I’m sure the experts and flared users here could give you much more of a comprehensive answer. Still, I can speak a bit on the economic viability of slavery in North America compared to the West Indies. Simply put, the sugar plantations of the Caribbean exploited slave labor in a much more demanding and exhaustive way than the United States. When the United States and Britain abolished the slave trade in 1807 1808, respectively, the slave populations diverged sharply due to the “inability of the slave population to reproduce itself.” [1] We must be careful here, as I do not want to undermine the brutal and exploitative nature of slavery in the United States. There is a consensus that enslaved people on sugar plantations faced harsher conditions and lower life expectancy, and the business of slavery was fundamentally different than the United States.

As a note: discussing the economics of slavery is a precarious endeavor for any historian seeking to engage with the subject. While econometrics is an instrumental field to help us better reconstruct the past, it is necessary to remember the immense suffering and violence that enslaved people faced every day. Moreover, the system of slavery itself was perpetually violent, dehumanizing, and egregiously exploitative.

​

Your question concerns the end of slavery, and as such, we should survey both regions on the eve of abolition. In the West Indies, absentee landowners used sugar plantations as foreign investments into a cash crop in high demand. Professional overseers managed these plantations, and the Black population significantly outnumbered the White population by as many as 90 to 1. As a result, slaves were worked essentially to death, and although that is a bit hyperbolic, it is relatively accurate. This fact is evident by sugar colonies’ heavy reliance on imported slave labor-- enslaved people in the West Indies rarely survived long enough to reproduce. It was often cheaper to import new slaves than invest in raising children. When the British and Americans banned the slave trade, it was nearly impossible to maintain a self-sustaining slave population, thus leading to less profitability and eventual abolition.

Compare this to the American South. Despite the importation of enslaved people becoming illegal in 1808, the enslaved Blacks’ population increased steadily every year. The phrase “King Cotton” is often repeated, and by the 1830s, the profitability of cotton was in full swing. Thus, slavery was highly profitable for all parties involved. There are two primary ways to look at slavery from an economic perspective. First, one may examine the labor system of slavery, which is the profits earned from the harvesting, processing, and sale of agricultural products. Second, and more important to our conversation, is the capital investment into human beings as a commodity. Historians like Alfred H. Conrad and Robert Fogel have argued for a 6% return on investment to slaveowners, and I think this is still a relatively accepted number. The perpetuating chattel system developed in the United States gave way for the controversial business of “slave breeding.” (I find this term to be highly problematic for various reasons. If anyone has a more modern phrase, please let me know). In general, states in the Chesapeake region found less and less use for enslaved people as laborers. Instead, many turned to expand the internal slave trade, in which enslaved labor would be redirected to the Cotton Belt and the expanding western territories. Thus, both the supply and demand sides of the internal slave trade remained profitable-- plantation owners invested heavily into human capital for free labor, and slave “breeders” (again, I hate this term) turned profits through the distribution of enslaved people.

To summarize: the slave populations in the British Caribbean could not sustain themselves compared to the slave population in the United States. The labor systems were fundamentally different, and enslaved people in the United States were highly valuable commodities while viewed as exhaustive laborers in the Caribbean.

[1] Alfred H. Conrad and John R. Meyer, “The Economics of Slavery in the Antebellum South” The Journal of Political Economy, Vol 66, 2. (1958): 112. https://www.jstor.org/stable/1827270

Other Sources:

Robert Fogle, Time on the Cross: The Economics of American Negro Slavery (1974)

Seth M. Rockman, Scraping By: Wage Labor, Slavery, and Survival in Early Baltimore (2009).