Um, yeah. Ziggy. Period. That's it. And I don't think it's even intended to be an Earth Day comic, really.
Now, admittedly, I haven't looked at EACH AND EVERY comic being published in any form today, but I've spent a good deal of time hunting. And I've got about bupkis to show for it. Wow. Way to be contemporary, folks. You can't even keep up with annual events?
I'll leave you with this cartoon that I drew for an email our company is sending out today to get people to switch to receiving electronic bills instead of paper ones.
END OF DAY UPDATE: In the Comments, Karen points out that she did find two more Earth Day strips from today that I had missed: Mutts and Grand Avenue. Thanks, Karen!