I'm not really sure how to break down "evidence-based" any more for you. It's pretty self-explanatory. Virtue signalling refers to actions that indicate you care about a topic (the environment in this case) but without any real commitment to the cause. For example, politicians who want to appear to care for the environment might promote a ban on plastic straws because it generates lots of good publicity, is only most mildly inconvenient, and is transparently negligible with respect to saving the planet ("better than nothing" unless one accounts for the squandered political will).