Cooling cities amidst the scorching heat

In India climate change is staring us in the face this summer. Its current manifestation is the blistering heat in huge swathes of the country, particularly in the north. The soaring temperatures, categorised as an intense heatwave, are predicted to worsen in the coming months. Climate scientists warn of acute conditions in the northern states, with temperatures in New Delhi likely to touch 44-45 degrees Celsius, while parts of northern Indian could reach a scorching 46 degrees C.

The Indian Meteorological Department (IMD) declares a heatwave when temperatures cross 40 degrees C in the plains, 37 degrees C in coastal areas and 30 degrees C in the hills. This year temperatures have been unprecedentedly high since March — declared the hottest in 122 years. According to climate scientists, the high temperatures can be directly attributed to the accumulation of greenhouse gases in the atmosphere.

Given that heatwaves are going to be frequent and intense, what can be done to prepare the larger populace for it? Many long-term answers have been detailed in ‘Beating the heat: A sustainable cooling handbook for cities’, brought out by the United Nations Environment Programme (UNEP) and valid for 2022. It has case studies and city examples, providing administrators inputs for a host of community-centric interventions.

Community cooled amenity

These are interventions that will make a difference even to those who cannot afford the cooling solutions available to the well-to-do and commercial establishments. The report highlights low-cost examples of public cooling infrastructure such as community cooling centres, cooled transit stations and public water features that can impact large populations. But for this, the administrations at all levels — local, state, and national — need to have the will.

The handbook has a few good examples from India, which ran pilots of the cool roof project in Ahmedabad and Hyderabad for low-income housing some years ago. It also trained and educated the community to instal cool roofs coated with heat-reflective paint or three layers of lime. This practice does reduce indoor temperatures. Anjali Jaiswal of the US-based Natural Resources Defence Council, which monitored the Ahmedabad project, has been quoted as saying that the temperature comes down 2-5 degrees C when compared with traditional roofing. It also costs as little as ₹1.50 per square foot. But pilot projects alone won’t do. They need to be replicated in every town and city.

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The UNEP handbook recommends drawing up ‘heat action plans’ that incorporate comprehensive early warning systems and preparedness combined with the objectives of public awareness and community outreach; inter-agency coordination; capacity building among healthcare professionals; and ways of reducing heat exposure and promoting adaptive measures.

The Natural Resources Defence Council (NRDC) and Public Health Foundation of India-Indian Institute of Public Health-Gandhinagar (PHFI-IIPH-G), along with other key stakeholders have been involved in developing and implementing heat action plans in different cities. But the scale needs to be increased as fast as possible. Heat action plans need a lot of coordination across government departments and the requisite funding. These need to be put in place.

Nature-based response

The typical urban response to rising temperatures is air-conditioning, which only adds to emissions and is not a sustainable solution. The handbook advocates design and planning that is both nature-based and infrastructure-related to achieve what is referred to as ‘human thermal comfort’. This involves mandating that all buildings go in for energy-efficient design, low-emission cooling technologies and sustainable refrigerant-use approaches. These together would help in lowering climate impact.

And now, amidst the current heat, a new analysis by Dr Mariam Zachariah and Dr Friederike Otto of the Imperial College London, put out by Climate Trends, directly points to human activities like burning coal and other fossil fuels as the cause of intense heatwaves. Notes Dr Zachariah: “Before human activities increased global temperatures, we would have seen the heat that hit India earlier this month around once in 50 years. But now it is a much more common event — we can expect such high temperatures about once in every four years.” This warning has been reiterated by health experts saying extreme heat so early in the year is particularly dangerous.

Though the National Disaster Management Authority and IMD have been working with 23 states with high temperatures to help them develop heat action plans, it is not going to be easy to mitigate such extreme heat events. But local interventions for sustainable urban cooling, along with programmes to raise awareness, build capacity and find financing solutions would have the most positive impact on a city, town or state. It would, of course, also add to the national and global efforts to mitigate climate change.