Geography is destiny and while terrain, or topography, certainly was a tactical aid, or detriment, on the battlefield, there is another way of answering that question. Consider the geography of the American South and the American North which, of course includes climate. Slavery, though lawful in all of the thirteen Colonies, thrived, and survived, in only those parts of America where labor intensive, semi tropical crops were cultivated. If rice grew in Massachusetts, indigo in Ohio and sugar in Iowa, slavery would have flourished there and with the economy of the whole country dependent on servile labor the Abolitionists would have been about as influential in New England as vegans in Omaha.