The last three years were the hottest ever recorded and it’s only going to get worse – to the point where people will start to die from overheating. Unless you have an air conditioner. 

As a species, humans can only tolerate so much heat. Anyone caught outside in the so-called wet-bulb conditions – 35°C with 100% humidity for more than six hours – will perish. The body become unable to cool itself and shuts down. When summer temperatures eventually reach this point in the decades to come, people will need an aircon unit to stay alive in the same way as an astronaut needs a spacesuit.  In the meantime, mere heat-stress mortality is already on the rise. 

Real life studies show the optimum temperature for humanity is somewhere between 17°C and 27°C, but the earths climate is starting to move outside the band that will support human life. There are several factors going into this calculation: the optimum in London is 18°C where air conditioners are uncommon, whereas the same in Texas is 27°C where the use air conditioners is widespread. Even as temperatures move beyond what we can survive, technology will come to humanity’s rescue. For a while anyway.

In cold countries, heating is considered a necessity and often provided by the state. That is not true in hot countries. As out-of-bounds temperatures start to appear, governments around the world will have to start to factor heat-deaths into social policy and urban planning.

Wet-bulb conditions already occur in places like Pakistan and UAE, but they have been short-lived, a few hours only. Scientist say that as the Climate Crisis accelerates extreme heat is already becoming a problem even before wet-bulb conditions are common. As IntelliNews reported, mortality is already rising simply due to heat-stress that singles out the old and infirm. Most heat-deaths occur in people older than 65 at a lower levels of heat and humidity. A recent study projects that by 2050, several lower-income countries could see heat-stress mortality overtake some of the major lethal diseases as the leading cause of death.

Air conditioners

The solution is the mundane air conditioner. Already considered essential in developed countries with hot summers, air conditioners are going to become existential in the countries most exposed to extreme temperatures. Access to air conditioning will literally save lives.

That is a problem for the poorest countries. In large parts of Africa electricity consumption is so low that even running a single-room air conditioner for an hour exceeds the average person’s entire daily household power use.

In richer hot countries in the Middle East power is still an issue and as aircon units use a lot of power. Government need to plan for very large increases in power to cool everything from homes to factories as summer temperatures in places like Oman will regularly exceed 50°C in the hottest months. In a recent study, McKinsey estimated that “cooling” will consume 40% of the cost of adapting to the new hot climate in the period 2020-2050, with the need for this spending to become acute from about 2035 onwards as power consumption will start to rise exponentially form then on.

A typical aircon unit consumes about 1,000 watt-hours of electricity per hour. Less efficient models can require 1,500 watt-hours making energy efficiency critical in countries where every kilowatt counts. In at least 45 countries, the average residential electricity use per person for a full day is lower than the electricity needed to power an air conditioner for one hour, according to a report from Our World in Data (OWID).

The problems in Asia are similar, although the population has better access to electricity, but the power budgets still don’t stretch to keeping a family cool all day. In India, the average daily household electricity budget allows for just 44 minutes of air conditioning. In Nigeria, it is 13 minutes. In South Sudan, only four minutes. And that assumes the houses are hooked up to the grid.

The penetration of aircon units remains extremely low. Only 5% of households in India have air conditioning, compared with 6% in South Africa and 16% in Brazil, according to the International Energy Agency (IEA). In the very poorest countries, many of which are the most exposed to heatwaves,  penetration is close to zero.

Even the penetration of electric fans, the cheapest and most basic alternative to aircon, is low. A simple fan uses roughly 50 watt-hours per hour, but that still only gives an average Nigerian four hours of cooling a day, assuming they don’t turn the lights or TV on.

Cooler countries will see temperature-related deaths fall

Even developed cooler countries in the Global North are going to come under pressure. Ironically, initially the number of heat-related deaths will fall as temperatures rise, as extreme cold still kills more people in the developed hemisphere than heat, according to the Global Burden of Disease study.

The study that estimates that 7.7% of deaths were attributed to temperature found that 7.3% were from cold temperatures; 0.4% were from heat. Globally, cold deaths are nine-times higher than heat-related ones. In no region is this ratio less than three, and in many, it’s over ten-times higher. Cold is more deadly than heat, even in the hottest parts of the world.

Another study published in Nature Climate Change in 2021 attributed one-third of heat-related deaths across all countries to climate change and that cold-related deaths are falling every year.

But that is not going to stop the problem transition from cold-related deaths to heat in the coming years. There have been several blisteringly hot summers during the annual disaster season which got underway three years ago. Extreme heatwaves are regularly hitting the south of Europe and US southwest, where temperatures have broached 40°C as earlier as April. A heatwave last summer in Europe, caused an estimated 16,000 excess deaths.

Aircon units are widespread in the US; now they are starting to appear in Europe. The sale of aircon units in Europe peaked at around 10mn in 2022, during an exceptionally hot summer, but are expected to continue to rise going forward. But sometime after 2035 they will have to become mandatory in all buildings in the worst affected countries.

The increased demand for power will add to the cost-of-living crisis in the Global North. Although down from their 2022 peak, consumer prices remain well above pre crisis levels and rising power costs are already make things worse, according to the IEA’s last Household Energy Affordability report. In Europe, after the 2022 energy shock, power prices remain twice their long-term pre-Ukraine war average and now they are rising again thanks to the Iran war.