Every second, ten air conditioners are sold worldwide. By 2050, there will be nearly six billion. Invented in 1902 by American engineer Willis Carrier, the air conditioner has profoundly changed our contemporary societies. The cultural industry, first, accompanying the golden age of Hollywood cinema. The companies have then massequipped, air conditioning being deemed to increase the productivity of employees.

If it was not until the 1950s that air conditioners entered American households, they now represent, in the United States, an energy expenditure equivalent to that of the entire African continent.

Sources:

"Air conditioning to the onslaught of the planet" (Le Monde Diplomatique) https://www.mondediplomatique.fr/201...
A study on the link between heat and school
http://journals.plos.org/plosmedicine...
A study on the link between temperatures and productivity
https://www.ncbi.nlm.nih.gov/pmc/arti...
A study on the link between natality and temperatures
http://ftp.iza.org/dp9480.pdf
The impact of the air conditioner on the number of hospitalizations
https://academic.oup.com/aje/article/...
A study on the decline of heatrelated mortality
https://poseidon01.ssrn.com/delivery....
On the dynamism of the Sun Belt
https://www.hks.harvard.edu/sites/def...
A book by Nelson Polsby
https://books.google.fr/books?id=7CfR... 20conditioning% & f = false
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https://www.curbed.com/2017/7/20/1600...
The air conditioner, revealing inequalities
https://www.ncbi.nlm.nih.gov/pmc/arti...
A study on the increase of the temperatures because of the air conditioners
https://agupubs.onlinelibrary.wiley.c...
Figures on the evolution of the air conditioning market
http://www.iea.org/cooling/