[vasco]

I don't know anything about the Romans so was giving you the benefit of the doubt but when you said European seafaring were due to climate I knew you were wrong. They had nothing to do with climate and instead with discovering new lands for the pope (regardless if there were people there already and the debate about calling it discoveries).

[inawarminister]

That's the explorers, yes, but the settlers?

Remember that the 1700s was so cold relatively, the soldiers march even in summer with thick jackets and smokepipes.

Though, there was also the introduction of potato, which led to massive demographic explosion in the Protestant Northern Europe.

But I do see your point. Still, the Germanic tribes were the first climate refugees that we know, maybe after the 8.2 kya event [0] that led to the first cities in Fertile Crescent

[0] https://en.wikipedia.org/wiki/8.2-kiloyear_event

[vasco]

The settlers were mostly slaves brought from Africa, the few Europeans were there because of the natural resources or because they were deemed to incompetent for administration of the "metropolis". Also discoveries began in the 1400s, calling events of climate of 300 years later a climate induced endeavor is a big stretch.