Study highlights need for nature-based solutions to prevent climate-related losses in the city

The Hindu

22-05-2025

The Chennai Metropolitan Development Authority (CMDA) should establish a permanent nature-based solutions advisory board, and ensure that urbanising zones integrate the solutions into long-term urban planning, reducing future risks related to industrial expansion and climate vulnerabilities, according to a recommendation of a study by the Center for Study of Science, Technology and Policy (CSTEP), a Bengaluru-based think tank.
The study titled 'Urban Greenprints-Nature-based Solutions (NbS) Feasibility Framework for Urban Coastal Regions' covered 23 wards of the Greater Chennai Corporation (GCC), spanning an area of 64.35 sq.km, for their NbS potential using land-use and land-cover mapping. Key zones for intervention included residential areas, public spaces, transportation corridors, and blue-green infrastructure. Rooftops in residential zones present major opportunities for green infrastructure, with a potential to increase NbS areas in the city by 76%.
Chennai and Mangaluru were the cities selected as case studies because of their exposure to flooding, sea level rise, and extreme weather events. Permeable pavements in transport corridors could improve urban drainage, offering a 5% increase in NbS areas for both cities. Additionally, waterbodies in select wards can be fully leveraged for wetland restoration and establishing buffer zones.
The study's findings pointed to the need for developing partnerships with real estate developers and industry stakeholders to fund large-scale NbS interventions, particularly in coastal industrial zones. Collaborations among government bodies such as the Park Department of the GCC, the Tamil Nadu Forest Department, and the Tamil Nadu Wetlands Authority and private entities such as Chennai Smart City Limited and Tamil Nadu Green Climate Company can help pool resources for larger-scale NbS projects.
The study also stressed the need for coordination with neighbouring cities, such as Kancheepuram and Chengalpattu, to create a regional NbS network, which can help pool resources for larger ecosystem resilience projects and share best practices. Eco-tourism should be promoted around green spaces serving as public parks or restored wetlands such as Pallikaranai, where guided tours can attract visitors and generate income for maintenance.
The study recommended pilot projects, such as green rooftops and permeable pavements, in densely populated wards to combat storm-water runoff and mitigate the urban heat island effect. Green corridors connecting parks and open spaces along Old Mahabalipuram Road and East Coast Road, where urban expansion is intense, will be beneficial, it added.
The study said cost–benefit analysis for green rooftops and permeable pavements estimated that implementing these measures would cost ₹2,203 crore in Chennai and ₹172.97 crore in Mangaluru. In Chennai, the expected benefit from reduced flood damage and productivity losses is ₹505.31 crore every year. This means the investment would pay for itself in just over four years, the study said. Without any action, Chennai could face climate-related losses of up to ₹10,000 crore over the next 20 years, according to the study.