Russia is sparsely populated in Siberia because of it's government, the fact that Siberia is mostly muskeg like Alaska and the lack of transportation. Canada is underpopulated because of our government and the choice of most Canadians to not maintain replacement levels of children.
If the carrying capacity of Canada and Russia were higher, they would have greater populations.
Take a look at the per capita wealth of people on this planet. Where are the rich people? Show me the Tropical country in the top 30.
Here you have entirely missed the point. You're comparing the material comfort of a single individual surrounded by technological comforts (ie protected from the natural environment), to the actual carrying capacity of the environment. You need greater technology and industry to survive in colder climates. Otherwise you will freeze to death or starve to death when frost strikes. You have to have clothing, you must be able to build habitable dwellings.
Travelling in Samoa, I realized that the people did not need clothing or walls. It simply never got cold, there was abundant food, it's no wonder they were technologically primitive.
As a biological species, we thrive in warm climates. As masters of industrial technology and builders of large scale institutions, we are better off facing challenges.
While the Ganges river delta is incredibly fertile, Bangladesh cannot feed itself and is subject to the political influence and desires of the nations that send it food.
According to the CIA World Factbook, Bangladesh has 147M people, over four times the population of all of Canada. The country is 144K square km, giving Bangladesh a population density of 1K persons per square km.
It is one of the most overpopulated countries on Earth. It is also technologically backwards and impoverished. So, yes, it is obviously easier for humans to survive and breed in Bangladesh than, say, Alaska. Extreme overpopulation is not the result of a climate which is hostile to a species, rather it is entirely the opposite. The climate is so hospitable to human life, that the population has exploded beyond it's considerable carrying capacity.
Canada has 33M people, occupying a country of almost 10M sq km, giving it a population density of 3 persons per sq km. In other words, Bangladesh has 300 times the population density of Canada.
https://www.cia.gov/cia/publications/factbook/geos/bg.html#People
You say that it's easier to live in hot/warm climates. Bangladesh is the object example of the falsity of that statement. A farmer in Bangladesh cannot feed their self and their family. Contrast that to an American/Canadian farmer who not only grows enough for them selves, but also feeds hundreds of others.
This argument is completely specious. Canada and America are among the most technologically advanced nations in the world. Bangladesh is an extremely impoverished Third World nation with poor infrastructure. The higher yields of American farmers has nothing to do with climate and everything to do with technology, wealth, machinery, and infrastructure.
4.57% of Canada is arable land, compared to 55% for Bangladesh. If the climate and geography of Bangladesh were to suddenly morph into Nordic conditions, no amount of food aid would prevent the famine which would ensue. If Canada had 10 billion people, and the same level of economic and technological development as Bangladesh, you would not be a happy camper.
Compare apples to apples. What's the population density in the Himalayas? What parts of India are most overpopulated, the coldest parts or the warmer, wetter parts?
An increase in the mean Global Temperature of 2 degrees is going to make the average American/Canadian farmer even more productive. In Bangladesh, that increase will result in even less food being grown because the resulting rain will wash away even the crops in the highlands.
Again, this is a question of inadequate infrastructure, such as flood control and waterways.
Colder climates are more challenging for human beings by nature, as well as for most other animal species. The density of life drops off with the temperature and solar flux density, until it reaches almost complete desolation such as the Antarctic. During interglacial warm periods, habitability and carrying capacity of the Earth rises as it warms out of Ice Age.
Europe is now much warmer than it was during the Dark Ages, warmer than it was during the "Little Ice Age" which brought plagues and famine. Having survived more challenging conditions, our Northern civilizations have the happy coincidence of much more advanced technology, strong economic institutions, and low population densities. This provides us with an extraordinary quality of life, but to take this to mean that colder climates are more habitable for human beings is wrong.
