Microclimate zones determine the temperature in your neighbourhood.
Have you wondered why the meteorological department’s maximum and minimum temperatures seems to be at variance from one part of the city to another? Some places are noticeably hotter than what the weather reports indicate, while others are much cooler by a few degrees.
What explains this variation? Is it for real, or is it a matter of individual perception? An analysis of temperatures across Mumbai last year by Pune-based environment consultants Respirer Living Sciences (RLS) indicates that microclimate zones are forming within the city. According to the study this calls for a localised approach to mitigating heat stress. It cannot be a one-size-fits-all approach for Mumbai or, for that matter, any of the other metros.
The variations in temperature were quite remarkable. The RLS analysis observed that a suburb like Ghatkopar with its dense population recorded a mean temperature of 33.3 degrees Celsius between March 1 and March 22 last year, while Powai which has fewer high rises, less population, and lot of greenery recorded an average temperature of 20.4 degrees during the same period. That is a difference of 13 degrees Celsius!
Environmentalists are agreed that such temperature variations are linked to microclimate zones being formed within a city. These are small, localised areas differing in climate conditions from the broader region. Such microclimate zones are formed due to various factors including density of population and vehicular transport, prevalence or absence of vegetation, number of concrete buildings and industrial units.
Ronak Sutaria, CEO of RLS was quoted in the media as saying that microclimate zones forming within cities like Mumbai is a reality that cannot be ignored because it has considerable health impact on the residents of a particular area. This local variation in the temperature may not be reflected in the average temperature recorded in a city.
As citizens what can we do to ensure that our cities do not turn into urban heat islands (UHI) — or urban areas that exhibit markedly higher temperatures than their surrounding rural zones. At the local level, how can we influence the microclimate in our workplaces and in the residential areas we live in.
Drawing up urban development plans, understandably, is a macro activity that is beyond our control. The most we can do is pressurise town planners and government agencies to keep the urban heat factor in mind while clearing mega constructions and industrial units. We can also push for and support environment-friendly actions like saving the mangroves along the coast and protecting our forests.
But at the micro level we can do our bit to keep our environment green, healthy and cool. Of course, there is no magic formula that will usher in change overnight. But here are a few suggestions from experts on specialised websites:
Plant as much greenery as possible: It would be a good idea to plant resilient native trees which provide shade near windows and paved areas to block the heat.
Those living in apartments can grow potted plants, shrubs, or small bushes on their balconies and porches. They could encourage others to do so as well.
It would be great if residents could persuade their Resident Welfare Associations to create rooftop gardens or green roofs that absorb heat to bring down temperatures in buildings in the community. They could even install vertical green walls on building surfaces that catch the sunshine.
There are a few ways to cool surfaces and homes. The most popular is by painting roofs and exterior walls with reflective white or light-coloured paint. At the same time, it would be a sound idea to replace concrete or dark asphalt yards with either of the three — grass, gravel, or permeable pavers. Another layer of coolness can be achieved by keeping the soil damp by watering plants during the early morning or evening hours.
It is not very difficult to do your bit to reduce the local heat and the pollution. Environmentalists suggest that you walk, cycle, or use public transport instead of driving cars to cut waste heat. Within the household, turn off unused electrical appliances and air conditioners that vent hot air outside.
And if you take the trouble to support neighbourhood parks and community tree-planting programmes, you will win many hearts. In Chennai, where I live, there are several community initiatives of citizens coming together to green the commons, water roadside shrubs or clear the parks and pavements. These have got considerable recognition and all for the right reasons.
But, if we go one step further, and also take a look at the shanties and clusters around our colonies, we would be furthering our effort to cool the city. In the not so well to do quarters, the population lives in low-roofed dwellings often made of tin or asbestos. These packed structures have a ventilation deficit, and the cooling effect of trees and vegetation is virtually absent. Studies across Mumbai’s slums show that the average temperature here is six degrees warmer than in the neighbouring housing societies.
We could help to mitigate the situation by pushing the administration to replace the roofs with more environment-friendly material and paint them a reflective white. Clean and green commons could be created in spaces that are currently strewn with garbage.
All in all, it is the approach to climate change that must transform. Urban heat islands and microclimate zones are realities that can no longer be ignored. How we handle them will determine how healthy, clean and green our cities are. Like they say, think global, act local.
The writer is a senior journalist who writes on environmental issues