Indian Institute of Technology Madras (IITM) researchers predict Chennai could cumulatively emit over 231.9 million tonnes of carbon dioxide (CO2) by 2040 from the construction and building operations alone, owing to rapid urbanisation.

The researchers suggest switching to renewable sources of energy for buildings’ operational requirements, a key driver to reduce emissions.

The study was conducted by a team of researchers from the Centre for Technologies for Low Carbon and Lean Construction, IIT Madras, and the Indo-German Centre for Sustainability (IGCS), comprising Ashwin Mahalingam, Department of Civil Engineering, IIT Madras, and Pokhraj Nayak, a former student of the institute.

Rapid urbanisation is likely to lead to an increase in built stock across the country. In India, the building industry accounts for a quarter of total CO2 emissions. This is primarily due to the emissions from raw material production such as cement and seel, their transportation, and the energy used during building operations, says a release.

For the first phase of the study, the researchers used geo-spatial land models developed by The Nature Conservancy - a global environmental non-profit organisation and used simulation techniques to develop a futuristic map of Chennai in 2040 taking into account the past trends and future constraints.

The model showed an increase in urban built-up areas is accompanied by decrease in water tables and wetlands.

The researchers found that the single-largest contributor to reduce emissions is to change the energy source. The clean energy usage in 50 per cent of a building’s operational needs is likely to result in a corresponding reduction in cumulative CO2 emissions of up to 115 million tonnes between 2019 and 2040. Replacing traditional cement with low carbon cement had a lower impact in reducing emissions, the release added.