As an institution, slavery existed in North America from about 1619, through and including the ACW, right up until the 13th Amendment was ratified in 1865, i.e., a total of nearly 250 years BEFORE the ACW. The ACW represented only about 4 and 1/2 years of this time, or less than 2 percent of the time during which slavery existed in North America. More to the point, the ACW did little if anything to alter the practice of slavery in those ever-fewer number of states that continued the practice slavery during the ACW.
Clearly, the ACW was not responsible for either starting or continuing slavery on the North American continent. In this broader context, whether the ACW was or was not triggered by slavery is of no real consequence in my opinion, and trying to link one with the other is nothing more than an attempt to obfuscate slavery's real issues and the real complexity in even addressing slavery intelligently.
Moreover, "reparations" as it is being discussed now, is in my view, purely a product of the late 20th and 21st centuries. Today's discussion seems to have, at best, only VERY tenuous connections, if any at all, to the ACW and is just the latest in a long sequence of unrelated "reparations" discussions that are a part of our history since the United States became the United States.
Trying to link "reparations," as it is being discussed today, with the ACW seems to amount to not much more than trying to give an old discussion new legs (this time, of historic proportions) in the hope that political leverage will result, but such is not the case.
For an interesting discussion of this, see http://en.wikipedia.org/wiki/Reparations_for_slavery