How did civil war abolish slavery?

In reality, the Civil War itself did not abolish slavery. Abraham Lincoln issued the Emancipation Proclamation in 1862, declaring all slaves within any state of the Confederacy that did not return to the Union by the following year. There were still slaves in such states as Missouri, Maryland, West Virginia and Delaware that had not seceded. But those slaves were freed through individual state and federal actions beyond those of the Civil War or the Emancipation Proclamation