Cool it
Illustration: Yogendra Anand / CSE

Cool it

We need ways to reduce the need for cooling devices. This means we need to build with nature, not against it

This year, when Delhi touched record temperatures of close to 50°C, I experienced first-hand what it would be like to live in extreme heat. It was an inferno; the proverbial hell. There was news of forest fires; of buildings going up in flames; of electrical equipment burning. This is the first time I have seen leaves on trees being burnt to a crisp. This is not what we should wish our future to be.

Even as I write this, I am aware that I am privileged; I am comforted by electricity that runs appliances to cool me. I am not exposed to the deadly harm that millions in my country endure each day. They are exposed to the scorching sun; they do not have access to cooling devices; they see their land bake; their water dry up; their forest on fire. They are the true victims of climate change. The irony is that they are not responsible for the greenhouse gas emissions that have caused the planet to heat up. The irony is also that the electricity that cools me and many others, will contribute to the stock of emissions and force the planet to further heat up. Unless, of course, we transform our energy systems to make them low-carbon and clean. So what do we do?

There is no doubt that we need to do much more to combat climate change so that we can contain the rising temperatures. But frankly, we also have to find ways to cope and to live with this heat. This is what I want to discuss.

First, let’s accept that the heat is here to stay and will only get worse. Second, let’s understand how much heat humans can tolerate. Scientists believe that this range is 40-50°C. But it depends on how temperature-acclimatised our bodies are; on whether the heat is dry or wet—accompanied by high levels of moisture in the air, which makes it more unbearable; and, of course, on the conditions in which we live.

This last factor can be controlled, and must be focussed upon in the heat management agenda. This requires, firstly, looking at what would reduce the impact of heat in the lived environment. Data shows that the heat island effect is intense in areas that have high concrete and human density and low vegetation and waterbodies. In fact, temperature trends show that big Indian cities with high concretisation are not even cooling down during the night—this then adds to the heat impacts. My colleagues point out that the rise in night-time minimum temperature is worse for human health. So, it is clear that we need a new generation of city planning, where we can maximise the cooling gains brought by green and blue cover.

But this is easier said than done, particularly in mega cities where land is already concretised and under pressure for more high-rise development. Therefore, we also need abatement measures in our buildings for thermal comfort. You could argue that this means putting air conditioner-type devices in every house, every room. But this is short-sighted—cooling devices not only add to the cost of energy but also drive up emissions because of energy usage. The use of air conditioners also leads to more heat being trapped, more increase in night temperatures and more human distress.

So, we need ways to reduce the need for cooling devices—this means we undertake construction so that we can build with nature and not against it. This is today called passive architecture. In the past, this just meant that people used their knowledge to build smart. Traditional houses incorporated all the principles of providing shade from direct sunlight and ensuring ventilation. In fact, thermal comfort is about how much the skin on our bodies can breathe; it means cooling with ventilation. In simple words, building closed rooms, with double-glazed windows and even highly efficient air cooling systems, is not as good as buildings with insulated materials, windows, fans and then the additional air conditioner. This is the traditional building science that modern architects must learn in our climate-risked and hot times. We must also relearn the science of wind-flows and incorporate it in the design of our building layouts; this is never done; never even considered.

Having said that, let me be clear that no amount of adaptation will work without drastic measures to cut greenhouse gases. This is not happening; not at the scale or pace needed. Today, Europe is faced with a backlash against its action to combat climate change; the US is not yet on track to meet its target to cut emissions by 50-52 per cent by 2030. I could go on. But the fact is that this extraordinary Indian summer should be a warning for the world that the heat is on; the world is on a boil and all this will only get worse, not just in India but across the world.

Down To Earth