Niall Ferguson has a slight Malthusian thread running through his book, Civilization: The West and the Rest (My review is here and some other Malthusian thoughts by Ferguson here). At one point, Ferguson touches on the mass emigration from England to the Americas. Ferguson writes:
[A]s England’s population accelerated in the late seventeenth century, overseas expansion played a vital role in propelling the country out of the Malthusian trap. Transatlantic trade brought an influx of new nutrients like potatoes and sugar – an acre of sugar cane yielded the same amount of energy as 12 acres of wheat – as well as plentiful cod and herring. Colonization allowed the emigration of surplus population. Over time, the effect was to raise productivity, incomes, nutrition and even height.
The Chinese and Japanese route – turning away from foreign trade and intensifying rice cultivation – meant that with population growth, incomes fell, and so did nutrition, height and productivity. When crops failed or their cultivation was disrupted, the results were catastrophic.
If people are the ultimate resource, emigration of surplus population would have negative consequences. A lower population will generate fewer ideas. However, the surplus population that emigrated to the Americas was not completely lost to Europe. Those people continued to innovate, and ideas could flow between Europe and its colonies.
Ferguson suggests that emigration is positive as it loosens the Malthusian bindings on the population. It may have been the case for a time. Yet, the English population more than tripled between 1740 and 1860 as the flow of English emigrating declined and fertility boomed. It was during this population boom that per person income finally reached the levels seen in the low population period after the black death. England exited the Malthusian state at a time that the Malthusian model would suggest it was least likely to occur.