Pandoc currently has the --quiet option that suppresses all warnings:

--quiet
    Suppress warning messages.

However, it would be nice to be able to suppress specific warning messages. For example, when we batch-convert Markdown documents to HTML, we are happy with the default behavior of using the filename as the document title, and we would like to suppress this message:

[WARNING] This document format requires a nonempty <title> element.
  Defaulting to 'some_document.md' as the title.
  To specify a title, use 'title' in metadata or --metadata title="...".

but we don't want to use --quiet because it might hide other content issues that we do need to know about.

I suppose every message would need an identifier to reference it, and across multiple plugins, so perhaps this is an unrealistic request. If so, we should close this request.