For the two decades that climate change has been around in popular lexicon, the phenomenon has consumed environmentalists and a section of scientists. But it failed to elicit concrete action from global leaders, heads of states, large multi-national corporations and other agencies that collectively determine our future and that of our planet. The idea of climate change impact was initially denied by most of them.

Irrespective of the outcome in Paris, it is now imperative for countries and cities to evolve their responses to climate change impacts. Three of India’s largest and important metropolises – Mumbai, Chennai and Kolkata – are among the most vulnerable coastal cities in the world, according to studies by a range of institutions such as the World Bank, IIT Bombay and India’s official agencies.

Mumbai registered a mean temperature rise of 1.62 degrees Celsius between 1901 and 2007 and the sea level around the city is rising by 2.4 mm every year, revealed a recent study by the National Environmental Engineering Research Institute. These, together, would “unleash a chain of disasters such as flash floods, disease outbreaks, building collapses, dislocation and death,” it warned and estimated that Mumbai could face economic damages worth lakhs of crores by 2050 because of climate change.

The IIT Bombay study earlier this year warned the urban heat island effect - a phenomenon in which the city turns warmer than surrounding areas as temperature is raised by heat-absorbing concrete and asphalt, high population densities and pollution -- was evident. An independent risk analysis report in Washington placed India – and Mumbai – in the “extreme risk” category where economic impacts of climate change will be felt by 2025.

The writing is on the wall. Unseasonal rain, extreme weather events, higher summer and lower winter temperatures, thunderstorms are evidences of climate change. There must be an integrated response plan and it has to be put to work. But the state government, its multiple autonomous agencies, the municipal corporation, influencers such as the real estate lobby have been negligent or half-hearted in their attempts so far. In fact, climate change hardly ever gets time and mind space in the many discussions on Mumbai’s development.

The effort has to begin with the recognition that rapid and unsustainable urbanisation is a major cause for climate change. Cities contribute to it and suffer from its impacts. But for Mumbai, specific information has been sorely lacking. A start was made last year when the MMRDA initiated, through environment improvement society, an interactive website to provide climate change indicators, and educate people about the relationship between their life choices and climate change.

A key factor in climate change in cities is the land-use pattern. Densely built-up areas act as stressors. Mumbai’s every available inch is built upon, the real estate lobby covets more, successive governments have sanctioned buildings, infrastructure projects, and reclamations without much consideration to their impact on climate change. The Development Plan 2034 does not give importance to climate change impact, neither do landmark documents such as Vision Mumbai.

It is time urban planning seriously accounted for climate change.

Moreover, building surfaces must be regulated because it is proven that chrome and glass exteriors raise surface temperatures in a city, sometimes to 56 degrees Celsius. Large open areas and wetlands have to be increased rather than acquired for construction. The number of vehicles and their emissions must be regulated.

It may already be too late but better now than later. There is no other Mumbai.