A reminder that air conditioning is not a real solution to face extreme heat
As temperatures get higher and higher each summer in Western countries, more and more people are inclined to buy an air conditioner. Indeed, air conditioning is a good way of relieving the increase of heat in houses. But it is not sustainable and might in the contrary increase the general temperature in cities and Greenhouse gas emissions.
AC as a way of facing extreme heat
As Statistics Canada report shows, air conditioning can be a very effective way of reducing heat-related morbidity, especially among old and vulnerable people. For others, it is mostly a question of comfort and also a way of reducing the high humidity levels in some region.
But the use of AC depends on countries and habits of their people. For example, most people in the US are equipped with AC whereas there are only 5% of homes which have AC in France, the United Kingdom and Germany. This can be explained by the fact that AC is necessary in some US regions as in the South and Southwest due to very humid or desertic climates. However, the intensive use of AC is also explained by the habit of having a very cool house in the US.
Problems with air conditioning
Air conditioning has many problems that explain why it is not a sustainable way of cooling houses.
AC affects the power grid
In summer, the use of AC by thousands of households can create demand peaks of electricity and therefore increase the possibility of a blackout. Many people using AC at the same time can also increase the price of electricity since the most expensive power plant is online so as to face the electricity peak.
AC contributes to global warming
AC is in fact very bad for the environment.
Firstly, AC works as heat pumps : it remove heat from the inside to the outside. It means that using AC in a city would increase the general temperature of the city. It creates a vicious circle that would encourage people to get air conditioning to reduce the heat created by air conditioning.
Secondly, air conditioners need a lot of electricity. More and more AC would mean an increase of energy demand and increase the Greenhouse gas with fossil fuel-powered plants being used. According to a study by the IEA (International Energy Agency), CO2 emissions associated with AC tripled between 1990 and 2022.
Finally, AC use hydrofluorocarbons (HFCs) as coolants which can contribute even more than carbon dioxide to global warming. When AC reach their end of lives, some HFCs can be released.
AC is a very unfair solution to face extreme heat
Buying and running an air conditioner can be very expensive. Some studies show that lower-income households struggle the most to get AC in the US. Moreover, in developing countries, “between 1.8 and 4.1 billion, depending on the required indoor temperatures and days of exposure, may need AC to avoid heat related stresses under current climate and socio-economic conditions” 
What should be done ?
So as to face extreme heat, there are other solutions than AC (although it remains necessary for vulnerable people) that can be developed. For example, efforts should be done in increasing the energy efficiency of building. So as to reduce heat in cities, more trees should be planted so as to avoid heat island effect.
Unfortunately, there is no perfect solution to face extreme temperature without AC. For future heat waves, we should learn to live with it and grin and bear it.
 Alessio Mastrucci, Edward Byers, Shonali Pachauri, Narasimha D. Rao, Improving the SDG energy poverty targets: Residential cooling needs in the Global South, Energy and Buildings, Volume 186, 2019, Pages 405-415,