Over the last 28 years, Anshu has worked extensively on disaster risk and climate emergency issues. He has served as an advisor and consultant to numerous Governments, corporate, non-profit, UN and funding agencies. He is also a global tutor for Oxford Brookes University.

The world is heating up like never before. According to NOAA's 2023 climate report, the combined land and ocean temperature has increased at an average rate of 0.11° Fahrenheit (0.06° Celsius) per decade since 1850, or about 2° F in total. The rate of warming since 1982 is more than three times as fast: 0.36° F (0.20° C) per decade.

The India Meteorological Department’s (IMD) summer outlook for this year indicates that the entire peninsula will see temperatures well above normal. While this is alarming in itself, all Himalayan mountain states will see abnormal heat. When the Himalayas are sick, the rest of the country cannot remain healthy.

This rising temperature raises livability risks and is certain to have cascading environmental impacts. These impacts may be visible soon in the form of extensive cloud bursts, glacial lake outbursts, flash floods and landslides. Creeping impacts of water and heat stress on crops will have a deep economic impact on livelihood, commodity prices and trade.

Heat is more than just maximum temperature
The IMD’s summer outlook specifically informs us that minimum temperatures will be higher than normal. This will result in no respite from the heat during the nights, a phenomenon that leads to a spike in heat deaths – most of which are on the hottest nights rather than the hottest days. Another forecast for the summer of 2024 is longer heatwave durations, which has risen from an average of 8-10 days to nearly 20 days this year.

This leads us to discourse on the impact of heat on the human body. All natural ecosystems need respite after exposure to heat. Longer heatwaves deny us this respite. Despite accounting for climate action being taken, projections forewarn of heatwave durations that may extend upto 50 days in the 2041-2070 period, with peak temperatures exceeding 50º C. This may sound like the distant future to some, but it is when today’s primary school children will be in their prime, trying to build families. Unfortunately, we may leave them cities that are unlivable.

As we move from the hot dry months to the humid ones, heat takes on a hazardous form. The heat index recently introduced by the IMD indicates that a 49º C temperature with 10% relative humidity is less dangerous to human health than a 35º C temperature with 80% relative humidity. Few realize that it is unsafe to assume that a reduced temperature of 35º C signals the end of heat-induced health impacts. In this condition, the body is unable to cool itself and starts getting impacted in its own heat.

Cooler cities & neighborhoods are the future, with a requirement for strategic actions to treat small pockets as local climatic zones and keep them safe and cool

Many of us keep an eye only on maximum temperatures as an indicator of heat; the duration of heatwaves, night temperature and humidity are also critical factors that significantly exacerbate the impact of heat on human health and livelihoods.

Making the impacts of heat visible
Traditionally, extreme heat conversations were centered around heatstroke, which can be fatal. However, these cases are very difficult to identify. Most heat deaths are reported as cardiac arrests or other, easier-to-establish final outcomes, like dysentery. More widespread than heatstroke is heat stress, which, although less severe, also makes people feel unwell and reduces their productivity.

Elevated blood pressure, headaches, nausea, burning eyes, and sleep disruption are some symptoms that are common but go unnoticed and untreated. Anger, mental health and pregnancy outcomes all have convincing indications of a correlation with extreme heat, however, these are nascent areas of research. Heat stress thus inhibits one from working or studying efficiently and leading a normal, healthy life.

Heat doesn’t walk alone
Urban fires see a spike in the dry heat season – the triggers range from electrical short circuits on overloaded power infrastructure to dry combustible material fanned by hot winds. Wildfires ignite in the tens of thousands and spread across wide swaths of land, burning for months till the rains douse them. They destroy biodiversity, create air pollution, and contribute to emissions that only make matters worse.

As heat leads to increased water demands, supplies are at their lowest, both from surface and ground water. Lower water supply also usually translates to higher water pollution concentrations, and thus additional adverse health impacts. Finally, and surprisingly, extreme heat makes soil hydrophobic - a phenomenon where it does not absorb as much water as moist soil would – leading to greater runoff and floods when it rains suddenly after a period of extreme heat.

Heat is part of a much larger story. It is not an isolated weather event.

Make or break: how we build
The story gets murkier with us humans in the picture. We have created heat islands with the way we built our cities, the vast expanses of concrete and glass replacing soft soil surfaces, water bodies and green spaces. Not only are cities hotter than the countryside, but dense, low-income urban settlements are also significantly hotter than the rest of the city. The same applied to extensively built-up areas, such as roads, pavements, and parking lots.

At the micro level, prevalent building materials and designs keep people hot round-the-clock, as buildings accumulate heat during the day and can’t release it sufficiently during the night.

Have you ever felt a blast of heat while opening the door of a car parked in the sun for a few hours? You are often entering a space that is above 65º C in temperature. In the hurry of our hectic lifestyles, many of us nowadays don’t have the time or patience to open the doors and let the hot air escape. When we jump in trusting that the air conditioner will make the car cooler in a couple of minutes, we are pushing our body to its limits. For some of us this is a choice, but for those living in tin shacks in slums, it is a reality. Indoor temperatures regularly exceed 45º C even as the city reports a high of 38º C. housing, this becomes a reason to turn the air conditioning to its maximum, in turn consuming more energy, emitting more carbon, and expediting the heating of the planet.

It’s time to anticipate, adapt and be cool
A multi-pronged approach is needed to learn to live with heat. And learn we must, as we have no other choice. The first step is to sharpen our ability to anticipate. Improved forecasting capabilities are at work with the IMD warning us of what lies ahead. It is upon us to translate this into what heat will mean to us in our homes, workplaces, educational facilities, activity spaces and commutes. Anticipation can successfully inform action to be timely and appropriate.

We must equally improve our capacity to absorb the impact of heat, and indeed try and thrive despite it. Cooling strategies, tools and actions are going to be key for this. Cooler cities and neighborhoods are the future, with a requirement for strategic actions to treat small pockets as local climatic zones and keep them safe and cool. Cooler buildings using solar passive materials and designs that harness the insulating capacities of walls and roofs, shading, water, and vegetation will be as important as innovating cooling devices that run on renewable energy and cool people without heating the planet.

Last but certainly not least, technology will be a valuable weapon in this fight. High-resolution, real-time geospatial data and ground-truthed built-environment intelligence, along with Artificial Intelligence models to identify hyper-local heat impact of an individual buildings, helps in identification of the high heat risk hotspots in less than three hours. Automated early impact systems providing heat impact warnings and advisories to families of impending risk are all realities today that are available and affordable for immediate deployment.

It is going to be incredibly hot. We must act with credible information. We have no time to rest.