Development, climate change and Indian cities: framing and implementing policies

Abstract

Cities in India are already experiencing enhanced climate variability and extremes in annual precipitation and temperature events. A city’s climate is affected both by global warming and local factors such as its built form and landscape, and studying their interactions therefore could generate significant value.

My first study uses Landsat satellite data (NASA) to examine the urban land use patterns for 47 cities in India across tiers and climatic zones for 1990, 2000, 2010 and 2017. The results show rising share of built-up area from 25.4% to 48% while agriculture, green and open spaces decline. Tier-level analysis indicates that tier-Y and Z cities are on a similar trajectory as tier-X cities have followed in past i.e. intensive building up of spaces. I conclude that spatial growth patterns across Indian cities represent unplanned and variable growth patterns, and cities follow a mix of ribbon development, ring radial model, and multi-nuclei approach at different points in time and locations.

My second study examines impacts of land use changes on local flooding. The historic flood events data for 42 of these cities was analyzed using statistical modelling. A decline in non-built spaces increases odds of flooding incidences in cities significantly, controlling for city level variations in rainfall. An integrated scenario matrix consisting of three urban development and four climate change storylines are assessed to estimate urban flooding events up to 2050.

The third study using satellite images (MODIS from NASA) and IMD data infers that micro climate in a city as represented by day and night land surface temperatures is a better indicator as compared to air temperature for estimating relative mortality risks. A distributed lag non-linear model was developed for Ahmedabad. With increase in built-up spaces by 1% in the land use mix, the relative risk increases by 0.59 points at 40°C and by 0.78 points at 45°C. Females, persons below 4 and above 75 years of age show increased vulnerability. Overall, the three studies highlight that Indian cities should undertake integrated spatial policies and measures for climate resilient and sustainable urban development.