Are some latitudes or climates more conducive to human happiness than others?

Background

The 19th century Chinese political philosopher and dissident Kang Youwei wrote that among the more severe miseries of this life are: premature death, mutilation, slavery, and living outside of China. And Kang was hardly an innovator in this respect; indeed, he seems to have drawn on a long tradition in Chinese thought which holds that it’s only really possible to live a happy, civilised life on Chinese soil.

I’ve only ever set foot in China twice – both were very brief visits – and I can’t say I was much persuaded to Kang’s point of view. But such naked "geographical chauvinism", as I’ll call it, makes me question my own attitudes to distant lands. As an Englishman, writing at a latitude of 53 degrees north, it seems incredible to me that the fourth largest city in Europe is Saint Petersburg, at a latitude of 60 degrees north, where the sun doesn’t rise until after ten o’clock in the depths of winter. Likewise, as a younger man I served with the British navy in the Persian Gulf; it seemed incredible to me then that so many millions of people could withstand such an intense, coruscating bombardment of sunlight. Are these sentiments just an Englishman’s reproduction of Kang’s fallacy? Or is there some concrete evidence to support my intuitions?

Prior Research

Measuring a nation’s happiness is, of course, an impossibly thorny matter, both methodologically and philosophically, so much so that I won’t even bother to discuss the various national happiness scores, such as the Human Happiness Index. However, there do seem to be a couple of plausible ways to measure unhappiness: suicide rates and consumption of antidepressants.

According to an authoritative-looking list of countries by consumption of antidepressants, Iceland consumes more per capita than any other country, and by a comfortable margin. Iceland is also the most northerly country in the world as measured by the latitude of its capital city. (An interesting side-note: Greenland, currently under Danish sovereignty, is even further north, and has been called ‘The Suicide Capital of the World’.) The next most northerly country, Finland, is the eleventh highest consumer of antidepressants, and, with the exception of the post-Soviet states, the ten most northerly countries are all within the top fifteen consumers. These data, of course, need to be interpreted with a great deal of caution. For one thing, antidepressant consumption only measures how frequently a particular kind of treatment for depression is used; populations in other countries might be just as depressed, but, due to poverty, culture, etc, might not receive treatment, or might receive another kind of treatment.

The figures for rates of suicide seem to tell a slightly different story. There does seem to be a modest correlation between latitude and suicide rate; more northerly (or more southerly, in the southern hemisphere) countries do seem to have, on average, somewhat higher rates. But the epicentre for suicide is northeastern Europe, and not Scandinavia. And then there is the massive anomaly of India, which has quite a high suicide rate, is very much in the global south, and which accounts for a sixth of the world’s population. The Mediterranean factor, on the other hand, seems to support the hypothesis that some climates are more conducive to human happiness than others; almost every country with a Mediterranean coastline has a low suicide rate. (I was also struck by the seeming lack of a correlation between poverty and suicide, whereas I had expected there to be a strong link.)

Countries of the world by suicide rate in 2012. Higher rates correspond to darker colours.

What I’d Like to Know

• Is there are any interesting research on the relationship between latitude and extreme unhappiness (i.e. suicide, depression, etc)? If so, what does the consensus seem to be?
• Is there any interesting research on the relationship between climate and extreme unhappiness?
• Is there any interesting research on the relationship between latitude and climate on the one hand, and the more nebulous concept of human happiness on the other?