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How to mitigate urban emissions

According to the latest report by International Panel on Climate Change, in 2020, total urban emissions (including CO2 and CH4) derived from consumption-based accounting were estimated to be 28.5 ± 0.1 GtCO2-eq, representing between 67% and 72% of global CO2 and CH4 emissions, excluding aviation, shipping, and biogenic sources of emissions. By 2050, with no or moderate urban mitigation efforts, a possibility which cannot be entirely ruled out, urban emissions are projected to rise to 34–65 GtCO2-eq—driven by growing urban population, infrastructure, and service demands. India will be at the forefront of global economic growth and faster urbanisation is one of the means to achieve this higher growth. But urbanisation will come at a cost, which will be huge one unless handled properly.

Urban land area expansion

Urban land area (sq. km) in India was reported at 222688 in 2010, according to the World Bank collection of development indicators. In next few decades the urban population will almost double while the urban area may not increase proportionately which may become one of the root causes of our many problems.

Various studies suggest that the United States, China, and India will experience continued urban land expansion at least until 2050. However, after 2050, China could experience a decrease in the rate of urban land expansion, while growth may continue for India. This is because India’s urban demographic transition will only get underway after the middle of the century, when the urban population is expected to exceed the rural population. In contrast, China’s urban demographic transition could be nearly complete by 2050.

As urban clusters increase in size and green space is converted, future urban land expansion is expected to intensify urban heat islands and exacerbate night-time extreme temperatures. Furthermore, forecasts also reveal that the urban expansion-induced warming is on average about half—and in certain locations nearly twice—as strong as warming that will be caused by GHG.

Absence of a comprehensive spatial development strategy leads to multiple issues, for example, lack of land for affordable housing, flooding, traffic jams, and wastage of water resources. Moreover, once the city has grown haphazardly, corrective measures and provision of infrastructure are difficult and costlier to undertake. The process of designing a city master plan needs financial and human resources.

Tackling the carbon lock-in risk

One of the greatest risks we will be facing because of rapid urbanisation is the threat of carbon lock-in. Carbon lock-in refers to the self-perpetuating inertia created by large fossil fuel-based energy systems that inhibits public and private efforts to introduce alternative energy technologies. Cities are especially prone to carbon lock-in because of the multiple interactions of technological, institutional, and behavioural systems, which create inertia and path dependency that are difficult to break. For example, the lock-in of gasoline cars is reinforced by highway and energy infrastructures that are further locked-in by social and cultural preferences for individual mobility options. The dominance of cars and their supporting infrastructures in auto-centric urban forms is further reinforced by zoning and urban development patterns, such as dispersed and low-density housing distantly located from jobs, that create obstacles to create alternative mobility options.

Carbon lock-in threat posed by urban infrastructures and the built environment is even greater and long lasting. These are long-lived assets, embodying triple carbon lock-ins in terms of their construction, operations, and demolition. There is much focus in the climate change literature on the operational lifetimes of the energy sector, especially power plants and the electricity grid, which are between 30 and 60 years. Yet, in reality, the lifespans of urban infrastructures, especially the basic layout of roadways, are often much longer. A number of detailed case studies on the evolution of urban road networks for cities around the world reveal that the current layout of streets grew out of street networks that were established hundreds of years ago. Furthermore, there is evidence that urban street layout, population growth, urban development, and automobile ownership co-evolve.

For our cities to break out of mutually reinforcing carbon lock-in, it will require systematic transformation and systems-based planning that integrates mitigation strategies across sectors.  Urban energy demand patterns are locked-in whenever incremental urban design and planning decisions, coupled with investments in long-lasting infrastructure, such as roads and buildings, take place. The fundamental building blocks of cities are based on the layout of the street network, the size of city blocks, and the density of street intersections. If not significantly altered, these three factors will continue to shape and lock-in energy demand for decades after their initial construction, influencing the mitigation potential of our urban areas.

Avoiding carbon lock-in inherently involves decisions that extend beyond the administrative boundaries of cities and often beyond the control of urban local bodies. This includes pricing of low-emissions technology or materials, such as electric battery or hydrogen vehicles and buses State governments do have powers to set building codes that regulate materials and construction standards for buildings, including heating and cooling technologies, and major appliances. Other examples include zoning that determines the location of buildings, land uses, standards for densities, and the inclusion of energy planning in their building standards and public works, including streets, parks, and open spaces.

Our objective should be creation a ‘healthy living environment’ by focusing on citizens’ well-being, including physical and mental health, and measures to achieve cleaner air, water and soil as well as parameters to ensure a balance between the built and unbuilt environments. The lessons that we have learnt in the last two years or so need to be implemented now.

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