Dunno about over there, but climate change in my lifetime (I'm 27) has decimated the bee population in this country, we have very few butterflies any more, wasps and other flies are scarce now compared to 10 or 15 years ago. Visible changes to our climate in such a short space of time are pretty damned scary, and not something to be dismissed as not a real problem. If removing a few plastic bags can help reduce these effects, then why not?