<p>Yes, there is. Hover over the left side of a comment and click in the up arrow to vote (try it in the sample comment I left under the question). Comments can't be downvoted. You will also see a flag beneath the up arrow; that is for flagging comments.</p>

<p><a href="https://stats.stackexchange.com/help/badges">Badges</a> related to commenting are 'Commentator' (bronze) and 'Pundit' (silver). The latter is the one related to voting. One needs to write 10 comments and each of them receive at least 5 upvotes (yes, numbers on the left represent the amount of votes a comment received). I think the intent of  the Pundit badge is reward users who write useful comments. Likewise voting on regular posts, a user can't vote for his/her own comments.</p>

<p>There are no badges for upvoting comments.</p>
