Blowing Hot and Hotter: Or Learning to Live With Heat

HEATWAVE alerts were a hot topic this election season despite not being on any political party’s agenda. They competed with election banter and frequently made it to top news listings. Not only were they used as excuses to justify many failed election rallies but they are also being blamed for low voter turnouts.

It can also be argued that heatwaves might have been more of a deciding factor than other kinds of waves in many constituencies by influencing who voted or, more importantly, who did not vote.

Against this subversion of democracy by the sun’s meddling, the Election Commission of India (ECI)’s sole weapon has been stocking electrolytes and water at polling stations, but is that enough?

The last five general elections have taken place during summers with heatwaves endangering the wellbeing of voters. This can easily be fixed by shifting the elections to cooler seasons.

But the adverse impacts of heatwaves on living conditions in the country are much bigger than the elections. In fact, there is overwhelming scientific consensus that heatwaves will keep worsening each year whether elections are held or not.

So what is being done to deal with this apocalyptic dance of the sun?

The media and public tend to confuse heatwaves with climate change. Therefore, the default government response to public outcry is that they are cutting carbon emissions, installing rooftop solar panels, adopting ‘green’ technologies, incentivising electric mobility and so on.

But these measures are needed to keep global temperatures between 1.5°C and 2.5°C above the pre-industrial levels and avert rapid climate change. They are not going to be of much help in stopping heatwaves that have already become a summer fixture or even shelter the public from the sun’s wrath.

In fact, the Intergovernmental Panel on Climate Change (IPCC), Working Group-I, Sixth Assessment Report notes that it is almost certain that the frequency and intensity of heat extremes and duration of heatwaves have increased since 1950 and they will keep increasing even if global warming is stabilised at 1.5°C.

While we are on the subject, it must be noted that it is rapidly becoming clear that the world has missed the 1.5°C bus.

In simpler terms, the climate has already changed enough that these heatwaves have become the new normal. So the question that should now be asked is: What can be done to adapt to heatwaves?

Let us start by first understanding what is happening on the ground.

The unbearable hotness of appearing cool

Summers in India have always been hot. Anyone who has grown up in the plains does not even sweat when the mercury crosses 40°C each summer. In fact, 40°C is considered so normal in the plains that IMD’s criteria for declaring heatwaves is the daily maximum temperature crossing 45°C on two consecutive days.

But today’s 40°C somehow feels much less bearable than the 40°C summers of earlier, even the 1990s. This additional discomfort is fuelled not just by changing climate but equally by changing cityscapes, architecture and lifestyles.

Let us start with lifestyle changes. Traditional local practices that helped people survive the summer have been discarded in favour of ‘cool’ lifestyles copied from elsewhere.

We no longer dress in clothes our ancestors figured out work best for the local climate nor do we eat the foods they painstakingly developed to help our body deal with the heat uptick. For example, we know wear polyester suits instead of cotton kurtas and drink Coke instead of chaach (buttermilk) in places such as Rajasthan.

Further, air conditioning has spoiled our perception of thermal comfort. Any space warmer than 24°C is perceived to be uncomfortable. People no longer like to sweat outside their climate-controlled gyms. The very perception of sweat has changed from a biological response to heat into something dirty to be avoided at all costs.

Certainly, we used to be more mentally and physically accommodating of summer heat in the 1990s than we are today.

Not only have we adopted completely unsuitable lifestyles, but we have also changed the nature of our buildings to satisfy our desire to appear ‘developed’.

No longer do we live and work in structures with two-foot-thick walls made of mud and stone. We look down upon such structures and feel proud to have moved on from them. Even the standard nine-inch-thick brick walls have become rare in modern construction.

These heavy constructions used to soften the impact of the sun, keeping the indoors cooler without heating up the outdoors. Traditional architectural wisdom also used to pack our buildings with many more features such as chhajja (sunshade) and jali (lattice window) that helped keep the occupants naturally comfortable. Today’s paper-thin glossy construction style is more a heat magnet than a shelter from the sun.

Nowadays, indoors get much hotter unless mechanically cooled. The systematic imposition of pucca construction without adopting or adapting traditional passive cooling wisdom and obsession with glass façades has only amplified heat stress.

This change is also reflected in our cities. Big or small, all cities have seen tremendous expansion and concretisation in the last two to three decades. More and more land area is being built upon each year and the population density in existing urban centres is also on the rise.

This increased built-up area and loss of vegetation means more heat is being trapped than being dissipated within the cities. As a result, daytime ambient temperatures inside cities are observed to be 2–5°C higher than their neighbouring rural spaces.

Nighttime temperature differences are found to be even more pronounced. This phenomenon is called the urban heat island effect and is much stronger now than it ever was.

Adding fuel to fire

Moreover, the sun is not the only source of heat in the cities. Millions of cars, buildings and factories are generating tonnes of heat every hour as they burn fuel and consume electricity. This waste heat is mindlessly dumped into the city air in the form of exhaust.

This is air-frying the cities, especially at night. Nowadays, nighttime temperatures in Delhi can remain as high as 35°C during heatwaves.

Yet another heat source is humidity. Indian cities are becoming more humid and the humid season is starting much earlier in the plains than it used to. While the reasons for this are still a meteorological mystery, its impact can already be felt.

The combination of high heat and humidity can compromise the human body’s main cooling mechanism: sweating. The evaporation of sweat from the skin cools our bodies, but higher humidity levels limit this natural cooling. As a result, people can suffer heat stress and illness, and the consequences can be fatal, even at much lower ambient temperatures.

To sum up, the weather station temperature observation might read 40°C but people are exposed to much more heat and are much less able to handle the heat. This pincer movement of increasing exposure and decreasing adaptability is totally unaccounted for in our official heat action planning, which is concerning.

Can the fire burn down the stove itself?

Climate scientists are clear about the increase in frequency and duration of heatwaves, but the current understanding of their long-term impacts is limited. Especially understudied is the impact these heatwaves will have on various infrastructure systems in the Indian context.

For instance, it is well known that surface water availability reduces in the summer. But during heatwaves, not only does surface water become even more scarce, it becomes much hotter as well. This has serious implications on not just drinking and sanitation water infrastructure but also on electricity generation, which is a critical element of all cooling solutions devised by governments.

The magnitude and cascading impact of this threat has not yet been computed in India or anywhere else, but there are ample lived experiences to fall back upon. Let us look at electricity to get an idea.

Studies show that higher air temperatures reduce fuel burning efficiency— high temperature causes lower atmospheric pressure which in turn lowers oxygen concentration that is needed for combustion. This affects the efficiency of turbines, boilers and gensets.

Therefore, all fossil fuel-based energy generation plants suffer a drop in the efficiency of their turbines and boilers when the difference between ambient temperature and combustion temperature decreases during a heatwave. Even geothermal-based power plants suffer similarly.

For nuclear power plants, power output can decrease by more than 2 percent per 1°C rise in ambient air temperature due to physical constraints it puts on the cooling systems.

Heatwaves can also affect the generation capacity of hydroelectric and solar energy systems.

Hydropower generation may be decreased due to increased evaporation from water bodies which leads to lower availability of water to generate power. This effect may be amplified during a dry season or where water levels are otherwise low.

Photovoltaic generation capacity starts to fall as ambient temperatures rise above 25°C. European studies have found that for every 1°C rise in temperature, the efficiency of solar cells drops by 0.4 to 0.5 percent in relative terms.

Heatwaves do not only warm up the air. Higher water temperatures create cooling constraints and affect electricity generation from all sources— fossil fuels, geothermal, biomass and nuclear power.

All thermal power plants need an enormous volume of water to function. They withdraw this from nearby water bodies and return it back to them usually at higher temperatures. If the temperature of the water in the water bodies is higher than a certain threshold, then the water cannot be used for cooling purposes in the power plant. Therefore, electricity produced per unit of fuel consumed is lowered if high-temperature conditions persist.

In nuclear power plants, it is estimated that there is a 1 percent efficiency loss for every 5°C rise in water temperature. For instance, during the 2003 European heatwave, temperature in rivers rose so much that France had to lower its electricity generating capacity by 4,000 megawatts, the equivalent of four nuclear power stations. Even last summer during the heatwaves, French nuclear plants had to cut generation as river water got too hot to use.

Melting grids

Grid systems obtain high-voltage electricity from power plants and transmit it to neighbouring, distant or cross-border substations, where the voltage is methodically lowered for distribution to customers.

In India, the transmission and distribution of electricity are done mainly by overhead systems. Therefore, high ambient temperatures can have large adverse impacts. Transmission and distribution losses are currently estimated to increase at 1 percent for every 3 °C rise in temperature.

Heat can also impact the distribution transformers. If a power plant fails, there are alternative solutions to cover the demand, but alternative grid routes are not usually available.

For instance, during the 2006 California heat wave 1,150 distribution line transformers failed to cool down and stopped operating, leaving about a million people without power.

Similarly, in India, during the heatwave of 2012, the breakdown of a series of distribution transformers plunged more than half of the country into darkness for multiple days. This blackout was partly due to the direct impact of heat on the transformers and partly due to heatwave-induced increased demand that was 9 percent higher than supply.

Selling electricity like hot cakes

According to the Grid Controller of India, at temperatures above 30°C aggregate, electricity demand in India increases by 11 percent or more compared to temperatures of 21–24°C. This demand is primarily fuelled by the cooling needs of the people and partly by the water pumping needs of parched farmlands.

An increasing number of households and offices are adopting air-conditioning as their primary mode for space cooling, which is the most energy-intensive means of cooling. Electricity demand tends to increase rapidly from the third and fourth days of consecutive hot days, as air conditioners increase output to manage the accumulating heat in buildings.

According to the Bureau of Energy Efficiency (BEE), about 60 percent of the peak electricity demand in cities during heatwaves can be attributed to air conditioning.

Since cities and buildings are not cooling down even after sunset, thanks to waste heat and heat-trapping architecture, people are actively using air conditioning at night to enable sound sleep.

It has been observed in Delhi and other metros that peak energy demand shifts to midnight during summers and specifically during heatwaves. This trend is problematic as it undermines efforts to use solar energy, especially rooftop solar systems, to meet domestic electricity needs during summer.

Differential heat treatment

It must be noted that even though a relatively small proportion of the urban population (about 5–10 percent of households) currently owns air conditioners, they manage to dominate the peak electricity demand. Therefore, this is also an equity challenge in India.

Further, the waste heat from domestic air conditioning, which is generally dumped in the balcony or back alley, is also altering the micro-climate of cities by thermally polluting spaces that would otherwise have naturally cooled down after sunset.

This thermal pollution directly affects the poor as hot exhaust from posh neighbourhoods has replaced the cool night breeze on their roofs and windows.

Moreover, due to their relative powerlessness in India’s democratic setup, poor neighbourhoods are subject to more frequent power outages as part of the state’s resource rationing. Therefore, they are unable to use ACs even if they manage to install them in their homes.

The infernal feedback loop

Heat stress is a cyclic problem. Heatwaves fuel demand for air conditioning, which in turn further heats up the planet in general (carbon emissions for electricity generation) and urban neighbourhoods in particular (urban heat islands and waste heat from human activities).

A European study found that waste heat generated by a city’s worth of air conditioners during a heatwave can by itself raise the outdoor temperature by more than 2°C.

To make things even more complicated, heatwaves also impede our ability to generate and distribute electricity, introducing equity and resource management challenges.

The cascading impact of the aforementioned realities will be disastrous in multiple ways. The sheer scale of energy demand combined with the stunting of electricity generation and supply during summer can lead to serious energy and public health crises at regional and global levels.

Studies have shown that heatwave-induced blackouts are becoming increasingly frequent and these tend to amplify mortality and morbidity risk for the public. Under blackout conditions, indoor heat exposures rise, particularly dangerous for individuals who would otherwise have access to air conditioning.

The insignificance of lukewarm policies

It is a major challenge to find solutions that help build systems for cities and citizens to adapt to this new reality. Current policies are sadly nowhere close to addressing this fire-breathing monster. 

On the energy supply side, the Union government does not have any climate resiliency plan for its electricity sector. The Central Electricity Authority covers heatwaves under its Disaster Management Plan for the Power Sector, but only to the extent of advising distribution companies to make provisions for additional peak demand. It does not say anything substantive on the challenges or strategy for generating and distributing electricity during a heatwave.

On the demand side, the policy focus has remained limited to reducing the cost of energy-efficient air conditioners, ignoring the fact that the commutative load of these will gobble up the limited electricity supply to the detriment of several other sectors while making the outdoors even hotter.

On the public health front, almost all state governments have made Heat Action Plans (HAPs) in the last few years. These Graded Response Action Plan (GRAP)-style warnings and emergency response plans are more fluff than concrete. The most potent action listed in these plans is to increase the public availability of electrolytes and drinking water during a heatwave.

HAPs are also totally blank on how to build infrastructure so that cities and homes do not heat up beyond the ambient temperature. Some plans do talk about increasing green cover as their long-term strategy but without dwelling on the kind of greenery needed to shield from the heat. The current practice of chopping down dense tree covers in city centres and then compensating for them by planting palm trees and grass lawns in remote suburban parks will not make cities heat-resilient.

The fatal problem with HAPs is that they apply the strategy of dealing with smog (which is not very successful to start with) to heatwaves. Heat is fundamentally different from air pollution; we cannot shut down its major source as we can do with air pollution. Like Frankenstein’s monster, we have caused it but have no control over it.

How to adapt to the heat— building resilience

The impacts of heatwaves are complex, compounding and cascading in nature. Heatwaves limit availability while increasing demand for critical resources such as water and electricity that can exacerbate the deficit to the point of system failure. There is an urgent need for a cross-sector policy to ensure India can continue to function without a meltdown or blackout in the future.

For instance, the electricity issue as discussed above makes it evident that just adding more capacity— dirty or clean— won’t do as heatwaves can short-circuit the whole grid by melting the distribution lines and changing demand patterns. Heat-proofing generation and transmission will be an engineering challenge while heat-proofing distribution and demand will be a social and political justice challenge.

Who will get priority over electricity and for what? Will it be the farmers of Punjab who need to pump out groundwater for their parched fields or the consultants in Delhi who need to air condition their gyms or a family in rural Andhra Pradesh who needs to run their ceiling fan to avoid a heat stroke? Will the priority be decided through free market mechanisms or based on the demands of natural justice?

Similar complications need to be addressed in heat-proofing water supply, agriculture and every other sector. This will also require resource balancing among sectors. For instance, water is critical for drinking, sanitation, electricity generation, irrigation and industry but during heatwaves its availability becomes severely limited. The policy must figure out a fair compromise among these competing thirsts.

Yet another task for policymakers will be to ensure that the unavoidable 40°C ambient air does not feel like 50°C or more. This will require redesigning our cities and buildings so that they do not trap heat unnecessarily.

That will require increasing and integrating green and blue cover in our urban mosaic in a way that every neighbourhood (rich or poor, downtown or suburban) gets a reasonable chunk of them. This can only be done by rejigging long-term city master plans and altering building byelaws. In fact, the criteria and priorities of master planning will need to be entirely reconsidered to include impact of heatwaves.

Further, there is a need for finding ways to reduce waste heat generated in cities and devising systems to manage the unavoidable exhaust. A large part of this will be achieved through technological transformation but that would have to be supported by larger behavioural changes and reprogramming of societal perceptions and aspirations of thermal comfort. 

Learning to live with the fire-breathing monster 

Most importantly, extreme heat is a threat to public health and wellbeing. The human body cannot function optimally once the outdoor temperature crosses 35°C, while extended exposure to temperatures over 40°C can be fatal. But long afternoon siestas of yesteryears, which provided much-needed respite to the human body in extreme conditions, are now frowned upon in the current work culture.

Now that the nights are also too warm to sleep, recovery from daytime heat exhaustion is getting expensive for the rich and increasingly impossible for the poor. While the rich can still continue to work in air-conditioned spaces (given they do not trigger a blackout), health risks are especially grave for most of those working outdoors or in factories without cooling.

Heatproofing here will have to mean redoing the labour laws and ensuring their rights are honoured (no 70-hour work weeks!).

In conclusion, there is not going to be any magical quick fix for this problem. Cutting carbon emissions to stabilise climate change is great but on its own it is not going to help survive the wrath of the sun. To survive the coming summers a lot more needs to change. 

This is going to be a really long and difficult road that will require extensive rethinking of our entire value system and redesigning of the entire infrastructure ecosystem. It is a multiple-election cycle policy agenda and should not be treated as just an inconvenience for electioneering.

There is no escaping from this heat anymore. We have to learn to live with it. And the learning has to start now. 

Avikal Somvanshi is an urbanist and data scientist whose recent work examines the energy consumption patterns in cities to decode links with climate change.

 Courtesy: The Leaflet