As Clifton Middleton suggests, the marijuana laws need to be changed (if not disposed of outright).
In addition, it needs to be recognized that the legal system in America treats African-Americans differently across the board. They are more likely to be incarcerated than a white person, even when the crime is the same, and when they are jailed the sentences are more punitive.
The biggest untalked-about issue, though, is that African-American youths look older than their same-age white counter-parts (to predominantly white judges and jurors), so they are often treated as more culpable in a court setting and thus are much more likely to do time than their white peers. They are therefore more likely to be tried as an adult and/or jailed in an adult detention center. This means that these youths then fall victim to all of the issues of mental health, disease and employment prospects noted in Meredith Kirby’s piece.
Sentencing should be a separate process to the ascertaining of guilt, the agreed-upon facts of the case should be presented to a judge (and jury, if appropriate) in summary form, with all names and signifiers of race removed. The sentencing, then, can be applied based on the facts of the matter only. In other words, the legal system needs to remove the possibility of even unconscious bias (which is well documented in the legal system).