A Lot More Trees, Water Bodies Needed To Counter Urban Heat Island Effect in Ahmedabad

However, afforestation drives over the last 10 years have led to a substantial increase in Ahmedabad's tree cover. But the added trees alone can't protect the city and its inhabitants from the effects of the Urban Heat Island (UHI) effect, a fact that was discussed in the first part of this two-part series.

Planting more trees has been the traditional method to combat rising heat in India's cities. But as mentioned in the first part of the story, buildings and surface concrete that absorb heat during the day release it at night. This keeps the temperatures almost the same round the clock, preventing the surrounding trees and vegetation from cooling the area at night. 

While Gujarat is bearing the brunt of heavy rainfall right now, a few months ago the state was ravaged by a heat wave that impacted daily life. Heat Action Plans (HAPs) are put into action for such conditions and list what the governments at the state, district and city level need to do. 

An assessment report of the Centre for Policy Research (CPR) on HAPs noted that one of these plans' most important functions is to direct scarce healthcare, financial, information, and infrastructural resources to the most vulnerables facing extreme heat in their jurisdictions.

Life In Cramped, Heat-Trapping Conditions 

When the vulnerables are properly identified and categorised, it is easier to bring out actionable solutions. Pavement and slum-dwellers have a much harder time coping with UHI and land surface temperature, according to a 2020 report by the National Institute of Urban Affairs (NIUA). 

This is because, the report adds, not only are these localities cramped, but are also built with heat-trapping materials.   

These materials may be uninsulated metal or asbestos roofs, thatched roofs, bamboo, mud and plastic - which, in most of the cases, can aggravate heat impact. 

The way out for these habitations is the utilisation of funding, such as in-situ Smart City Mission schemes, to build cool-roofing of low-income households. Also, these cool-roofing structures can be surrounded by open and green spaces.

Such efforts have been highly effective in bringing down indoor temperatures. 

Open Spaces, Water Bodies

Maintaining open spaces and preserving cultivable lands can result in better ground-water recharge and reduce flooding of concretised areas. 

Ahmedabad has seen 12 per cent growth in tree cover through many afforestation drives. However the city itself is predicted to grow only slightly from "227 square km in 2019 to 234 square km in 2030," according to the report of IIT Roorkee and School of Technology, PDEU's joint spatio-temporal study.

"Green infrastructure, increasing urban greenery, such as parks, green roofs, and street trees, can help lower temperatures by providing shade and cooling through evapotranspiration," said Chirag Shah, Head of the Department of Environmental Science, and Coordinator, Government Science College.

The IIT Roorkee-PDEU study notes that Heat Action Plans don't take into account many nature-based interventions. 

The interventions can be short and long-term measures like enhancing green cover, maintaining water bodies, reducing water wastage and increasing open spaces. Natural or man-made reservoirs in Ahmedabad have either dried up (for example, the Sarkhej Roza Lake) or are close to drying up. 

One measure of green roofing, also known as cool roofing, has been carried out where white lime wash has been applied to the roofs of 3,000 low-income homes. But still, it has only covered 2 per cent of the city’s low-income households.

Dr Janki Shah, Programme Director, Sustainable Lifestyle and Traditions, Centre for Environment Education (CEE), Ahmedabad, spoke to The Secretariat on the importance of open public spaces and replenished water bodies. 

"Nature-based solutions such as green and blue infrastructure also play a critical role in fighting rising temperatures in urban areas. Blue infrastructure can include the revival of urban local water bodies such as ponds and lakes. Increasing tree cover can play an important role in temperature control while also helping in mitigation measures through carbon sequestration (or carbon capture)." she said. 

The Cost Factor And Funding

The buzz surrounding Ahmedabad's becoming a global city or smart city has led to rampant privatisation and commodification of public assets, which are limited in numbers and potential.

CPR's assessment report on HAPs notes with concern that only 11 of the 37 HAPs in the country have a clear funding mechanism in place, and sadly Ahmedabad is not one of them. 

With economic growth continuing to attract migration to urban areas, people will continue to flock to Ahmedabad and other cities for whatever work they can find. 

In pursuit of their place in the sun, migrants will continue to suffer extreme heat or floods, live without a proper water source, and find homes in burgeoning ramshackle slum tenements, unless and until the state steps in to bring forth measures including nature-based interventions that help give their lives more comforts and dignity.