At the moment, there is a very good audio programme on BBC Radio 4 from the series Costing the Earth. The episode is called Too Darn Hot and it focusses on air-conditioning. I definitely recommend it because it explores a massive problem in our modern world; the increasing alteration of our urban environment to fit in air-conditioning. As our planet warms up, it’s understandable that more people will want to use air-conditioning. The problem is that, in the last seventy-years, architects and construction companies have been creating buildings, worldwide, that depend on air-conditioning. They’ve actually replaced traditional structures, that were designed to naturally cool their occupants, with structures that have to have air-conditioning on to be habitable.

A very good, long article on the problem of air-conditioning-centric buildings is still available in the Guardian newspaper, entitled, The air conditioning trap: how cold air is heating the world. It contains some scary facts. For example, the projected energy use for air-con in our future is staggering:

There are just over 1bn single-room air conditioning units in the world right now – about one for every seven people on earth. Numerous reports have projected that by 2050 there are likely to be more than 4.5bn, making them as ubiquitous as the mobile phone is today. The US already uses as much electricity for air conditioning each year as the UK uses in total. The IEA projects that as the rest of the world reaches similar levels, air conditioning will use about 13% of all electricity worldwide, and produce 2bn tonnes of CO2 a year – about the same amount as India, the world’s third-largest emitter, produces today.

There is also a darker aspect to the story and I would recommend readers reading the whole article. It describes the history of air conditioning, and how power companies in the United States encouraged people to buy power-hungry air conditioners in order to increase the customers’ need for electrical power. They created a market for their product, in the same way the oil industry pushed for the creation of mass car-use. The power companies first pitched air-con as a glorious luxury to US homeowners, then as a necessity. This strategy has had serious effects. Builders began constructing houses and office buildings, throughout the States, with little interest in creating a home whose design reduced heat problems. Instead, they just fitted them with air-con. Companies then exported this American invention around the world, making office buildings in hot countries stay at twenty degrees centigrade, even though the native population were at home with thirty degree daily temperatures. The air-con industry has now reached the point, reports the Guardian article, that in a Beijing heatwave, half the power generation is used for air conditioning.

Air conditioning, not surprisingly, is therefore a disaster when it comes to climate change. Not only are fossil fuels being consumed to power these air-conditioners but air-conditioners are net heat generators. All the heat they remove from a room is simply pumped out the window, along with the waste heat created by running the motor and pump. Cities therefore become doubly-hot in heatwaves, as the ambient heat, magnified by concrete, tarmac and glass, is boosted by the air-con heat output. Many people will escape this heat by sitting in their air-conditioned cars, or entering air-conditioned offices but for the urban poor and homeless, their world becomes a baking hell.

Fortunately, we can do things very different. All we need to do is change how our buildings are designed and a lot of our heat problems will go away. For example, the ground under our feet is always around four degrees in temperate, summer or winter. This means that we therefore don’t need refrigerators if we live in a house with a ground floor. We can keep food cool by simply digging a hole in the ground, one that is protected and insulated and easy to clean. Many Japanese houses have this facility. The stable ground temperature also enables ground-source heat pumps to generate power, as they can use the temperature gradient, either negative or positive, between the ground and the air to generate power. It is also possible to keep the air in urban areas cool by building plant structures on the walls of buildings. The plants perspire and act as shade, both of which cool the air. Wimbledon Lawn Tennis built such a wall for its 2019 Championship, and it was a huge success. We don’t have to do it the air-con way. In truth, we can’t.