The city of Hyderabad is bracing for a very hot summer in 2017. According to the Indian Meteorological Department, the 2017 summer in Hyderabad is expected to be even warmer than 2016—the hottest year in recorded history. NRDC, in partnership with the Administrative Staff College of India (ASCI) and the Indian Institute of Public Health, Gandhinagar (IIPHG) is doing something to protect the public from the dangers of extreme heat: deploying cool roofs.
I am writing this blog in this beautiful city in South India, where I am working with colleagues and partners from Hyderabad, Delhi, and Washington, D.C. We are almost ready for lunch after putting the finishing touches on my presentation for this afternoon, and the temperature is already 35C/95F (!) headed for 36/97 under hot cloudless skies. This is the first day of spring; one can only imagine the heat stress that summer will bring (my last trip to India in early May 2016 I experienced a temperature of 46C/116F!).
Communities across India are facing deadly threats from high temperatures. In 2015, a devastating heat wave claimed more than 2,300 lives in India, with a majority of the deaths concentrated in the states of Telangana, Andhra Pradesh and Odisha. The risks increase each year due to global climate change. In addition, rapid urbanization in India’s booming cities is adding to the threat by creating a growing urban heat island effect, increasing the health risk to citizens across the country.
With more frequently occurring extreme temperatures, demand for air conditioning in India is surging, posing a considerable challenge for increasing energy use in the country. Those who can afford air conditioning must spend more on power, and this increased energy use also causes more air pollution for everyone. And the majority of Indians, who lack air conditioning, will suffer more discomfort and increased risk of sickness and death.
Leading cities in India are working with experts on solutions like cool roofs that provide affordable cooling comfort and are energy efficient. Telangana’s Department of Municipal Administration and Urban Development and the Greater Hyderabad Municipal Corporation met with NRDC and partners in Hyderabad this week on designing a cool roofs program for the city.
Cool roofs are white-colored roofs that reduce internal temperatures in buildings. They enhance comfort by reflecting sunlight away from the building. This minimizes heat absorption by the roof. Cool roofs also reduce temperatures by emitting more thermal radiation. This radiation helps to dissipate the solar heat gain and keep the building cooler. By bringing down temperatures inside a building, cool roofs also reduce the need for air conditioning, providing more affordable cooling for those who cannot afford appliances such as air conditioners. They also reduce the load on buildings that do have air conditioning.
Simple options such as lime-based white wash, tarp-like coverings or white ceramic tiles, that are low cost, can help bring roof temperatures down by as much as 30 degrees centigrade and reduce indoor temperatures by 3 to 5 degrees centigrade.
By dropping indoor temperatures for buildings, cool roofs offer multiple benefits for a city. They serve to protect vulnerable groups such as children and elderly from excessive indoor heat, and increase comfort levels for everyone during hot summer days.