Here's an idea that could do more good than fish on Fridays (though as a fish lover, I suggest fish not only on Fridays but on Wednesdays and Mondays as well)--Reduce your carbon intake for the next forty days.
This suggestion from two Church of England bishops is reported by Tearfund, a UK charity that fights global poverty on many fronts. The article includes several practical suggestions, including "snubbing plastic bags."
Merriam-Webster Online defines snub thus: "to check or stop with a cutting retort" or "to treat with contempt or neglect." Have the good bishops gone too far? Do we have to snub the bags? Will it be OK if we just politely refuse them?