Evaluating Climate Change Mitigation & Adaptation Potential of Sustainable Urban Transport Measures in India

Abstract

The global climate is transforming due to increased GHG emissions. Globally, the response to climate change has been through mitigation to reduce greenhouse gas emissions. Urban transportation is the second leading source of carbon dioxide (CO2) emissions due to its dependency on fossil fuels. The growing number of vehicles and road infrastructure-based supply in Indian cities is viewed as the essential driver of climate change and relevant consequences affecting cities’ sustainability. Under the 2015 Paris agreement, India had declared its Intended Nationally Determined Contribution (INDC). INDC aims to curtail the greenhouse gas (GHG) emission intensity of its Gross Domestic Product (GDP) by 33-35 % by 2030 from the 2005 level. Despite the mitigation measures being taken, some climate change effects are inevitable due to the constant feeding of emissions into the atmosphere. One of these climate change effects is the severe and extreme precipitation resulting in flooding. The uncontrolled expansion of human-made structures is creating more impervious urban areas. These changes, coupled with intense rainfalls and inadequate flood channelling infrastructure, lead to urban flooding. Adaptation is seen as the necessary tool to address these climate change effects. The combined impact of flooding, rapid urbanization and vehicular growth has become a looming threat to the transportation system. These factors affect developing economies disproportionately. There is an urgent need for the transport infrastructure to adapt to these climate change effects to reduce human and economic losses. In the present study, sustainable transport measures were analyzed to understand the urban transport sector’s emission mitigation potential for the pollutants CO, HC, NOx, CO2, and PM2.5. Suitable policies were identified under the planning, regulatory, economic and technological instruments grouped under four policy bundles. The policy bundles’ mitigation potential is quantitatively evaluated in terms of Vehicle Kilometers Travelled (VKT), exhaust emissions, and greenhouse gas emissions. The study also estimated the carbon emission intensity and consumer surplus for different mode users associated with the policy bundles. The findings from sustainable transport scenarios for the design years 2030 and 2050 are compared with business as usual (BAU) scenarios of the respective design years. Policy bundle 4 - a mixture of policies from all the instruments, including technological improvements such as electrification of all buses and cars in the city - demonstrated a critical decrease in VKT and emissions when compared with the other policy bundles. This study provides good scientific decision support for transport policymakers. These mitigation strategies have a disproportionate effect on the income-gender groups. The emissions contribution is non-uniform across income levels and gender. It is imperative to understand the emissions contribution of these groups for achieving equity in urban transport policies. For this purpose, the CO2 and PM2.5 emissions from a combination of eight income-gender groups together are estimated for four urban transport mitigation policy bundles. Further, each mitigation policy bundle’s emission potential for each income-gender group is calculated by comparing emissions from each policy bundle with respective BAU scenario emissions. To better understand the effects of mitigation policies on each income-gender group, specific travel parameters such as mode share, average trip length, and vehicle kilometers travelled are also assessed. Bundle 4, a blend of planning, regulatory, economic and technological policy instruments, showed the highest mitigation potential across all income-gender groups. The study finds that most female groups showed the highest mitigation potential for both pollutants for 2030 and 2050. Next, a methodological approach to formulate the adaptation strategies from urban transport to urban flooding in developing economies is presented. Additionally, adaptation strategies are evaluated based on various parameters to reduce the impact of flooding. The policies specifically aim to enhance the transportation system’s resilience to urban flooding, which is a likely consequence of climate change. Further to reduce its impacts and strengthen the urban transportation system’s adaptive capacity. This study showed that a proper combination of land use and infrastructure policies such as Bundle 1 would improve urban transportation’s resiliency to a greater extent. Further, this study developed a composite adaptability index (CAI) to assess the urban transportation system’s adaptability to urban flooding. The assessment is based on three main factors: exposure, susceptibility, and resilience. CAI tested on three adaptation policy bundles designed to improve the resiliency of urban transportation system compared to business as usual scenario for the years 2030 and 2050 in Bangalore, India. Testing of CAI showed that all the adaptation bundles showed increased adaptability. Overall, bundle 1 gave the best CAI values of 0.662 and 0.660 for 2030 and 2050, respectively and a 2% gain from the BAU scenario. The significant contributions from this work are that this study developed a framework to integrate mitigation policies, travel demand models, Delphi approach, carbon emissions intensity and consumer surplus to assess the impact of mitigation policies on emissions reduction and economic losses/gains of the commuters; the mitigation potential of eight combinations of the income-gender groups is evaluated, which provides a pathway for the research related to equity in urban transportation emissions; a methodological framework is developed to assess the climate change adaptation strategies and estimated the change in the impact of the urban flood on the urban transport system, specifically for developing economies; developing composite adaptability index which can assess the adaptability of the urban transportation sector to climate change adaptation strategies.