinki, Finland, and applies i-Tree planting tool to assess the current and potential life cycle CSS of the case area. The results reveal that trees and the mixing of biochar into growing medium can increase the CSS considerably. The CSS potential of the case area is 520 kg CO2 per resident during 50 years. The added biochar accounts for 65 % of the capacity and the biomass of trees accounts for 35 %. At the city scale, it would lead to 330 000 t CO2 being stored during 50 years. The findings suggest that green planning could contribute more strongly to climate change mitigation by encouraging the use of biochar and the planting of trees, in addition to ensuring favourable growing conditions.

Future city visions. The energy transition towards carbon-neutrality: lessons learned from the case of Roeselare, Belgium

As climate change develops, with most of the world population living in urban areas, decarbonisation of cities is among the greatest challenges of the coming decades. In the framework of the EU City-zen project, a number of so-called Roadshows has been organised in ten cities within and outside Europe in order to plan and kick-off their transition towards an energy- and climate-neutral economy. During the Roadshows, a group of experts is engaged to perform co-working activities and participative labs involving local stakeholders. These activities support cities in identifying their own decarbonisation pathways, mainly by combining three mutual processes, i.e. energy design, urban design and carbon accounting. The latter, in particular, has been used to quantify the greenhouse gas emissions of cities and neighbourhoods and to estimate the mitigation effect of a combination of measures towards the desirable condition of carbon neutrality. This exploratory and proactive design process has been successfully demonstrated through intensive workshops and can be potentially replicated in other cities. This paper provides a schematic overview of the main results achieved in the Belgian town of Roeselare, but more significantly it describes the techniques needed to make that cooperative process understandable, impactful and implementable. It is likely that 2050 European goals will drastically change urban environments and socio-economic dynamics in cities, due to the fragmentation of energy sources. Hence, from this standpoint there is a vital need for integrated technologies and infrastructures, a circular economy and community-based processes such as food production, sharing of facilities and valorisation of ecosystem services. The City-zen Roeselare Roadshow brought over 300 stakeholders into the process of re-imagining and visualising their 2050 future city with these solutions. Stakeholders, with no particular expertise in carbon accounting or sustainability, would now have the capability of understanding and applying these solutions in a combined effort to meet the zero-carbon challenge. The approach is generally replicable elsewhere being highly visual, impactful, transferable, and multi-stakeholder friendly. Given that data are made locally available, the combination of this general approach, site-specific assessments and the involvement of both experts and local stakeholders (i.e. policy makers, citizens, etc) allow the transition to start by referring to any real city or neighbourhood.

Empirical study on carbon emission measurement and influencing factors of urban traffic based on “Population-Economy-Environment”

Economic growth, urban expansion, traffic dependence, and urban lifestyle have caused a large amount of energy consumption and greenhouse gas emissions in cities. The issue of urban greenhouse gas emissions has become a global focus and a research hotspot. This paper analysed the causality of driving factors and identified the key elements such as urban population, economy, energy and motor vehicles through system dynamics (SD) and econometric model. Then, it conducted empirical analysis and explored the impact of factors on urban transportation carbon emissions taking Beijing as an example. The research results showed that in addition to energy consumption, other factors were positively correlated with traffic carbon emissions. It believed that in order to control urban traffic carbon emissions, we must control the urban population, economy and the number of vehicles rationally. With the optimization of energy structure, the structural adjustment of traffic energy consumption is conducive to energy conservation and emission reduction in the transportation industry, and the decoupling of the total energy consumption of traffic and the carbon emissions from transportation.

On the definition and prioritization of strategies and actions to minimize greenhouse gas emissions in cities: An actor-oriented approach

Cities as hotspots of human economic activity and infrastructures provide some of the best opportunities for decarbonizing sectors essential for limiting the global warming to 1.5, such as buildings and transport. For this reason, regulators and researchers have widely recognized the necessity to put cities, as an important object of assessment, and city authorities, as an important actor group, at the core of climate mitigation efforts. In their pursuit of a low-emission future, however, cities are confronted with a number of theoretical and practical questions regarding allocation and accounting of city-related greenhouse gas (GHG), target setting and subsequent planning for mitigation. A wide literature is currently focused on the first two. However, to achieve ambitious climate targets, research should urgently focus more on how to reap all available urban mitigation actions and encourage rapid and radical changes. Identifying and prioritising mitigation strategies and actions to achieve the targets, as well as putting them together into a coherent plan with a clear vision of the future, are critical steps in actionable and effective climate action planning. As a first contribution in this direction, this paper provides recommendations for research and practice to support a more integrated and conscious definition and prioritization of actions by municipal stakeholders, based on: (1) the specific context of each city type as a determinant of what actions may work, (2) the executive power of city authority to act as the main actor and (3) the multiple benefits and/or trade-offs accruing from each local climate action.

Intellectual analysis and estimation of gross greenhouse gas emissions

Currently, the system of accounting and monitoring of greenhouse gas emissions is being formed in the Russian Federation. It should be noted that within the framework of the system being formed, the transport sector is considered as the main contributor that generates large amounts of greenhouse gas emissions in cities and on busy federal highways. At the same time, it is proposed to take into account emissions directly when burning fuel only by road, city electric, rail, water and air transport. The article discusses methods for estimating gross emissions from road facilities using data mining methods aimed at verifying the results obtained. The article also presents the calculation of greenhouse gas emissions for road facilities in the pilot region with a description of the verification algorithm for the results obtained. The results of testing the methods for determining greenhouse gas emissions by road facilities showed that this calculation method can be used in estimating greenhouse gas emissions at road facilities, however, reliable baseline data for calculating gross greenhouse gas emissions can only be obtained by analyzing the activities of economic entities in transport and in the road sector. It should be borne in mind that business entities are not obliged to provide information constituting commercial secrets from their point of view. Therefore, the results obtained are of an estimated nature and relate only to those objects, data on which could be obtained from official statistics and free sources, while the actual amount of greenhouse gas emissions from road facilities in the pilot region during the period under review may be significantly higher.

Evaluation of urban road trees in terms of ecosystem services according to climate change scenarios and species distribution model: The case of Robinia pseudoacacia L.

Ulaşımın temel işlevlerine göre hareket, erişim ve yaşamın bir parçası olan yolların çevresinde dinamik, ekolojik ve estetik özellikleri ile yer alan ağaçlar kentsel yeşil alanların önemli bileşenleri arasındadır. Bu alanların fonksiyonları ve estetik özellikleri planlama ve tasarımda kullanılan bitkilerin formları, dokuları ve estetik fonksiyonları ile doğru orantılı olarak şekillenmektedir. Kentsel yol ağaçlandırma çalışmalarında bitkilerin ya da kullanılan canlı materyalin estetik ve fonksiyonel özelliklerinin yanı sıra ekolojik özellikleri ve yetişme koşulları ile de ele alınması bu çalışmaların sürdürülebilirliği bağlamında gereklidir. Öyle ki kentlerde artan sera gazı emisyonları sonucunda küresel ısınma, öncelikle yaşadığımız çevre, sonrasında ise tüm dünya için tehdit oluşturmaktadır. Küresel ısınmanın bir sonucu olarak iklim değişimi bugün dünya üzerindeki tüm canlıları etkilemekte ve doğanın dengesini değiştirmektedir. Doğanın dengesinin bozulması, içindeki tüm canlı unsurların değişim ve dönüşümünü ifade ederken insan refahı, ekosistem hizmetleri ve biyoçeşitlilik bağlamında da ciddi kayıplar anlamına gelmektedir. Çalışmanın amacı, ülkemizde kentsel yol ağaçlandırmaları çalışmalarında yaygın olarak kullanılan Robinia pseudoacacia L.’nin iklim değişimi sonucunda yayılış alanlarındaki değişimin tür dağılım modeli ile tespit edilmesi ve ekosistem hizmetleri bağlamında değerlendirilmesidir. Tür dağılım modelini temel alan MaxEnt 3.4.1 programı kullanılarak türe ait Türkiye’deki mevcut yayılış alanları ve iklim değişimine bağlı olarak geliştirilen senaryolara göre gelecek projeksiyonu kentler ve coğrafik bölgeler bazında tespit edilmiştir. Sonuç olarak; kentsel yol ağaçlarının yayılış alanlarındaki değişim biyoçeşitlilik ve kentsel ekosistem hizmetleri bağlamında tartışılmıştır.

Using Lidar Technology To Assess Urban Air Pollution and Improve Estimates of Greenhouse Gas Emissions in Boston.

Simulation of the planetary boundary layer (PBL) is key for forecasting air quality and estimating greenhouse gas (GHG) emissions in cities. Here we conducted the first long-term and continuous study of PBL heights (PBLHs) in Boston, MA, using a compact lidar instrument. We developed an image recognition algorithm to estimate PBLHs from the lidar measurements and evaluated simulations of the PBL from seven numerical weather prediction (NWP) model versions, which showed different systematic errors and variability in simulating the PBLHs (discrepancies from -2.5 to 4.0 km). The NWP model with the best overall agreement for the fully developed PBL had R2 = 0.72 and a bias of only 0.128 km. However, this model predicted a notable number of anomalously high carbon dioxide concentrations at ground stations, because it occasionally significantly underestimated the PBLH. We also developed a novel method that combines lidar data with footprints from a Lagrangian particle dispersion model to identify long-range transport of air pollution in the nocturnal residual layer. Our framework was powerful in evaluating the performance of models used to estimate air pollution and GHG emissions in cities, which is critical to track progress on emission reduction targets and guide effective policies.

GHG evaluation and mitigation planning for low carbon city case study: Dan Sai Municipality

In the era of globalization, the economy has expanded, leading to an increase in population and the growth of the city dramatically. The municipalities as local administrators for the being and the quality of life of people in the city. However, the activities in the city such as fuel consumption of housing and transportation, electricity use, waste management like wastewater and waste produce both direct and indirect greenhouse gases, increasing many impacts of climate change. The concept of “low carbon city” has been applied to local government in Thailand. This research aims to evaluate city's greenhouse gas emissions in a case study of Dan Sai municipality based on the Global Protocol for Community-Scale Greenhouse Gas Emission Inventories guideline (GPC), divided into three scopes are scope 1, direct greenhouse gas emissions, scope 2, indirect greenhouse gas emissions from the electricity use and scope 3, other indirect greenhouse gas emissions. According to the study of the city's greenhouse gas emissions in year 2016, was found that Dan Sai municipality had a greenhouse gas emission of 22,925.66 tCO2eq, equivalent to 5.95 tCO2eq/person/year of the amount of greenhouse gas emissions per capita, The amount of greenhouse gas emissions per household is 11.84 tCO2eq/household/year and the amount of greenhouse gas emissions per area is 2,999.82 tCO2eq/square kilometer/year. And from the assessing results of the alternative options to reduce greenhouse gases by analyzing the final cost of the three options, that are increasing the number of solar rooftops, increasing the use of household LED bulbs and refining waste management using RDF technology, found that the final cost was −175.48, 87.53 and −61.72 Baht/kgCO2eq, respectively. This project model is a sustainable city developed into a low carbon city in the future.

Covenant of Mayors: Local Energy Generation, Methodology, Policies and Good Practice Examples

Local authorities and cities are at the forefront of driving the energy transition, which plays a crucial role in mitigating the effects of climate change. The greenhouse gas emissions in cities, due to energy consumption, are placed into two categories: direct emissions generated from the combustion of fossil fuels mainly in buildings and transport sectors, and indirect emissions from grid-supplied energy, such as electricity and district heating and/or cooling. While there is extensive literature focused on direct greenhouse gas emissions accounting in cities’ inventories, research has focused to a lesser extent on allocation methods of indirect emissions from grid-supplied energy. The present paper provides an updated definition for the concept of local energy generation within the Covenant of Mayors initiative and proposes a new methodology for indirect emission accounting in cities’ greenhouse gas emission inventories. In addition, a broader policy framework in which local action is taken is discussed based on the European Union energy and climate policies, and over 80 exemplary Covenant of Mayors good practices are identified across the technology areas of local energy generation and four modes of urban climate governance. The contributions of the paper demonstrate that local authorities have the capacity to support and mobilize action for local energy generation investments through the multiple modes of urban climate governance to update and strengthen climate action

A Path Walkability Assessment Index Model for Evaluating and Facilitating Retail Walking Using Decision-Tree-Making (DTM) Method

Transportation is the major contributor of ever-increasing CO2 and Greenhouse Gas emissions in cities. The ever-increasing hazardous emissions of transportation and energy consumption have persuaded transportation and urban planners to motivate people to non-motorized mode of travel, especially walking. Currently, there are several urban walkability assessment models; however, coping with a limited range of walkability assessment variables make these models not fully able to promote inclusive walkable urban neighborhoods. In this regard, this study develops the path walkability assessment (PWA) index model which evaluates and analyzes path walkability in association with the pedestrian’s decision-tree-making (DTM). The model converts the pedestrian’s DTM qualitative data to quantifiable values. This model involves ninety-two (92) physical and environmental walkability assessment variables clustered into three layers of DTM (Layer 1: features; Layer 2: Criteria; and Layer 3: Sub-Criteria), and scoped to shopping and retail type of walking. The PWA model as a global decision support tool can be applied in any neighborhood in the world, and this study implements it at Taman Universiti neighborhood in Skudai, Malaysia. The PWA model has established the walkability score index which determines the grading rate of walkability accomplishment for each walkability variable of the under-survey neighborhood. Using the PWA grading index enables urban designers to manage properly the financial resource allocation for inspiring walkability in the targeted neighborhood.

PATH CYCLABILITY ASSESSMENT INDEX MODEL USING DECISION TREE MAKING METHOD: A CASE OF DOHA-QATAR

Transportation is the major contributor of ever-increasing CO2 and Greenhouse Gas emissions in cities all around the world; while the number of vehicles is rapidly growing. Growing concern on reducing transportation hazardous emissions and securing energy sources has led to New Urbanism and Smart Growth policies declarations. The urban and transportation professionals are attempting to develop innovative techniques to change people‘s travel mode selection to less energy-intensive modes, particularly, cycling. The current research has developed an urban index assessment model evaluates and analyzes cyclability of path segments in association with residents‘ decision making in cyclable route selection, called Path Cyclability Assessment Index (PACEX). The model was developed based on decision-tree-making (DTM) method to measure the qualitative data quantifiable. The model involves ninety (90) physical and environmental cyclability variables clustered into three layers of decision-tree-making (Layer 1: Features, Layer 2: Criteria, Layer 3: Sub-criteria). Although the model is applicable in any neighborhood, this research was implemented it in Doha, Qatar where specially needs for hosting FIFA 2022. The analysis result shows the sub-criterion F1.C1.S2 Existence of Crossing mostly affects to neighborhood cyclability (24.25%), in contrast, the sub-criterion F1.C3.S7 Street Surveillance affects least (4.82%); and overall neighborhood was ranked as grade B of cyclability ranking. The model supports both personal and society needs, preferences, and priorities of cyclable environment design and development. Using this model contributes to less energy consumption, less CO2 and GHG emissions, less street fatalities and accidents, simultaneously, promotes public health. Juxtaposing using the PACEX model aids decision makers and policy makers in sustainable urban development in prioritizing the allocation of resources for development and/or redevelopment of the area concerned.

Affordable Housing and the Environment in Buffalo, New York

Buffalo is suffering from severe housing and environmental problems, many of which overlap. New housing continues to sprawl into the suburbs and exurbs, despite a large surplus of housing units in Buffalo, where the City plans to demolish 10,000 units in the next ten years. In general, housing is not being designed, built, or renovated in an environmental manner. Our out-dated housing policies and choices contribute significantly to pollution, both locally and globally: the region gets a failing grade for air quality; the city has 68 sewage overflows per year; and residential energy use is the largest source of the city's greenhouse gas emissions. Air pollution affects people with low incomes the most severely, and, with the advent of climate change, it has the potential to make millions of people homeless around the globe.Greening our state and local affordable housing policies is a win/win strategy that will reduce both pollution and poverty. If we do more realistic cost/benefit analyses that cover the whole life of the home, we will see that greener policies - especially regarding energy efficiency and alternative energy - make housing more affordable even as they lessen environmental harms. The State of New York, the City of Buffalo, and the non-profit community should adopt policies and practices that- Require and reward greater energy efficiency in housing;- Add to the incentives for alternate energy use;- Educate the public and promote energy conservation;- Promote water conservation and rain water control;- Reduce sprawl and revitalize the city;- foreclosure, disrepair, and abandonment;- Increase funding for preservation, weatherization, and renovation and prioritize them over new construction;- Prioritize deconstruction and recycling of housing materials over demolition;- Re-use vacant lots and brownfields for gardens, farms, parks, and greenways.

Evaluating transport externalities of urban growth: a critical review of scenario-based planning methods

Urban growth is an important phenomenon, which is taking place on an unprecedented scale, and its impacts on society and the environment are evident. In theory, an evaluation of such urban growth through scenario-based planning helps planners to better assess the future impacts of growth and develop better policies and plans. Within this context, the assessment of transport impacts is particularly important as transport plays an important role in shaping urban growth. Additionally, transport sector alone is responsible for about one-third of the greenhouse gas emissions of cities, which has detrimental effects on the environment, economy, community health, and quality of life. In practice, however, scarce evidence exists outlining the challenges of scenario-based evaluation and how to best address these while modelling the transport impacts of various urban growth scenarios. This research addresses these gaps in the literature and assesses the effectiveness of scenario-based planning methods that are used for modelling the transport impacts of alternative urban growth scenarios. The methodological approach of the study consists of a critical review of the key literature and relevant methods that are commonly used to assess transport impacts. The results of this analysis highlight limitations of existing methods for effectively evaluating transport externalities of urban growth scenarios. The findings suggest that among many reviewed models, the ILUTE, URBANSIM and TRANUS simulation models are identified as significant ones. However, due to various limitations of the former two, TRANUS is noted as the most suitable one for evaluating the transport impacts of urban growth scenarios.

Spatial-modal scenarios of greenhouse gas emissions from commuting in Hong Kong

Transportation is a major source of greenhouse gas emissions in cities. Multiple strategies including green technologies, transport management, urban planning and behavior changes are required to mitigate transport emissions. This paper aims to introduce an analytical framework to investigate the impacts of different spatial-modal strategies on reducing commuting emissions. Based on the optimization approach of excess commuting, the proposed framework incorporates the minimum, maximum and random (unpredictable) travel outcomes to inform planning of an urban form embedded with fewer emissions. This analytical framework is applied to Hong Kong to estimate the emissions ranges (the minimum and maximum amounts) under 42 spatial-modal scenarios - a combination of six spatial strategies (status quo, monocentric, highly polycentric, moderately polycentric, dual-centric and tri-centric) and seven modal strategies (status quo, pro-rail (high), pro-rail (moderate), pro-bus (high), pro-bus (moderate), pro-car (high) and pro-car (moderate)). The findings illustrate the emissions impacts if Hong Kong is further developed following a job concentration or decentralization principle. It also indicates that if Hong Kong is reconstructed to be a city with multiple CBDs, a dual-centric strategy is desirable because both minimum and maximum commuting are shorter than that of a tri-centric strategy. Moreover, the modal strategy to actively promote rail usage shows more impacts on emissions reduction and car usage should be maintained at the current level. If commuter's travl is less predictable, the high rail usage under a dual-centric city form is a more sustainable spatial-modal strategy. The proposed analytical framework of city's commuting emissions affected by structural and modal changes is transferrable to other places and could offer planners different benchmarks of travel pattern to substantiate their sustainable city planning vision.