Just like changing seasons, we follow discussions and news cycles that run along the ongoing seasons. So, summer-time topic of excessive temperatures and heat stress will give way to air pollution in a few months’ time in Delhi-NCR. Presently it is the time to dwell upon cities’ heat action plans and the associated remedial measures, all very relevant and much needed. However, generally a vital piece of good urban planning gets a short shrift. And that pertains to creating green and blue spaces to keep the temperatures of a city naturally cool. The modern architecture and urban planning results in Urban Heat Island (UHI) effect where urban areas experience significantly higher temperatures. Essentially, the city development alters the natural landscape, replacing cooling elements with heat-absorbing elements. Materials like asphalt, concrete, and dark roofs absorb and retain massive amounts of solar radiation rather than reflecting it back. Compounding that, removing trees and grass eliminates natural cooling. So, on one hand our modern cities imbibe all those design features that end up the increasing ambient temperatures, on the other hand it also eliminates the natural cooling mechanisms.
Therefore, many countries are studying closely how to control urban heat islands phenomenon to keep the temperature of cities lower. Under the LUSH (Landscaping for Urban Spaces and High-Rises) framework, developers in Singapore are legally obligated to replace ground-level greenery lost to construction with vertical green walls and high-altitude sky terraces. This dense vertical foliage blocks concrete facades from acting as heat absorbers during the day and radiators in night. Kuala Lumpur is planting continuous ecological green corridors along defunct railway tracks and highways. In Medellín, Colombia, the city created a network of 30 green corridors by planting thousands of trees along roads and waterways. This initiative is said to have reduced local temperatures by up to 20C. Going a step further, an elevated highway was dismantled in Seoul to restore the Cheonggyecheon Stream and converting it into a 10 km long public park. This blue-green corridor has reportedly lowered nearby summer temperatures by 3.3°C to 5.9°C. The city of Melbourne is working to increase its green cover from 22 per cent to 40 per cent by the year 2040 as part of the long-term plan to fight the heat. In addition, to meet water requirement of the trees, it integrates its forestry goals with storm-water catchment infrastructure, funneling street runoff directly into underground soil beds.
Thus, there are a number of strategically important elements that can be integrated at the planning stage itself to yield long-term cooling of the cities as a whole. These ranges from `Pocket Parks’, small urban green patches tucked between buildings to provide localized cooling and shade to immediate neighborhoods to densely planted urban forests; from vertical green walls to linear green corridors. The blue infrastructure may include rejuvenated wetlands and ponds situated within the expanding cities. Gurgaon itself said to have 181 urban ponds and 75 large wetlands, which can be scientifically rejuvenated for the purpose. Indeed, an image captured by NASA ECOSTRESS (Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station) in May, 2022 covering the urban conglomeration of Delhi clearly highlighted the effects of urban heat islands and greenery, with New Delhi at 39°C and rural fields nearby at 15°C. Even within New Delhi, temperatures around India Gate surrounded by leafy vegetation could be as much as 12°C lower compared to its surrounding paved neighborhoods.
The 2020 report of The Lancet `Countdown on health and climate change: responding to converging crises’ identifies India as one of the worst affected countries of climate change induced heatwaves facing potentially huge economic loss. As a mitigation measure it lists out urban green spaces to reduce population exposure to heat. As opposed to other interventions requiring large investments and technological solutions, the climate-adaptive urban planning is not capital-intensive. What is required, however, is to move from after-thought band-aid measures to local climate based holistic urban planning framework and their implementation in right earnest.
Disclaimer
Views expressed above are the author’s own.
