Summary of Rousseau in his work "Essay on the Origins of Language" according to Wikipedia:
"Rousseau writes that language (as well as the human race) developed in southern warm climates and then migrated northwards to colder climates. In its inception, language was musical and had emotional power as opposed to rational persuasion. The colder climates of the north, however, stripped language of its passionate characteristic, distorting it to the present rational form."
This makes a lot of sense, and colder temperatures do seem to make people more neurotic. From https://www.the-independent.com/news/neurotic-french-are-opposite-of-extrovert-british-1133708.html
"When all the ingredients from the countries were put together and analysed, Hungary came out the most neurotic country, and the US the most extrovert. The least neurotic country was Egypt, followed by Turkey and the Dominican Republic. The least extrovert country was Spain, closely trailed by Portugal and Chile.
The Germans, Swiss and Austria were also classed as neurotic extroverts. "At the extreme level in the individual, neurotic extroverts can be hysterics or psychopaths, individuals who are anti-social with no shame, guilt or remorse," Professor Lester said."
Ofc there could be many other factors IE Greece's can be caused by financial strain but the climate is probably a very big factor.
Lets us look at at this for a piece of the puzzle as well
Average Number of Sexual Partners by Country 2026
https://worldpopulationreview.com/country-rankings/average-number-of-sexual-partners-by-country
Top 10 countries by climate
Turkey: Southern
Australia: Southern
New Zealand: Southern
Iceland:Northern
South Africa: Southern
Finland: Northern
Norway:Northern
Italy:Southern
Sweden:Northern
Switzerland:Southern
6/10 are southern so climate probably plays a factor
And as for fertility take a look at CANZUK
https://worldpopulationreview.com/country-rankings/total-fertility-rate
UK: 1.63
CANADA: 1.58
AUSTRALIA: 1.73
NEW ZEALAND: 1.85
Austealia and NZ are also probably more homogeneous than UK/Canada too so the difference could be stronger. (Not to mention the highest tfr apart from non white countries being in warm climates as well ie Israel or africa)
Tldr: I believe southern climates make people happier, more virile, and more prone to having kids. Southern hospital climate with a northeners genius could produce incredible results.
Thoughts? Agree? Disagree?