Global warming and climate change have become existential problems for humanity today. We are already experiencing their irreversible effects. More dangerous, catastrophic climate impacts are inevitable if we keep going without any restraints. Unrestricted Green House Gas (GHG) emissions, in the next 3 to 5 decades, shall raise the average earth temperature, melt the ice caps, cause forest fires, endanger land and aquatic species and raise sea levels, submerging several coastal cities.
CO2 concentration in the atmosphere will also cross the 500 ppm mark. Existing urbanisation models are not suitable at Indian scale due to its unprecedented population growth and there are no off-the-shelf algorithms for India. We need to chart our own path of sustainable growth. Decarbonisation is the only way forward. Climate change and global warming are interconnected. Assessing GHG emission will help developing mitigation strategies for global warming and optimisation of natural resources. This in turn compliments evolving a sustainable infrastructure.
The construction industry consumes enormous amounts of energy. The operative phase of a building’s life span is very large and consumes high energy but is distributed over a design period of about 60 years.
Energy consumption during this phase is more or less streamlined due to advanced technologies, efficient gadgets and building automation systems. GHG emissions are observed to be very high during the actual construction, resulting in what is called Carbon Spike Phenomena (CSP).
In the global scenario, buildings, industries, transport and other sectors consume 31%, 27%, 28% and 14% of total energy produced and emit 29%, 35%, 22% and 14% CO2 respectively. Out of the total GHG emission, 8 to 10% is by cement manufacturing industries. This is mainly due to heating of kiln furnaces up to 1500 deg. C using enormous amount of fossil fuel. Laudably, many cement manufacturers now are constantly striving hard to optimise and refine the manufacturing processes. It is recorded that GHG emission due to one tonne of manufactured cement varies from 0.65 to 1.0 tonne of CO2 equivalent.
About 70% of Indian population still lives in rural areas and looking forward to migrate to nearby cities. This migration puts enormous pressure on limited land mass and available infrastructure in cities. It is projected that by 2050, India will experience one of the most dramatic transitions seen in human history, causing urban population to swell from current 300 million to 700 million. Mumbai-Nasik-Pune, NCR and Greater Kolkata are expected to be the three largest urban concentration corridors in the world.
Rural migration occurs for two important reasons. Firstly, due to climate-induced impacts including floods, droughts, storms etc., and migrants are termed as environmental refugees. This group will face a different set of problems in the urban scenario in terms of housing and other facilities. Secondly, migration in search of better lifestyle, education, comfort and safe living. This group will contribute to greenhouse gas emission, adding to global warming.
The need of the hour is to become sensitive to the impacts of climate change and global warming, to evolve a road map of achieving sustainable growth and to develop right mitigation strategies to decarbonise.
The author is past president of ACCE (I)
