Someday, he said to himself, it’ll be so hot that nothing will keep this place from melting; he recalled the day his l-p record collection had fused together in a lump, back around ’04, due to a momentary failure of the building’s cooling network  … And at the same moment every parakeet and Venusian ming bird in the building had dropped dead. And his neighbor’s turtle had been boiled dry … The wives, however, had huddled at the lowest subsurface level, thinking (he remembered Emily telling him this) that the fatal moment had at last arrived. And not a century from now, but now.

Philip K Dick, The Three Stigmata of Palmer Eldritch (1964)

While the blistering temperatures of 80°C in Philip K Dick’s dystopian novel exaggerate the effects of global warming, a future where heatwaves can melt shoes or animals are boiled alive, and where the failure of air conditioning can be a death sentence is our present reality. This summer, heat waves have scorched continents — monkeys and bats dropped dead in Mexico, New Delhi experienced forty consecutive days over 40°C, and more than 1,300 pilgrims died on the Hajj. The independent climate research group, Climate Central, reported that nearly five billion people — more than 60 per cent of the global population — experienced extreme heat in the June 16-24 period.

To cope with this excruciating heat, billions have cranked up their air conditioning unit. Use of this technology can drive electricity demand up as much as 50 per cent. In regions like North Africa, increasing usage of air conditioning can account for 30-70 per cent of peak electricity load.

All this cooling comes at a cost. In 2022, researchers estimated that air conditioning releases 1,950 million tons of carbon dioxide annually, or 3.94 per cent of global greenhouse emissions. Without any measures taken to improve efficiency or phase out fossil fuels, that amount of emissions could more than double by 2050. As of 2023, cooling accounts for 20 per cent of global energy consumption.

But as it gets hotter, more and more of the world is turning to air conditioning. A recent study in China found that for every additional day above 30°C, weekly AC unit sales rose 16.2 per cent. Since 2010, China has tripled its air conditioning stock to over 905 million units. Heatwaves in Europe have caused many to finally accept air conditioning. Africa’s demand for air conditioning is also accelerating rapidly, relying on imports of cheap but inefficient AC units to meet demands that strain its already overburdened power grids. By 2050, the number of air conditioning units in the world is expected to more than double to 5.6 billion.

AC units don’t just warm the planet through the extra emissions from power generation. The hydrofluorocarbon (HFC) refrigerants in AC units are a 1,000-3,000 times more potent greenhouse gas than carbon dioxide and slowly leak into the atmosphere over a unit’s lifetime. AC units also expel waste heat that can raise temperatures in heavily paved urban environments by 1-3°C. The hotter it gets, the more we use air conditioning, the hotter it gets — this is the vicious cycle of air conditioning in a warming world.

Despite these downsides, air conditioning is a lifesaver in a warming world. Global heat-related deaths between 2000 and 2019 were estimated at 489,000 per year. The 2022 summer heatwaves in Europe alone are estimated to have caused over 60,000 deaths. The 2023 Lancet report — an assessment of health outcomes due to climate change — estimated that with 2°C warming heat-related deaths could rise by 370 per cent.

But even today’s deadly heatwaves won’t compare to what the world would face at 3 or 4°C warming. In those scenarios, the risk of crossing critical heat thresholds increases significantly. At a wet-bulb temperature of 35°C  — a measure of the temperature at 100 per cent humidity — the human body is unable to cool through sweating. Under such conditions, without access to air conditioning a person has a survival threshold of about six hours.

Today, only some areas in the Middle East and South Asia experience wet bulb temperatures at 35°C for an hour or two, but a warmer world increases the risk. At 3°C warming, hundreds of millions would experience on average 3-plus weeks a year of temperatures above the critical wet bulb threshold. At 4°C warming, billions would. In that world, but increasingly also in ours, air conditioning becomes as critical as safe water access.

International efforts are underway to address the cooling problem. The Global Cooling Pledge, advanced at the COP28 in the UAE, seeks to reduce global cooling emissions by 68 per cent by 2050 through a combination of passive cooling technologies, adoption of higher energy efficient AC units, an accelerated phase-down of refrigerants with high Global Warming Potential (GWP), and decarbonisation of the electric grid. The pledge has since been signed by 71 countries, though notably lacks China and India as signatories. If the public can hold their governments accountable to their current announced climate pledges, the IEA estimates that air conditioning energy intensity,  the amount of energy required to produce a unit of GDP, will be reduced by a third by 2060.

To limit the use of high GWP HFCs, 81 per cent of countries have signed on to the Kigali Amendment to the Montreal Protocol, potentially preventing up to 105 billion tonnes of greenhouse gas emissions. AC units using the refrigerant R-32 are now hitting the market, reducing the GWP impact by 80 per cent and increasing energy efficiency by 12 per cent.

The burden needn’t be entirely placed on air conditioning, either. Passive cooling techniques such as insulated shading and ventilation can significantly reduce the cooling load on ACs. Architectural design to maximize the shading of buildings and air flows can improve these effects. Greening urban spaces by increasing tree canopy cover can also significantly lower temperatures.

Where green spaces are not viable, reflective pavement can help reduce surface air temperatures in open urban areas in cities like Phoenix, US. Water features like fountains and canals can also reduce air temperatures through evaporative cooling, just as sweating cools a person, though it may increase humidity and moist heat stress in tropical climates.

These climate-friendly urban infrastructures can work alongside AC to alleviate extreme heat, but they are not sufficient on their own. Public cooling centers are a low-cost, low-emission intervention that can provide refuge for people in areas with low air conditioning adoption, particularly for unhoused populations.

Most important of all is the imperative to demand climate action and accelerate a green energy transition. The good news is that global spending on renewable energy, power grids, and battery storage for the first time surpassed fossil fuels in 2023. Investment in solar photovoltaic (PV) technologies is now greater than all other power generation technologies. Recent efforts like the Global Cooling Prize contest have incentivised the development of new room air conditioners that produce five times less emissions over their lifetimes than existing units. The winners, Gree Electric Appliances and Daikin, are currently working to scale the technology for market by 2025. Adopted globally, these super-efficient AC units could mitigate 75 gigatons of greenhouse gas emissions by 2050 and prevent 0.5°C of warming by 2100.

But work still needs to be done. The IEA stresses that renewable energy capacity needs to triple and energy efficiency double by 2030 to meet the targets needed to keep the world below 1.5°C warming. China has already declined to sign on to the Global Renewables and Energy Efficiency Pledge, citing concerns that doubling energy efficiency by 2030 is unrealistic. Although the country is on track to triple renewable energy capacity, energy demand growth continues to accelerate, making it difficult to structurally transition from energy-intensive industrial sectors that rely on coal power. India also refused to sign onto the pledge out of concern that it would reduce the affordability of air conditioning.

If the world is to meet its climate targets, international organisations and wealthy countries need to provide accessible and fair funding to developing nations. Otherwise, the cheapest and least efficient paths towards cooling will be pursued out of necessity. Developing economies have been under immense financial pressure since the pandemic, paying exorbitant interest rates on financial loans that force them to implement disastrous austerity measures. In 2023 alone, the developing world has paid $68 billion more in interest and repayments than it has received in financial assistance.

The climate crisis demands global cooperation to solve global problems. Continuing to place profits and private corporations over people will only further global wealth inequality and prevent a sustainable green energy transition. Without international assistance, people in the Global South will protect themselves from a warming world by any means they can.

As the world continues to warm, people need air conditioning to cope with extreme heat. This doesn’t have to come at the cost of accelerating global warming. Through determined net-zero policies, innovative energy efficient technologies, and equitable global financial aid, we can ensure that summer days don’t have to be deadly, and our neighbour’s turtle won’t boil dry.

Image: Jens Schott Knudsen